by Felipe Balbi

[permalink] [raw]

Subject: Re: [RFC][PATCH 3/5] OMAP SSI driver code

continuing with this patch

On Tue, Oct 07, 2008 at 03:03:09AM +0300, Felipe Balbi wrote:
> On Fri, Oct 03, 2008 at 02:52:28PM +0300, Carlos Chinea wrote:
>
> Description. This seems to repeat in all your patches, take a look at
> linux kernel patch format: http://linux.yyz.us/patch-format.html
>
> > Signed-off-by: Carlos Chinea <[email protected]>
> > ---
> > drivers/misc/ssi/Kconfig | 11 +
> > drivers/misc/ssi/Makefile | 7 +
> > drivers/misc/ssi/ssi_driver.c | 513 +++++++++++++++++++++++++++++++++++++
> > drivers/misc/ssi/ssi_driver.h | 211 +++++++++++++++
> > drivers/misc/ssi/ssi_driver_bus.c | 192 ++++++++++++++
> > drivers/misc/ssi/ssi_driver_dma.c | 406 +++++++++++++++++++++++++++++
> > drivers/misc/ssi/ssi_driver_if.c | 335 ++++++++++++++++++++++++
> > drivers/misc/ssi/ssi_driver_int.c | 232 +++++++++++++++++
> > 8 files changed, 1907 insertions(+), 0 deletions(-)
> > create mode 100644 drivers/misc/ssi/Kconfig
> > create mode 100644 drivers/misc/ssi/Makefile
> > create mode 100644 drivers/misc/ssi/ssi_driver.c
> > create mode 100644 drivers/misc/ssi/ssi_driver.h
> > create mode 100644 drivers/misc/ssi/ssi_driver_bus.c
> > create mode 100644 drivers/misc/ssi/ssi_driver_dma.c
> > create mode 100644 drivers/misc/ssi/ssi_driver_if.c
> > create mode 100644 drivers/misc/ssi/ssi_driver_int.c
> >
> > diff --git a/drivers/misc/ssi/Kconfig b/drivers/misc/ssi/Kconfig
> > new file mode 100644
> > index 0000000..5e0842c
> > --- /dev/null
> > +++ b/drivers/misc/ssi/Kconfig
> > @@ -0,0 +1,11 @@
> > +#
> > +# OMAP SSI HW kernel configuration
> > +#
> > +config OMAP_SSI
> > + tristate "OMAP SSI hardware driver"
> > + depends on ARCH_OMAP
> > + default n
> > + ---help---
> > + If you say Y here, you will enable the OMAP SSI hardware driver.
> > +
> > + If unsure, say N.
> > diff --git a/drivers/misc/ssi/Makefile b/drivers/misc/ssi/Makefile
> > new file mode 100644
> > index 0000000..2b74e02
> > --- /dev/null
> > +++ b/drivers/misc/ssi/Makefile
> > @@ -0,0 +1,7 @@
> > +#
> > +# Makefile for SSI drivers
> > +#
> > +omap_ssi-objs := ssi_driver.o ssi_driver_dma.o ssi_driver_int.o \
> ^ trailing whitespace
>
> > + ssi_driver_if.o ssi_driver_bus.o
> > +
> > +obj-$(CONFIG_OMAP_SSI) += omap_ssi.o
> > diff --git a/drivers/misc/ssi/ssi_driver.c b/drivers/misc/ssi/ssi_driver.c
> > new file mode 100644
> > index 0000000..292e868
> > --- /dev/null
> > +++ b/drivers/misc/ssi/ssi_driver.c
> > @@ -0,0 +1,513 @@
> > +/*
> > + * ssi_driver.c
> > + *
> > + * Implements SSI module interface, initialization, and PM related functions.
> > + *
> > + * Copyright (C) 2007-2008 Nokia Corporation. All rights reserved.
> > + *
> > + * Contact: Carlos Chinea <[email protected]>
> > + *
> > + * This program is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU General Public License
> > + * version 2 as published by the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope that it will be useful, but
> > + * WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> > + * General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU General Public License
> > + * along with this program; if not, write to the Free Software
> > + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
> > + * 02110-1301 USA
> > + */
> > +
> > +#include <linux/err.h>
> > +#include "ssi_driver.h"
> > +
> > +static void ssi_dev_release(struct device *dev)
> > +{
> > +}
> > +
> > +static void __init ssi_undo_reg_dev(struct platform_device *pd,
> > + int p, int ch)
>
> Take a few tabs out of the second line, it'll look better.
>
> > +{
> > + struct ssi_platform_data *p_data =
>
> normally we call it pdata, but it's your call in this case
>
> > + (struct ssi_platform_data *) pd->dev.platform_data;
>
> unnecessary cast. Remove
>
> > + struct ssi_port *ssi_p;
> > + int port;
> > + int channel;
> > +
> > + for (port = p; port >= 0; port--) {
> > + ssi_p = &p_data->ssi_ctrl->ssi_port[port];
> > + for (channel = ch; channel >= 0 ; channel--)
> > + device_unregister(&ssi_p->ssi_channel[channel].dev
> > + ->device);
>
> This function should be unnecessary. pdata usage is wrong.
>
> > + }
> > +}
> > +
> > +static int __init reg_ssi_dev_ch(struct platform_device *pd,
> > + unsigned int p, unsigned int ch)
>
> the following should be probe().
>
> > +{
> > + struct ssi_device *dev;
> > + struct ssi_platform_data *p_data =
> > + (struct ssi_platform_data *) pd->dev.platform_data;
>
> unnecessary cast, remove.
>
> > +
> > + dev = kzalloc(sizeof(*dev), GFP_KERNEL);
> > + if (!dev)
> > + return -ENOMEM;
> > + dev->n_ctrl = pd->id;
> > + dev->n_p = p;
> > + dev->n_ch = ch;
> > + dev->ch = &p_data->ssi_ctrl->ssi_port[p].ssi_channel[ch];
> > + p_data->ssi_ctrl->ssi_port[p].ssi_channel[ch].dev = dev;
>
> pdata usage is wrong. It should be used to initialize a few fields in
> the device structure and then vanish.
>
> > + dev->device.bus = &ssi_bus_type;
> > + dev->device.parent = &pd->dev;
> > + dev->device.release = ssi_dev_release;
> > + if (dev->n_ctrl < 0)
> > + snprintf(dev->device.bus_id, sizeof(dev->device.bus_id),
> > + "omap_ssi-p%u.c%u", p, ch);
> > + else
> > + snprintf(dev->device.bus_id, sizeof(dev->device.bus_id),
> > + "omap_ssi%d-p%u.c%u", dev->n_ctrl, p, ch);
> > +
> > + return device_register(&dev->device);
> > +}
> > +
> > +static int __init register_ssi_devices(struct platform_device *pd)
> > +{
> > + struct ssi_platform_data *p_data =
> > + (struct ssi_platform_data *) pd->dev.platform_data;
>
> unnecessary cast. Remove
>
> > + unsigned int n_ch = 0;
> > + int port;
> > + int ch = 0;
> > + int err = 0;
> > +
> > + for (port = 0; ((port < p_data->num_ports) && (err >= 0)); port++) {
> > + n_ch = max(p_data->ports[port].tx_ch,
> > + p_data->ports[port].rx_ch);
> > + for (ch = 0; ((ch < n_ch) && (err >= 0)); ch++)
> > + err = reg_ssi_dev_ch(pd, port, ch);
> > + }
> > +
> > + if (err < 0) {
> > + port--;
> > + ch--;
> > + dev_err(&pd->dev, "Error registering ssi device channel "
> > + "p%d-c%d : %d\n", port, ch, err);
> > + if ((port == 0) && (ch == 0))
> > + return err;
> > + else if ((port > 0) && (ch == 0))
> > + ch = n_ch;
> > + ssi_undo_reg_dev(pd, port, ch);
> > + }
> > + return err;
> > +}
> > +
> > +static int __init ssi_softreset(struct ssi_dev *ssi_ctrl)
> > +{
> > + int ind = 0;
> > + void __iomem *base = ssi_ctrl->base;
> > + u32 status;
> > +
> > + ssi_outl_or(SSI_SOFTRESET, base, SSI_SYS_SYSCONFIG_REG);
> > +
> > + status = ssi_inl(base, SSI_SYS_SYSSTATUS_REG);
> > + while ((!(status & SSI_RESETDONE)) && (ind < SSI_RESETDONE_RETRIES)) {
> > + set_current_state(TASK_UNINTERRUPTIBLE);
> > + schedule_timeout(msecs_to_jiffies(SSI_RESETDONE_TIMEOUT));
> > + status = ssi_inl(base, SSI_SYS_SYSSTATUS_REG);
> > + ind++;
> > + }
> > +
> > + if (ind >= SSI_RESETDONE_RETRIES)
> > + return -EIO;
> > +
> > + /* Reseting GDD */
> > + ssi_outl_or(SSI_SWRESET, base, SSI_GDD_GRST_REG);
> > +
> > + return 0;
> > +}
> > +
> > +static void __init set_ssi_ports_default(
> > + struct platform_device *pd)
> > +{
> > + struct ssi_port_pd *cfg = NULL;
> > + struct ssi_platform_data *p_data =
> > + (struct ssi_platform_data *) pd->dev.platform_data;
> > + unsigned int port = 0;
> > + void __iomem *base = p_data->ssi_ctrl->base;
>
> is this really a virtual address?? then can you use
> __raw_{read,write}[blw]() and drop ssi-specific read/write functions?
>
> btw, the base address shouldn't come via pdata, it should come via
> struct resource and get ioremap:ed in the driver. Recently we fixed all
> the physical/virtual address mess and if we accept this it'll lead to
> similar issues. Please fix.
>
> > +
> > + for (port = 1; port <= p_data->num_ports; port++) {
> > + cfg = &p_data->ports[port - 1];
> > + ssi_outl(cfg->tx_mode, base, SSI_SST_MODE_REG(port));
> > + ssi_outl(cfg->tx_frame_size, base, SSI_SST_FRAMESIZE_REG(port));
> > + ssi_outl(cfg->divisor, base, SSI_SST_DIVISOR_REG(port));
> > + ssi_outl(cfg->tx_ch, base, SSI_SST_CHANNELS_REG(port));
> > + ssi_outl(cfg->arb_mode, base, SSI_SST_ARBMODE_REG(port));
> > +
> > + ssi_outl(cfg->rx_mode, base, SSI_SSR_MODE_REG(port));
> > + ssi_outl(cfg->rx_frame_size, base, SSI_SSR_FRAMESIZE_REG(port));
> > + ssi_outl(cfg->rx_ch, base, SSI_SSR_CHANNELS_REG(port));
> > + ssi_outl(cfg->timeout, base, SSI_SSR_TIMEOUT_REG(port));
> > + }
> > +}
> > +
> > +static int __init ssi_port_channels_init(
> > + struct platform_device *pd, unsigned int lport)
> > +{
> > + struct ssi_platform_data *p_data =
> > + (struct ssi_platform_data *) pd->dev.platform_data;
> > + struct ssi_channel *ch;
> > + struct ssi_port *port;
> > + unsigned int n_ch;
> > + unsigned int ch_i;
> > +
> > + n_ch = max(p_data->ports[lport].tx_ch, p_data->ports[lport].rx_ch);
> > + port = &p_data->ssi_ctrl->ssi_port[lport];
> > + for (ch_i = 0; ch_i < n_ch; ch_i++) {
> > + ch = &port->ssi_channel[ch_i];
> > + ch->channel_number = ch_i;
> > + ch->flags = 0;
> > + ch->ssi_port = port;
> > + ch->read_data.addr = NULL;
> > + ch->read_data.size = 0;
> > + ch->read_data.lch = -1;
> > + ch->write_data.addr = NULL;
> > + ch->write_data.size = 0;
> > + ch->write_data.lch = -1;
> > + spin_lock_init(&ch->ssi_ch_lock);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int __init ssi_ports_init(struct platform_device *pd)
> > +{
> > + struct ssi_platform_data *p_data =
> > + (struct ssi_platform_data *) pd->dev.platform_data;
>
> unnecessary cast. Remove
>
> > + struct ssi_port *ssi_p = NULL;
> > + unsigned int port = 0;
> > + unsigned int err = 0;
> > + unsigned int n_ports;
> > +
> > + n_ports = min(p_data->num_ports, (u8)SSI_MAX_PORTS);
> > +
> > + for (port = 0; ((port < n_ports) && (err >= 0)); port++) {
> > + ssi_p = &p_data->ssi_ctrl->ssi_port[port];
> > + ssi_p->port_number = port + 1;
> > + ssi_p->ssi_controller = p_data->ssi_ctrl;
> > + ssi_p->max_ch = max(p_data->ports[port].tx_ch,
> > + p_data->ports[port].rx_ch);
> > + ssi_p->max_ch = min(ssi_p->max_ch, (u8)SSI_PORT_MAX_CH);
> > + ssi_p->n_irq = p_data->ports[port].n_irq;
> > + ssi_p->irq = 0;
> > + spin_lock_init(&ssi_p->lock);
> > + err = ssi_port_channels_init(pd, port);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int __init ssi_controller_init(struct platform_device *pd)
> > +{
> > + struct ssi_platform_data *p_data =
> > + (struct ssi_platform_data *) pd->dev.platform_data;
> > + struct ssi_dev *ssi_ctrl = p_data->ssi_ctrl;
> > + int err;
> > +
> > + ssi_ctrl->id = pd->id;
> > + ssi_ctrl->max_p = p_data->num_ports;
>
> in the header file you have a define for the max_ports and here you use
> platform_data to initialize it. Quite weird. Where are you using that
> define ?
>
> > + ssi_ctrl->pdev = pd;
>
> do not save the entire pdev pointer, save only the dev pointer use
> platform_set_drvdata(pdev, ssi_ctrl);
>
> > + spin_lock_init(&ssi_ctrl->lock);
> > + ssi_ctrl->ssi_clk = clk_get(&pd->dev, p_data->clk_name);
>
> please don't.
>
> > + if (IS_ERR(ssi_ctrl->ssi_clk)) {
> > + dev_err(&pd->dev, "Unable to get SSI clocks");
> > + return PTR_ERR(ssi_ctrl->ssi_clk);
> > + }
> > +
> > + err = ssi_ports_init(pd);
> > + if (err < 0) {
> > + dev_err(&pd->dev, "Error on ssi_controller initialization");
> > + clk_put(ssi_ctrl->ssi_clk);
> > + return -EBUSY;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static void ssi_controller_exit(struct platform_device *pd)
> > +{
> > + struct ssi_platform_data *p_data =
> > + (struct ssi_platform_data *) pd->dev.platform_data;
>
> unnecessary cast, remove.
>
> > + struct ssi_dev *ssi_ctrl = p_data->ssi_ctrl;
> > +
> > + p_data->ssi_ctrl = NULL;
> > + ssi_ctrl->pdev = NULL;
> > + clk_put(ssi_ctrl->ssi_clk);
> > +
>
> unnecessary extra white line, remove.
>
> > +}
> > +
> > +static int __init request_ssi_irqs(struct platform_device *pd)
> > +{
> > + struct ssi_platform_data *p_data = pd->dev.platform_data;
> > + struct ssi_dev *ssi_ctrl = p_data->ssi_ctrl;
> > + struct ssi_port *ssi_p;
> > + struct resource *mpu_irq;
>
> unnecessary if it's only to get the irq.
>
> > + int i;
> > + int j;
> > + int err = 0;
> > +
> > + for (i = 0; ((i < p_data->num_ports) && (!err)); i++) {
> > + mpu_irq = platform_get_resource(pd, IORESOURCE_IRQ, i*2);
>
> no
>
> > + if (!mpu_irq) {
> > + dev_err(&pd->dev, "SSI misses info for MPU IRQ"
> > + " on port %d", i + 1);
> > + err = -ENODEV;
>
> use a goto to create a nice error path, then you remove this else below.
>
> > + } else {
> > + ssi_p = &ssi_ctrl->ssi_port[i];
> > + ssi_p->n_irq = 0; /* We only use one irq line */
> > + ssi_p->irq = mpu_irq->start;
>
> ssi_p->irq = platform_get_irq(pdev, 0);
> also gets rid of the unnecessary mpu_irq.
>
> > + tasklet_init(&ssi_p->ssi_tasklet,
> > + do_ssi_tasklet, (unsigned long)ssi_p);
> > + err = request_irq(mpu_irq->start, ssi_mpu_handler,
> > + IRQF_DISABLED, mpu_irq->name, ssi_p);
> > + if (err < 0) {
> > + dev_err(&pd->dev, "FAILED request IRQ (%d)",
> > + mpu_irq->start);
> > + err = -EBUSY;
> > + }
> > + }
> > + }
> > +
> > + if (err < 0) {
> > + /* Let's free the reserved resources if there are any errors */
> > + for (j = 0; (j > (i-1)); j++) {
> > + printk(KERN_DEBUG LOG_NAME "Free resources on port %d",
> > + j+1);
> > + ssi_p = &ssi_ctrl->ssi_port[i];
> > + tasklet_disable(&ssi_p->ssi_tasklet);
> > + free_irq(ssi_p->irq, ssi_p);
> > + }
> > + }
> > +
> > + return err;
> > +}
> > +
> > +static int __init request_ssi_gdd_irq(struct platform_device *pd)
> > +{
> > + struct ssi_platform_data *p_data = pd->dev.platform_data;
> > + struct ssi_dev *ssi_ctrl = p_data->ssi_ctrl;
> > + struct resource *gdd_irq;
>
> no
>
> > + int err = 0;
> > +
> > + gdd_irq = platform_get_resource(pd, IORESOURCE_IRQ, 4);
>
> no
>
> > + if (!gdd_irq) {
> > + dev_err(&pd->dev, "SSI device has no info about GDD IRQ");
> > + return -ENODEV;
> > + }
> > +
> > + ssi_ctrl->gdd_irq = gdd_irq->start;
>
> hell no. Use platform_get_irq() like I said before.
>
> > + err = request_irq(gdd_irq->start, ssi_gdd_mpu_handler,
> > + IRQF_DISABLED, gdd_irq->name, ssi_ctrl);
> > + if (err < 0) {
> > + dev_err(&pd->dev, "FAILED to request IRQ NUMBER (%d)",
> > + gdd_irq->start);
> > + return -EBUSY;
> > + }
> > + tasklet_init(&ssi_ctrl->ssi_gdd_tasklet, do_ssi_gdd_tasklet,
> > + (unsigned long)ssi_ctrl);
> > +
> > + return err;
> > +}
> > +
> > +static void free_ssi_irqs(struct ssi_dev *ssi_ctrl)
> > +{
> > + struct ssi_port *ssi_p;
> > + int i;
> > +
> > + for (i = 0; (i < ssi_ctrl->max_p); i++) {
> > + ssi_p = &ssi_ctrl->ssi_port[i];
> > + tasklet_disable(&ssi_p->ssi_tasklet);
> > + free_irq(ssi_p->irq, ssi_p);
> > + }
> > +}
> > +
> > +static void free_ssi_gdd_irq(struct ssi_dev *ssi_ctrl)
> > +{
> > + tasklet_disable(&ssi_ctrl->ssi_gdd_tasklet);
> > + free_irq(ssi_ctrl->gdd_irq, ssi_ctrl);
> > +}
> > +
> > +static int __init ssi_probe(struct platform_device *pd)
> > +{
> > + struct resource *mem, *ioarea;
> > + struct ssi_dev *ssi_ctrl = NULL;
> > + struct ssi_platform_data *p_data = NULL;
> > + u32 revision = 0;
> > + int err = 0;
> > +
> > +
> > + if ((pd == NULL) || (pd->dev.platform_data == NULL)) {
> > + pr_err(LOG_NAME "No device/platform_data found on "
> > + "ssi device\n");
> > + return -ENODEV;
> > + }
>
> aff... pd will never be NULL if this driver is probing. I'd rather:
>
> struct ssi_platform_data *pdata = pd->dev.platform_data;
>
> if (!pdata) {
> error messages goes here
> }
>
> > +
> > + ssi_ctrl = kzalloc(sizeof(*ssi_ctrl), GFP_KERNEL);
> > + if (ssi_ctrl == NULL) {
> > + dev_err(&pd->dev, "Could not allocate memory for"
> > + " struct ssi_dev\n");
> > + return -ENOMEM;
> > + }
> > +
> > + p_data = (struct ssi_platform_data *) pd->dev.platform_data;
>
> no cast needed.
>
> > + p_data->ssi_ctrl = ssi_ctrl;
>
> hell no. platform_set_drvdata(pd, ssi_ctrl);
>
> > +
> > + mem = platform_get_resource(pd, IORESOURCE_MEM, 0);
> > + if (!mem) {
> > + dev_err(&pd->dev, "SSI device does not have "
> > + "SSI IO memory region information\n");
> > + err = -ENODEV;
> > + goto rback5;
> > + }
> > +
> > + err = ssi_controller_init(pd);
> > + if (err < 0) {
> > + dev_err(&pd->dev, "Could not initialize ssi controller:"
> > + " %d\n", err);
> > + goto rback5;
> > + }
> > +
> > + ioarea = request_mem_region(mem->start, (mem->end - mem->start) + 1,
> > + pd->dev.bus_id);
> > + if (!ioarea) {
> > + dev_err(&pd->dev, "Unable to request SSI IO memory "
> > + "region\n");
> > + err = -EBUSY;
> > + goto rollback4;
> > + }
> > +
> > + ssi_ctrl->base = (void __iomem *)mem->start;
>
> afff... this is terrible. Use ioremap();
>
> > +
> > + clk_enable(ssi_ctrl->ssi_clk);
> > +
> > + err = request_ssi_irqs(pd);
> > + if (err < 0)
> > + goto rollback1;
> > +
> > + err = request_ssi_gdd_irq(pd);
> > + if (err < 0)
> > + goto rollback2;
> > +
> > + err = ssi_softreset(ssi_ctrl);
> > + if (err < 0)
> > + goto rollback3;
> > +
> > + /* Set default PM settings */
> > + ssi_outl((SSI_AUTOIDLE | SSI_SIDLEMODE_SMART | SSI_MIDLEMODE_SMART),
> > + ssi_ctrl->base, SSI_SYS_SYSCONFIG_REG);
> > + ssi_outl(SSI_CLK_AUTOGATING_ON, ssi_ctrl->base, SSI_GDD_GCR_REG);
> > +
> > + set_ssi_ports_default(pd);
> > +
> > + /* Gather info from registers for the driver.(REVISION) */
> > + revision = ssi_inl(ssi_ctrl->base, SSI_SYS_REVISION_REG);
> > + dev_info(&pd->dev, "SSI Hardware REVISION %d.%d\n",
> > + (revision & SSI_REV_MAJOR) >> 4, (revision & SSI_REV_MINOR));
> > +
> > + err = register_ssi_devices(pd);
> > + if (err < 0)
> > + goto rollback3;
> > +
> > + clk_disable(ssi_ctrl->ssi_clk);
> > +
> > + return err;
> > +
> > +rollback3:
> > + free_ssi_gdd_irq(ssi_ctrl);
> > +rollback2:
> > + free_ssi_irqs(ssi_ctrl);
> > +rollback1:
> add iounmap() here
> > + release_mem_region(mem->start, mem->end - mem->start + 1);
> > + clk_disable(ssi_ctrl->ssi_clk);
> > +rollback4:
> > + ssi_controller_exit(pd);
> > +rback5:
> > + kfree(ssi_ctrl);
> > + return err;
> > +}
> > +
> > +static void __exit close_all_ch(struct ssi_dev *ssi_ctrl)
> > +{
> > + struct ssi_port *ssi_p;
> > + unsigned int port;
> > + unsigned int ch;
> > +
> > + for (port = 0; port < ssi_ctrl->max_p; port++) {
> > + ssi_p = &ssi_ctrl->ssi_port[port];
> > + for (ch = 0; ch < ssi_p->max_ch; ch++)
> > + ssi_close(ssi_p->ssi_channel[ch].dev);
> > + }
> > +}
> > +
> > +static int __exit ssi_remove(struct platform_device *pd)
> > +{
> > + struct resource *mem;
> > + struct ssi_platform_data *p_data =
> > + (struct ssi_platform_data *) pd->dev.platform_data;
> > + struct ssi_dev *ssi_ctrl = p_data->ssi_ctrl;
>
> This should ssi_ctrl = platform_get_drvdata(pd);
>
> > +
> > + close_all_ch(ssi_ctrl);
> > + free_ssi_gdd_irq(ssi_ctrl);
> > + free_ssi_irqs(ssi_ctrl);
> > + mem = platform_get_resource(pd, IORESOURCE_MEM, 0);
> > + if (mem)
> > + release_mem_region(mem->start, mem->end - mem->start + 1);
>
> when you add proper ioremap(), add iounmap here.
>
> > + ssi_controller_exit(pd);
> > + kfree(ssi_ctrl);
> > +
> > + return 0;
> > +}
> > +
> > +static struct platform_driver ssi_pdriver = {
> > + .probe = ssi_probe,
> > + .remove = __exit_p(ssi_remove),
> > + .driver = {
> > + .name = "omap_ssi",
> > + .owner = THIS_MODULE,
> > + }
> > +};
> > +
> > +static int __init ssi_driver_init(void)
> > +{
> > + int err = 0;
> > +
> > + pr_info("SSI DRIVER Version " SSI_DRIVER_VERSION "\n");
> > +
> > + ssi_bus_init();
> > + err = platform_driver_probe(&ssi_pdriver, ssi_probe);
> > + if (err < 0) {
> > + pr_err(LOG_NAME "Platform DRIVER register FAILED: %d\n", err);
> > + ssi_bus_exit();
> > + return err;
> > + }
> > +
> > + return 0;
>
> return platform_driver_register(&ssi_pdriver);
> should be enough.
>
> > +}
> > +
> > +static void __exit ssi_driver_exit(void)
> > +{
> > + ssi_bus_exit();
> > + platform_driver_unregister(&ssi_pdriver);
> > +
> > + pr_info("SSI DRIVER removed\n");
> > +}
> > +
> > +module_init(ssi_driver_init);
> > +module_exit(ssi_driver_exit);
> > +
> > +MODULE_ALIAS("platform:omap_ssi");
> > +MODULE_AUTHOR(SSI_DRIVER_AUTHOR);
> > +MODULE_DESCRIPTION(SSI_DRIVER_DESC);
> > +MODULE_LICENSE("GPL");
> > diff --git a/drivers/misc/ssi/ssi_driver.h b/drivers/misc/ssi/ssi_driver.h
> > new file mode 100644
> > index 0000000..3c6d849
> > --- /dev/null
> > +++ b/drivers/misc/ssi/ssi_driver.h
> > @@ -0,0 +1,211 @@
> > +/*
> > + * ssi_driver.h
> > + *
> > + * Header file for the SSI driver low level interface.
> > + *
> > + * Copyright (C) 2007-2008 Nokia Corporation. All rights reserved.
> > + *
> > + * Contact: Carlos Chinea <[email protected]>
> > + *
> > + * This program is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU General Public License
> > + * version 2 as published by the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope that it will be useful, but
> > + * WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> > + * General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU General Public License
> > + * along with this program; if not, write to the Free Software
> > + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
> > + * 02110-1301 USA
> > + */
> > +
> > +#ifndef __SSI_DRIVER_H__
> > +#define __SSI_DRIVER_H__
> > +
> > +#include <linux/module.h>
> > +#include <linux/init.h>
> > +#include <linux/clk.h>
> > +#include <linux/ioport.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/irq.h>
> > +#include <linux/spinlock.h>
> > +#include <linux/io.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/gpio.h>
> > +
> > +#include <mach/ssi/ssi_reg_common.h>
> > +#include <mach/ssi/ssi_sys_reg.h>
> > +#include <mach/ssi/ssi_ssr_reg.h>
> > +#include <mach/ssi/ssi_sst_reg.h>
> > +#include <mach/ssi/ssi_gdd_reg.h>
> > +
> > +#include <linux/ssi_driver_if.h>
> > +
> > +#define SSI_DRIVER_VERSION "1.1-rc2"
> > +#define SSI_DRIVER_AUTHOR "Carlos Chinea / Nokia"
> > +#define SSI_DRIVER_DESC "Synchronous Serial Interface Driver"
> > +#define SSI_DRIVER_LINCESE "GPL"
> > +#define SSI_DRIVER_NAME "ssi_driver"
> > +
> > +#define SSI_DEVICE_NAME "ssi_device"
>
> these should be in the C-file. Nobody needs to access them
>
> > +
> > +/* 10 ms */
> > +#define SSI_RESETDONE_TIMEOUT 10
> > +/* Let's retry 20 times.=>20x10 ms=200 ms */
> > +#define SSI_RESETDONE_RETRIES 20
> > +
> > +/* Channel states */
> > +#define SSI_CH_OPEN 0x01
> > +
> > +/*
> > + * The number of channels to use by the driver in the ports, or the highest
> > + * port channel number (+1) used. (MAX:8)
> > + */
> > +#define SSI_PORT_MAX_CH 4
> > +/* Number of logical channel in GDD */
> > +#define SSI_NUM_LCH 8
> > +
> > +#define LOG_NAME "OMAP SSI: "
> > +#define SSI_PREFIX "ssi:"
> > +
> > +/*
> > + * Callbacks use by the SSI upper layer (SSI protocol) to receive data
> > + * from the port channels.
> > + */
> > +struct ssi_channel_ops {
> > + void (*write_done) (struct ssi_device *dev);
> > + void (*read_done) (struct ssi_device *dev);
> > +};
> > +
> > +struct ssi_data {
> > + /* Pointer to the data to be sent/received */
> > + u32 *addr;
> > + /*
> > + * Number of words to be sent or space reserved for data to be
> > + * received.
> > + */
> > + unsigned int size;
> > + /* Holds GDD logical channed number */
> > + int lch;
> > +};
> > +
> > +struct ssi_channel {
> > + struct ssi_channel_ops ops;
> > + struct ssi_data read_data;
> > + struct ssi_data write_data;
> > + struct ssi_port *ssi_port;
> > + u8 flags;
> > + u8 channel_number;
> > + spinlock_t ssi_ch_lock;
> > + struct ssi_device *dev;
> > + void *priv;
> > +};
> > +
> > +/* Holds information related to SSI port */
> > +struct ssi_port {
> > + struct ssi_channel ssi_channel[SSI_PORT_MAX_CH];
> > + struct ssi_dev *ssi_controller;
> > + u8 port_number;
> > + u8 max_ch;
> > + u8 n_irq; /* IRQ0 or IRQ1 */
> > + int irq /* Actual IRQ number */;
> > + spinlock_t lock;
> > + struct tasklet_struct ssi_tasklet;
> > +};
> > +
> > +/*
> > + * Struct definition to hold information about the clocks, ssi controller
> > + * and the ssi ports.
> > + */
> > +struct ssi_dev {
> > + /* Holds reference to PORT 1 (and PORT2 if defined) */
> > + struct ssi_port ssi_port[SSI_MAX_PORTS];
> > + int id;
> > + u8 flags;
> > + u8 max_p;
> > + struct clk *ssi_clk;
> > + void __iomem *base;
> > + spinlock_t lock;
> > + int gdd_irq;
> > + struct tasklet_struct ssi_gdd_tasklet;
> > + struct platform_device *pdev;
> > +};
> > +
> > +/* SSI Bus */
> > +struct ssi_port_event {
> > + struct ssi_port *ssi_port;
> > + unsigned int event;
> > + void *priv;
> > +};
> > +extern struct bus_type ssi_bus_type;
> > +
> > +int ssi_port_event_handler(struct ssi_port *p, unsigned int event, void *arg);
> > +int ssi_bus_init(void);
> > +void ssi_bus_exit(void);
> > +/* End SSI Bus */
> > +
> > +int ssi_driver_read_interrupt(struct ssi_channel *ssi_channel, u32 *data);
> > +int ssi_driver_write_interrupt(struct ssi_channel *ssi_channel, u32 *data);
> > +int ssi_driver_read_dma(struct ssi_channel *ssi_channel, u32 *data,
> > + unsigned int count);
> > +int ssi_driver_write_dma(struct ssi_channel *ssi_channel, u32 *data,
> > + unsigned int count);
> > +
> > +void ssi_driver_cancel_write_interrupt(struct ssi_channel *ch);
> > +void ssi_driver_cancel_read_interrupt(struct ssi_channel *ch);
> > +void ssi_driver_cancel_write_dma(struct ssi_channel *ch);
> > +void ssi_driver_cancel_read_dma(struct ssi_channel *ch);
> > +
> > +irqreturn_t ssi_mpu_handler(int irq, void *ssi_port);
> > +irqreturn_t ssi_gdd_mpu_handler(int irq, void *ssi_controller);
> > +
> > +void do_ssi_tasklet(unsigned long ssi_port);
> > +void do_ssi_gdd_tasklet(unsigned long device);
> > +
> > +static inline u32 ssi_inl(void __iomem *base, u32 offset)
> > +{
> > + return inl(OMAP2_IO_ADDRESS(base + offset));
> > +}
> > +
> > +static inline void ssi_outl(u32 data, void __iomem *base, u32 offset)
> > +{
> > + outl(data, OMAP2_IO_ADDRESS(base + offset));
> > +}
> > +
> > +static inline void ssi_outl_or(u32 data, void __iomem *base, u32 offset)
> > +{
> > + u32 tmp = ssi_inl(base, offset);
> > + ssi_outl((tmp | data), base, offset);
> > +}
> > +
> > +static inline void ssi_outl_and(u32 data, void __iomem *base, u32 offset)
> > +{
> > + u32 tmp = ssi_inl(base, offset);
> > + ssi_outl((tmp & data), base, offset);
> > +}
> > +
> > +static inline u16 ssi_inw(void __iomem *base, u32 offset)
> > +{
> > + return inw(OMAP2_IO_ADDRESS(base + offset));
> > +}
> > +
> > +static inline void ssi_outw(u16 data, void __iomem *base, u32 offset)
> > +{
> > + outw(data, OMAP2_IO_ADDRESS(base + offset));
> > +}
> > +
> > +static inline void ssi_outw_or(u16 data, void __iomem *base, u32 offset)
> > +{
> > + u16 tmp = ssi_inw(base, offset);
> > + ssi_outw((tmp | data), base, offset);
> > +}
> > +
> > +static inline void ssi_outw_and(u16 data, void __iomem *base, u32 offset)
> > +{
> > + u16 tmp = ssi_inw(base, offset);
> > + ssi_outw((tmp & data), base, offset);
> > +}
> > +#endif
> > diff --git a/drivers/misc/ssi/ssi_driver_bus.c b/drivers/misc/ssi/ssi_driver_bus.c
> > new file mode 100644
> > index 0000000..6a07ee0
> > --- /dev/null
> > +++ b/drivers/misc/ssi/ssi_driver_bus.c
> > @@ -0,0 +1,192 @@
> > +/*
> > + * ssi_driver_bus.c
> > + *
> > + * Implements SSI bus, device and driver interface.
> > + *
> > + * Copyright (C) 2007-2008 Nokia Corporation. All rights reserved.
> > + *
> > + * Contact: Carlos Chinea <[email protected]>
> > + *
> > + * This program is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU General Public License
> > + * version 2 as published by the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope that it will be useful, but
> > + * WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> > + * General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU General Public License
> > + * along with this program; if not, write to the Free Software
> > + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
> > + * 02110-1301 USA
> > + */
> > +#include <linux/device.h>
> > +#include "ssi_driver.h"
> > +
> > +/* LDM. defintions for the ssi bus, ssi device, and ssi_device driver */
> > +struct bus_type ssi_bus_type;
> > +
> > +static ssize_t modalias_show(struct device *dev, struct device_attribute *a,
> > + char *buf)
> > +{
> > + return snprintf(buf, BUS_ID_SIZE + 1, "%s%s\n", SSI_PREFIX,
> > + dev->bus_id);
> > +}
> > +
> > +static struct device_attribute ssi_dev_attrs[] = {
> > + __ATTR_RO(modalias),
> > + __ATTR_NULL,
> > +};
> > +
> > +static int ssi_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
> > +{
> > + add_uevent_var(env, "MODALIAS=%s%s", SSI_PREFIX, dev->bus_id);
> > + return 0;
> > +}
> > +
> > +/* NOTE: Function called in interrupt context */
> > +static int ssi_e_handler(struct device_driver *drv, void *p_event)
> > +{
> > + struct ssi_port_event *event = (struct ssi_port_event *)p_event;
> > + struct ssi_device_driver *ssi_drv = to_ssi_device_driver(drv);
> > + struct ssi_port *p = event->ssi_port;
> > +
> > + BUG_ON(p_event == NULL);
> > +
> > + if ((ssi_drv->port_event) &&
> > + (test_bit(event->event, &ssi_drv->event_mask)) &&
> > + ((p->ssi_controller->id == -1) ||
> > + (test_bit(p->ssi_controller->id, &ssi_drv->ctrl_mask))) &&
> > + (ssi_drv->ch_mask[p->port_number - 1] != 0)) {
> > +
> > + (*ssi_drv->port_event)(p->ssi_controller->id, p->port_number,
> > + event->event, event->priv);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +int ssi_port_event_handler(struct ssi_port *p, unsigned int event, void *arg)
> > +{
> > + int err = 0;
> > + struct ssi_port_event p_ev = {
> > + .ssi_port = p,
> > + .event = event,
> > + .priv = arg
> > + };
> > +
> > + BUG_ON(p == NULL);
> > +
> > + err = bus_for_each_drv(&ssi_bus_type, NULL, &p_ev, ssi_e_handler);
> > +
> > + return err;
> > +}
> > +
> > +static int ssi_bus_match(struct device *device, struct device_driver *driver)
> > +{
> > + struct ssi_device *dev = to_ssi_device(device);
> > + struct ssi_device_driver *drv = to_ssi_device_driver(driver);
> > +
> > + if (!test_bit(dev->n_ctrl, &drv->ctrl_mask))
> > + return 0;
> > +
> > + if (!test_bit(dev->n_ch, &drv->ch_mask[dev->n_p]))
> > + return 0;
> > +
> > + return 1;
> > +}
> > +
> > +int ssi_bus_unreg_dev(struct device *device, void *p)
> > +{
> > + device->release(device);
> > + device_unregister(device);
> > +
> > + return 0;
> > +}
> > +
> > +int __init ssi_bus_init(void)
> > +{
> > +

remove this extra line

> > + return bus_register(&ssi_bus_type);
> > +

remove this extra line

> > +}
> > +
> > +void ssi_bus_exit(void)
> > +{
> > + bus_for_each_dev(&ssi_bus_type, NULL, NULL, ssi_bus_unreg_dev);
> > + bus_unregister(&ssi_bus_type);
> > +}
> > +
> > +static int ssi_driver_probe(struct device *dev)
> > +{
> > + struct ssi_device_driver *drv = to_ssi_device_driver(dev->driver);
int ret;

if (!drv->probe) /* note if you add MODULE_DEVICE_TABLE test here !drv->id_table */
return -ENODEV;

I think would be nice to save a reference of driver inside ssi_device,
so you would:

to_ssi_device(dev)->driver = drv;
dev_dbg(dev, "probe\n");

ret = driver->probe(to_ssi_device(dev));

if (ret)
to_ssi_device(dev)->driver = NULL

return ret;

> > +}
> > +
> > +static int ssi_driver_remove(struct device *dev)
> > +{
> > + struct ssi_device_driver *drv = to_ssi_device_driver(dev->driver);
int ret;

if (!dev->driver)
return 0;

drv = to_ssi_device_driver(dev->driver);
if (drv->remove) {
dev_dbg(dev, "remove\n");
ret = drv->remove(to_ssi_device(dev));
} else {
dev->driver = NULL;
ret = 0;
}

if (ret == 0)
to_sse_device(dev)->driver = NULL;

return ret;
> > +}
> > +
> > +static int ssi_driver_suspend(struct device *dev, pm_message_t mesg)
> > +{
> > + struct ssi_device_driver *drv = to_ssi_device_driver(dev->driver);
> > +
> > + return drv->suspend(to_ssi_device(dev), mesg);
> > +}
> > +
> > +static int ssi_driver_resume(struct device *dev)
> > +{
> > + struct ssi_device_driver *drv = to_ssi_device_driver(dev->driver);
> > +
> > + return drv->resume(to_ssi_device(dev));

you need to be careful here. Try something like:

if (!dev->driver)
return 0;

drv = to_ssi_device_driver(dev->driver);

if (!drv->suspend)
return 0;

return driver->suspend(to_ssi_device(dev), msg);

ditto to suspend

> > +}
> > +
> > +struct bus_type ssi_bus_type = {
> > + .name = "ssi",
> > + .dev_attrs = ssi_dev_attrs,
> > + .match = ssi_bus_match,
> > + .uevent = ssi_bus_uevent,
>
> tabify these
>
> .name = "ssi",
> .dev_attrs = ssi_dev_attrs,
> .match = ssi_bus_match,
> .uevent = ssi_bus_uevent,

add suspend, resume, probe and remove to ssi_bus_type and remove what
you have in register_ssi_driver.

> > +int register_ssi_driver(struct ssi_device_driver *driver)
> > +{
> > + int ret = 0;
> > +
> > + BUG_ON(driver == NULL);
>
> don't bug, just return. BUG will oops the kernel. Returning would be
> more appropriate since what needs fix is the driver trying to register
> not the bus driver.
>
> > +
> > + driver->driver.bus = &ssi_bus_type;

--- remove from here

> > + if (driver->probe)
> > + driver->driver.probe = ssi_driver_probe;
> > + if (driver->remove)
> > + driver->driver.remove = ssi_driver_remove;
> > + if (driver->suspend)
> > + driver->driver.suspend = ssi_driver_suspend;
> > + if (driver->resume)
> > + driver->driver.resume = ssi_driver_resume;
> > +

--- to here.

> > + ret = driver_register(&driver->driver);

would be nice to get a success message if ret == 0:

if (ret == 0)
pr_debug("ssi: driver %s registered\n", driver->driver.name);

> > +
> > + return ret;
> > +}
> > +EXPORT_SYMBOL(register_ssi_driver);
> > +
> > +/**
> > + * unregister_ssi_driver - Unregister SSI device driver
> > + * @driver - reference to the SSI device driver.
> > + */
> > +void unregister_ssi_driver(struct ssi_device_driver *driver)
> > +{
> > + BUG_ON(driver == NULL);
>
> ditto.
>
> > +
> > + driver_unregister(&driver->driver);

same here:

pr_debug("ssi: driver %s unregistered\n", driver->driver.name);

> > +}
> > +EXPORT_SYMBOL(unregister_ssi_driver);
> > diff --git a/drivers/misc/ssi/ssi_driver_dma.c b/drivers/misc/ssi/ssi_driver_dma.c
> > new file mode 100644
> > index 0000000..2524a12
> > --- /dev/null
> > +++ b/drivers/misc/ssi/ssi_driver_dma.c
> > @@ -0,0 +1,406 @@
> > +/*
> > + * ssi_driver_dma.c
> > + *
> > + * Implements SSI low level interface driver functionality with DMA support.
> > + *
> > + * Copyright (C) 2007-2008 Nokia Corporation. All rights reserved.
> > + *
> > + * Contact: Carlos Chinea <[email protected]>
> > + *
> > + * This program is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU General Public License
> > + * version 2 as published by the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope that it will be useful, but
> > + * WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> > + * General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU General Public License
> > + * along with this program; if not, write to the Free Software
> > + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
> > + * 02110-1301 USA
> > + */
> > +#include <linux/dma-mapping.h>
> > +#include "ssi_driver.h"
> > +
> > +#define SSI_SYNC_WRITE 0
> > +#define SSI_SYNC_READ 1
> ^^ trailing whitespaces
> > +

the following variables and functions, etc please prepend them with ssi_
to avoid possible namespace conflicts.

also, fix the comment style to be kerneldoc style:

/**
* function name - small description
*
* @parameter1: small description
* @parameter2: small description
* @parameterN: small description
*
* Here you put a long description of the function
* and what it really does. Just don't extend too much
* and don't translate C-code into english, just give
* information on what's the main purpose for that function
* and anything you think is really valid to mention.
*
* Returns 0 on success or negative errno
*/

of course the Returns blabla will have to change according to what the
function really returns: channel number, port number, sync type, etc.

> > +static unsigned char sync_table[2][2][8] = {
> > + {
> > + {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08},
> > + {0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x00}
> > + },
> > + {
>
> }, { would look better
>
> > + {0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17},
> > + {0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F}
> > + }
> > +};
> > +
> > +static unsigned int get_sync_type(unsigned int sync)
> > +{
> > + return (sync & 0x10) ? SSI_SYNC_READ : SSI_SYNC_WRITE;
> > +}
> > +
> > +static unsigned int get_sync_port(unsigned int sync)
> > +{
> > + if (((sync >= 0x01) && (sync <= 0x08)) ||
> > + ((sync >= 0x10) && (sync <= 0x17)))
> > + return 1;
> > + else if (((sync >= 0x09) && (sync <= 0x0F)) ||
> > + ((sync >= 0x18) && (sync <= 0x1E)))
> > + return 2;
> > + else
> > + return 3;

what's the main idea here? you pass sync and it's return the port number ??
this really looks odd. I wanna understand this better and let's try to
find a better solution, shall we ? :-)

> > +}
> > +
> > +static unsigned int get_sync_channel(unsigned int sync)
> > +{
> > + if ((sync == 0x00) || (sync == 0x1F))
> > + return 8;
> > +
> > + if (sync & 0x10)
> > + return (sync & 0x0F) % 8;
> > + else
> > + return (sync - 1) % 8;

ditto

> > +}
> > +
> > +static unsigned int get_sync(unsigned int port,
> > + unsigned int channel, unsigned int type)
> > +{
> > + if ((port == 0) || (port > SSI_MAX_PORTS) ||
> > + (channel >= SSI_PORT_MAX_CH) || (type > SSI_SYNC_READ))
> > + return 0x00;
> > +
> > + return sync_table[type][port - 1][channel];

ditto

> > +}
> > +
> > +static void rst_ch_read(struct ssi_dev *ssi_ctrl,
> > + unsigned int n_p, unsigned int n_ch)
> > +{
> > + struct ssi_channel *ch =
> > + &ssi_ctrl->ssi_port[n_p - 1].ssi_channel[n_ch];
> > +
> > + ch->read_data.addr = NULL;
> > + ch->read_data.size = 0;
> > + ch->read_data.lch = -1;
> > +}
> > +
> > +static void rst_ch_write(struct ssi_dev *ssi_ctrl,
> > + unsigned int n_p, unsigned int n_ch)
> > +{
> > + struct ssi_channel *ch =
> > + &ssi_ctrl->ssi_port[n_p - 1].ssi_channel[n_ch];
> > +
> > + ch->write_data.addr = NULL;
> > + ch->write_data.size = 0;
> > + ch->write_data.lch = -1;
> > +}
> > +
> > +/*
> > + * get_free_lch - Get a free GDD(DMA)logical channel
> > + * @ssi_ctrl- SSI controller of the GDD.
> > + *
> > + * Needs to be called holding the gdd controller lock
> > + */
> > +static unsigned int get_free_lch(struct ssi_dev *ssi_ctrl)
> > +{
> > + unsigned int enable_reg;
> > + unsigned int lch = 0;
> > +
> > + enable_reg = ssi_inl(ssi_ctrl->base, SSI_SYS_GDD_MPU_IRQ_ENABLE_REG);
> > + while ((lch < SSI_NUM_LCH) && (enable_reg & SSI_GDD_LCH(lch)))
> > + lch++;
> > +
> > + return lch;
> > +}
> > +
> > +/*
> > + * ssi_driver_write_dma - Program GDD [DMA] to write data from memory to
> > + * the ssi channel buffer.
> > + * @ssi_channel - pointer to the ssi_channel to write data to.
> > + * @data - 32-bit word pointer to the data.
> > + * @size - Number of 32bit words to be transfered.
> > + *
> > + * ssi_controller lock must be hold before calling this function.

s/hold/held

> > + */
> > +int ssi_driver_write_dma(struct ssi_channel *ssi_channel, u32 *data,
> > + unsigned int size)
> > +{
> > + struct ssi_dev *ssi_ctrl = ssi_channel->ssi_port->ssi_controller;
> > + void __iomem *base = ssi_ctrl->base;
> > + unsigned int port = ssi_channel->ssi_port->port_number;
> > + unsigned int channel = ssi_channel->channel_number;
> > + unsigned int sync;
> > + int lch;
> > + dma_addr_t dma_data;
> > + u32 s_addr;
> > + u16 tmp;
> > +
> > + if ((size < 1) || (data == NULL))
> > + return -EINVAL;
> > +
> > + clk_enable(ssi_ctrl->ssi_clk);
> > +
> > + lch = get_free_lch(ssi_ctrl);
> > + if (lch >= SSI_NUM_LCH) {
> > + dev_err(&ssi_ctrl->pdev->dev, "No free GDD logical "
> > + "channels.\n");
> > + clk_disable(ssi_ctrl->ssi_clk);
> > + return -EBUSY; /* No free GDD logical channels. */
> > + }
> > + /* NOTE: Gettting a free gdd logical channel and
> > + * reserve it must be done atomicaly. */
> > + ssi_channel->write_data.lch = lch;
> > +
> > + sync = get_sync(port, channel, SSI_SYNC_WRITE);
> > + dma_data = dma_map_single(NULL, data, size * 4, DMA_TO_DEVICE);
> > + dma_sync_single(NULL, dma_data, size * 4, DMA_TO_DEVICE);
> > +
> > + tmp = SSI_SRC_SINGLE_ACCESS0 |
> > + SSI_SRC_MEMORY_PORT |
> > + SSI_DST_SINGLE_ACCESS0 |
> > + SSI_DST_PERIPHERAL_PORT |
> > + SSI_DATA_TYPE_S32;
> > + ssi_outw(tmp, base, SSI_GDD_CSDP_REG(lch));
> > + tmp = SSI_SRC_AMODE_POSTINC | SSI_DST_AMODE_CONST | sync;
> > + ssi_outw(tmp, base, SSI_GDD_CCR_REG(lch));
> > + ssi_outw((SSI_BLOCK_IE | SSI_TOUT_IE), base, SSI_GDD_CICR_REG(lch));
> > + s_addr = (u32)base + SSI_SST_BUFFER_CH_REG(port, channel);
> > + ssi_outl(s_addr, base, SSI_GDD_CDSA_REG(lch));
> > + ssi_outl(dma_data, base, SSI_GDD_CSSA_REG(lch));
> > + ssi_outw(size, base, SSI_GDD_CEN_REG(lch));
> > + ssi_outl_or(SSI_GDD_LCH(lch), base, SSI_SYS_GDD_MPU_IRQ_ENABLE_REG);
> > + ssi_outw_or(SSI_CCR_ENABLE, base, SSI_GDD_CCR_REG(lch));

a bit of spacing up here will increase readability.

> > +
> > + return 0;
> > +}
> > +
> > +/*
> > + * ssi_driver_read_dma - Program GDD [DMA] to write data to memory from
> > + * the ssi channel buffer.
> > + * @ssi_channel - pointer to the ssi_channel to read data from.
> > + * @data - 32-bit word pointer where to store the incoming data.
> > + * @size - Number of 32bit words to be transfered to the buffer.
> > + *
> > + * ssi_controller lock must be hold before calling this function.
> > + */
> > +int ssi_driver_read_dma(struct ssi_channel *ssi_channel, u32 *data,
> > + unsigned int count)
> > +{
> > + struct ssi_dev *ssi_ctrl = ssi_channel->ssi_port->ssi_controller;
> > + void __iomem *base = ssi_ctrl->base;
> > + unsigned int port = ssi_channel->ssi_port->port_number;
> > + unsigned int channel = ssi_channel->channel_number;
> > + unsigned int sync;
> > + unsigned int lch;
> > + dma_addr_t dma_data;
> > + u32 d_addr;
> > + u16 tmp;
> > +
> > + clk_enable(ssi_ctrl->ssi_clk);
> > + lch = get_free_lch(ssi_ctrl);
> > + if (lch >= SSI_NUM_LCH) {
> > + dev_err(&ssi_ctrl->pdev->dev, "No free GDD logical "
> > + "channels.\n");
> > + clk_disable(ssi_ctrl->ssi_clk);
> > + return -EBUSY; /* No free GDD logical channels. */
> > + }
> > + /*
> > + * NOTE: Gettting a free gdd logical channel and
> > + * reserve it must be done atomicaly.
> > + */
> > + ssi_channel->read_data.lch = lch;
> > +
> > + sync = get_sync(port, channel, SSI_SYNC_READ);
> > +
> > + dma_data = dma_map_single(NULL, data, count * 4, DMA_FROM_DEVICE);
> > +
> > + tmp = SSI_DST_SINGLE_ACCESS0 |
> > + SSI_DST_MEMORY_PORT |
> > + SSI_SRC_SINGLE_ACCESS0 |
> > + SSI_SRC_PERIPHERAL_PORT |
> > + SSI_DATA_TYPE_S32;
> > + ssi_outw(tmp, base, SSI_GDD_CSDP_REG(lch));
> > + tmp = SSI_DST_AMODE_POSTINC | SSI_SRC_AMODE_CONST | sync;
> > + ssi_outw(tmp, base, SSI_GDD_CCR_REG(lch));
> > + ssi_outw((SSI_BLOCK_IE | SSI_TOUT_IE), base, SSI_GDD_CICR_REG(lch));
> > + d_addr = (u32)base + SSI_SSR_BUFFER_CH_REG(port, channel);

don't keep casting the addresses, find a better solution. If you need to
keep casting them around between void __iomem * and some unsigned, your
code needs attention. Ditto to all other occurrencies of this.

> > + ssi_outl(d_addr, base, SSI_GDD_CSSA_REG(lch));
> > + ssi_outl((u32)dma_data, base, SSI_GDD_CDSA_REG(lch));
> > + ssi_outw(count, base, SSI_GDD_CEN_REG(lch));

ditto.

> > +
> > + ssi_outl_or(SSI_GDD_LCH(lch), base, SSI_SYS_GDD_MPU_IRQ_ENABLE_REG);
> > + ssi_outw_or(SSI_CCR_ENABLE, base, SSI_GDD_CCR_REG(lch));
> > +
> > + return 0;
> > +}
> > +
> > +void ssi_driver_cancel_write_dma(struct ssi_channel *ssi_ch)
> > +{
> > + int lch = ssi_ch->write_data.lch;
> > + unsigned int port = ssi_ch->ssi_port->port_number;
> > + unsigned int channel = ssi_ch->channel_number;
> > + struct ssi_dev *ssi_ctrl = ssi_ch->ssi_port->ssi_controller;
> > + u32 ccr;
> > +
> > + if (lch < 0)
> > + return;
> > +
> > + clk_enable(ssi_ctrl->ssi_clk);
> > + ccr = ssi_inw(ssi_ctrl->base, SSI_GDD_CCR_REG(lch));
> > + if (!(ccr & SSI_CCR_ENABLE)) {
> > + dev_dbg(&ssi_ch->dev->device, LOG_NAME "Write cancel on not "
> > + "enabled logical channel %d CCR REG 0x%08X\n", lch, ccr);
> > + clk_disable(ssi_ctrl->ssi_clk);
> > + return;
> > + }
> > +
> > + ssi_outw_and(~SSI_CCR_ENABLE, ssi_ctrl->base, SSI_GDD_CCR_REG(lch));
> > + ssi_outl_and(~SSI_GDD_LCH(lch), ssi_ctrl->base,
> > + SSI_SYS_GDD_MPU_IRQ_ENABLE_REG);
> > + ssi_outl(SSI_GDD_LCH(lch), ssi_ctrl->base,
> > + SSI_SYS_GDD_MPU_IRQ_STATUS_REG);
> > +
> > + ssi_outl_and(~NOTFULL(channel), ssi_ctrl->base,
> > + SSI_SST_BUFSTATE_REG(port));
> > +
> > +

any reason why one blank line isn't enough ?

> > + ssi_ch->write_data.addr = NULL;
> > + ssi_ch->write_data.size = 0;
> > + ssi_ch->write_data.lch = -1;
> > + clk_disable(ssi_ctrl->ssi_clk);
> > + clk_disable(ssi_ctrl->ssi_clk);

clk_disable is duplicated.

> > +}
> > +
> > +void ssi_driver_cancel_read_dma(struct ssi_channel *ssi_ch)
> > +{
> > + int lch = ssi_ch->read_data.lch;
> > + struct ssi_dev *ssi_ctrl = ssi_ch->ssi_port->ssi_controller;
> > + unsigned int port = ssi_ch->ssi_port->port_number;
> > + unsigned int channel = ssi_ch->channel_number;
> > + u32 reg;
> > +
> > + if (lch < 0)
> > + return;
> > +
> > + clk_enable(ssi_ctrl->ssi_clk);
> > + reg = ssi_inw(ssi_ctrl->base, SSI_GDD_CCR_REG(lch));
> > + if (!(reg & SSI_CCR_ENABLE)) {
> > + dev_dbg(&ssi_ch->dev->device, LOG_NAME "Read cancel on not "
> > + "enable logical channel %d CCR REG 0x%08X\n", lch, reg);
> > + clk_disable(ssi_ctrl->ssi_clk);
> > + return;
> > + }
> > +
> > + ssi_outw_and(~SSI_CCR_ENABLE, ssi_ctrl->base, SSI_GDD_CCR_REG(lch));
> > + ssi_outl_and(~SSI_GDD_LCH(lch), ssi_ctrl->base,
> > + SSI_SYS_GDD_MPU_IRQ_ENABLE_REG);
> > + ssi_outl(SSI_GDD_LCH(lch), ssi_ctrl->base,
> > + SSI_SYS_GDD_MPU_IRQ_STATUS_REG);
> > +
> > + ssi_outl_and(~NOTEMPTY(channel), ssi_ctrl->base,
> > + SSI_SSR_BUFSTATE_REG(port));
> > +
> > + ssi_ch->read_data.addr = NULL;
> > + ssi_ch->read_data.size = 0;
> > + ssi_ch->read_data.lch = -1;
> > + clk_disable(ssi_ctrl->ssi_clk);
> > + clk_disable(ssi_ctrl->ssi_clk);

ditto.

> > +}
> > +
> > +static void dma_read_cb(struct ssi_dev *ctrl, unsigned int port,
> > + unsigned int channel)

take a few tabs away from the second line.

> > +{
> > + struct ssi_channel *ch = &ctrl->ssi_port[port - 1].ssi_channel[channel];
> > +
> > + ch->ops.read_done(ch->dev);
> > +}
> > +
> > +static void dma_write_cb(struct ssi_dev *ctrl, unsigned int port,
> > + unsigned int channel)

take a few tabs away from the second line.

> > +{
> > + struct ssi_channel *ch = &ctrl->ssi_port[port - 1].ssi_channel[channel];
> > +
> > + ch->ops.write_done(ch->dev);
> > +}
> > +
> > +static void do_gdd_lch(struct ssi_dev *ssi_ctrl, unsigned int gdd_lch)
> > +{
> > + void __iomem *base = ssi_ctrl->base;
> > + unsigned int port;
> > + unsigned int channel;
> > + u32 sync;
> > + u32 gdd_csr;
> > + dma_addr_t dma_h;
> > + size_t size;
> > +
> > + sync = ssi_inw(base, SSI_GDD_CCR_REG(gdd_lch)) & SSI_CCR_SYNC_MASK;
> > + port = get_sync_port(sync);
> > + channel = get_sync_channel(sync);
> > +
> > + spin_lock(&ssi_ctrl->lock);
> > +
> > + ssi_outl_and(~SSI_GDD_LCH(gdd_lch), base,
> > + SSI_SYS_GDD_MPU_IRQ_ENABLE_REG);
> > + gdd_csr = ssi_inw(base, SSI_GDD_CSR_REG(gdd_lch));
> > +
> > + if (!(gdd_csr & SSI_CSR_TOUR)) {
> > + if (get_sync_type(sync) == SSI_SYNC_READ) {
> > + dma_h = ssi_inl(base, SSI_GDD_CDSA_REG(gdd_lch));
> > + size = ssi_inw(base, SSI_GDD_CEN_REG(gdd_lch)) * 4;
> > + dma_sync_single(NULL, dma_h, size, DMA_FROM_DEVICE);
> > + rst_ch_read(ssi_ctrl, port, channel);
> > + spin_unlock(&ssi_ctrl->lock);
> > + dma_read_cb(ssi_ctrl, port, channel);
> > + } else {
> > + rst_ch_write(ssi_ctrl, port, channel);
> > + spin_unlock(&ssi_ctrl->lock);
> > + dma_write_cb(ssi_ctrl, port, channel);
> > + }
> > + } else {
> > + dev_err(&ssi_ctrl->pdev->dev, "Error on GDD transfer "
> > + "on gdd channel %d port %d channel %d\n",
> > + gdd_lch, port, channel);
> > + spin_unlock(&ssi_ctrl->lock);
> > + ssi_port_event_handler(&ssi_ctrl->ssi_port[port - 1],
> > + SSI_EVENT_ERROR, NULL);
> > + }
> > +}
> > +
> > +void do_ssi_gdd_tasklet(unsigned long device)
> > +{
> > + struct ssi_dev *ssi_ctrl = (struct ssi_dev *)device;
> > + void __iomem *base = ssi_ctrl->base;
> > + unsigned int gdd_lch = 0;
> > + u32 status_reg = 0;
> > + u32 lch_served = 0;
> > +
> > + clk_enable(ssi_ctrl->ssi_clk);
> > +
> > + status_reg = ssi_inl(base, SSI_SYS_GDD_MPU_IRQ_STATUS_REG);
> > +
> > + for (gdd_lch = 0; gdd_lch < SSI_NUM_LCH; gdd_lch++) {
> > + if (status_reg & SSI_GDD_LCH(gdd_lch)) {
> > + do_gdd_lch(ssi_ctrl, gdd_lch);
> > + lch_served |= SSI_GDD_LCH(gdd_lch);
> > + clk_disable(ssi_ctrl->ssi_clk);

clk_disable() will be called as many times as this loop executes and the
if condition is met. Fix it.

> > + }
> > + }
> > +
> > + ssi_outl(lch_served, base, SSI_SYS_GDD_MPU_IRQ_STATUS_REG);
> > + clk_disable(ssi_ctrl->ssi_clk);
> > +
> > + enable_irq(ssi_ctrl->gdd_irq);
> > +}
> > +
> > +irqreturn_t ssi_gdd_mpu_handler(int irq, void *ssi_controller)
> > +{
> > + struct ssi_dev *ssi_ctrl = (struct ssi_dev *)ssi_controller;
> > +
> > + tasklet_hi_schedule(&ssi_ctrl->ssi_gdd_tasklet);
> > + disable_irq_nosync(ssi_ctrl->gdd_irq);
> > +
> > + return IRQ_HANDLED;
> > +}
> > diff --git a/drivers/misc/ssi/ssi_driver_if.c b/drivers/misc/ssi/ssi_driver_if.c
> > new file mode 100644
> > index 0000000..385467e
> > --- /dev/null
> > +++ b/drivers/misc/ssi/ssi_driver_if.c
> > @@ -0,0 +1,335 @@
> > +/*
> > + * ssi_driver_if.c
> > + *
> > + * Implements SSI hardware driver interfaces for the upper layers.
> > + *
> > + * Copyright (C) 2007-2008 Nokia Corporation. All rights reserved.
> > + *
> > + * Contact: Carlos Chinea <[email protected]>
> > + *
> > + * This program is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU General Public License
> > + * version 2 as published by the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope that it will be useful, but
> > + * WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> > + * General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU General Public License
> > + * along with this program; if not, write to the Free Software
> > + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
> > + * 02110-1301 USA
> > + */
> > +
> > +#include "ssi_driver.h"
> > +
> > +/**
> > + * ssi_open - open a ssi device channel.
> > + * @dev - Reference to the ssi device channel to be openned.
> > + *
> > + * Returns 0 on success, -EINVAL on bad parameters, -EBUSY if is already opened.
> > + */
> > +int ssi_open(struct ssi_device *dev)
> > +{
> > + struct ssi_channel *ch;
> > + struct ssi_port *port;
> > + struct ssi_dev *ssi_ctrl;
> > +
> > + if (!dev || !dev->ch) {
> > + pr_err(LOG_NAME "Wrong SSI device %p\n", dev);
> > + return -EINVAL;
> > + }
> > +
> > + ch = dev->ch;
> > + if (!ch->ops.read_done || !ch->ops.write_done) {
> > + dev_err(&dev->device, "Trying to open with no callbacks "
> > + "registered\n");
> > + return -EINVAL;
> > + }
> > + port = ch->ssi_port;
> > + ssi_ctrl = port->ssi_controller;
> > + spin_lock_bh(&ssi_ctrl->lock);
> > + if (ch->flags & SSI_CH_OPEN) {
> > + dev_err(&dev->device, "Port %d Channel %d already OPENED\n",
> > + dev->n_p, dev->n_ch);
> > + spin_unlock_bh(&ssi_ctrl->lock);
> > + return -EBUSY;
> > + }
> > + clk_enable(ssi_ctrl->ssi_clk);
> > + ch->flags |= SSI_CH_OPEN;
> > + ssi_outl_or(SSI_ERROROCCURED | SSI_BREAKDETECTED, ssi_ctrl->base,
> > + SSI_SYS_MPU_ENABLE_REG(port->port_number, port->n_irq));
> > + clk_disable(ssi_ctrl->ssi_clk);
> > + spin_unlock_bh(&ssi_ctrl->lock);
> > +
> > + return 0;
> > +}
> > +EXPORT_SYMBOL(ssi_open);
> > +
> > +/**
> > + * ssi_write - write data into the ssi device channel
> > + * @dev - reference to the ssi device channel to write into.
> > + * @data - pointer to a 32-bit word data to be written.
> > + * @count - number of 32-bit word to be written.
> > + *
> > + * Return 0 on sucess, a negative value on failure.
> > + * A success values only indicates that the request has been accepted.

plural or singular ??

> > + * Transfer is only completed when the write_done callback is called.
> > + *
> > + */
> > +int ssi_write(struct ssi_device *dev, u32 *data, unsigned int count)
> > +{
> > + struct ssi_channel *ch;
> > + int err;
> > +
> > + if (unlikely(!dev || !dev->ch || !data || (count <= 0))) {

if someone doesn't meet this conditions they deserve to oops I'd say.
It would avoid badly written drivers.

> > + dev_err(&dev->device, "Wrong paramenters "
> > + "ssi_device %p data %p count %d", dev, data, count);
> > + return -EINVAL;
> > + }
> > + if (unlikely(!(dev->ch->flags & SSI_CH_OPEN))) {
> > + dev_err(&dev->device, "SSI device NOT open\n");
> > + return -EINVAL;
> > + }
> > +
> > + ch = dev->ch;
> > + spin_lock_bh(&ch->ssi_port->ssi_controller->lock);
> > + ch->write_data.addr = data;
> > + ch->write_data.size = count;

how about matching the names ??

> > +
> > + if (count == 1)
> > + err = ssi_driver_write_interrupt(ch, data);
> > + else
> > + err = ssi_driver_write_dma(ch, data, count);
> > +
> > + if (unlikely(err < 0)) {
> > + ch->write_data.addr = NULL;
> > + ch->write_data.size = 0;
> > + }
> > + spin_unlock_bh(&ch->ssi_port->ssi_controller->lock);
> > +
> > + return err;
> > +
> > +}
> > +EXPORT_SYMBOL(ssi_write);
> > +
> > +/**
> > + * ssi_read - read data from the ssi device channel
> > + * @dev - ssi device channel reference to read data from.
> > + * @data - pointer to a 32-bit word data to store the data.
> > + * @count - number of 32-bit word to be stored.
> > + *
> > + * Return 0 on sucess, a negative value on failure.
> > + * A success values only indicates that the request has been accepted.
> > + * Data is only available in the buffer when the read_done callback is called.
> > + *
> > + */
> > +int ssi_read(struct ssi_device *dev, u32 *data, unsigned int count)
> > +{
> > + struct ssi_channel *ch;
> > + int err;
> > +
> > + if (unlikely(!dev || !dev->ch || !data || (count <= 0))) {

ditto.

> > + dev_err(&dev->device, "Wrong paramenters "
> > + "ssi_device %p data %p count %d", dev, data, count);
> > + return -EINVAL;
> > + }
> > + if (unlikely(!(dev->ch->flags & SSI_CH_OPEN))) {
> > + dev_err(&dev->device, "SSI device NOT open\n");
> > + return -EINVAL;
> > + }
> > +
> > + ch = dev->ch;
> > + spin_lock_bh(&ch->ssi_port->ssi_controller->lock);
> > + ch->read_data.addr = data;
> > + ch->read_data.size = count;

how about matching the names ??

> > +
> > + if (count == 1)
> > + err = ssi_driver_read_interrupt(ch, data);
> > + else
> > + err = ssi_driver_read_dma(ch, data, count);
> > +
> > + if (unlikely(err < 0)) {
> > + ch->read_data.addr = NULL;
> > + ch->read_data.size = 0;
> > + }
> > + spin_unlock_bh(&ch->ssi_port->ssi_controller->lock);
> > +
> > + return err;
> > +}
> > +EXPORT_SYMBOL(ssi_read);
> > +
> > +void __ssi_write_cancel(struct ssi_channel *ch)
> > +{
> > + if (ch->write_data.size == 1)
> > + ssi_driver_cancel_write_interrupt(ch);
> > + else if (ch->write_data.size > 1)
> > + ssi_driver_cancel_write_dma(ch);
> > +
> > +}
> > +/**
> > + * ssi_write_cancel - Cancel pending write request.
> > + * @dev - ssi device channel where to cancel the pending write.
> > + *
> > + * write_done() callback will not be called after sucess of this function.
> > + */
> > +void ssi_write_cancel(struct ssi_device *dev)
> > +{
> > + if (unlikely(!dev || !dev->ch)) {
> > + pr_err(LOG_NAME "Wrong SSI device %p\n", dev);
> > + return;
> > + }
> > + if (unlikely(!(dev->ch->flags & SSI_CH_OPEN))) {
> > + dev_err(&dev->device, "SSI device NOT open\n");
> > + return;
> > + }
> > +
> > + spin_lock_bh(&dev->ch->ssi_port->ssi_controller->lock);
> > + __ssi_write_cancel(dev->ch);
> > + spin_unlock_bh(&dev->ch->ssi_port->ssi_controller->lock);
> > +}
> > +EXPORT_SYMBOL(ssi_write_cancel);
> > +
> > +void __ssi_read_cancel(struct ssi_channel *ch)
> > +{
> > + if (ch->read_data.size == 1)
> > + ssi_driver_cancel_read_interrupt(ch);
> > + else if (ch->read_data.size > 1)
> > + ssi_driver_cancel_read_dma(ch);
> > +}
> > +
> > +/**
> > + * ssi_read_cancel - Cancel pending read request.
> > + * @dev - ssi device channel where to cancel the pending read.
> > + *
> > + * read_done() callback will not be called after sucess of this function.
> > + */
> > +void ssi_read_cancel(struct ssi_device *dev)
> > +{
> > + if (unlikely(!dev || !dev->ch)) {
> > + pr_err(LOG_NAME "Wrong SSI device %p\n", dev);
> > + return;
> > + }
> > +
> > + if (unlikely(!(dev->ch->flags & SSI_CH_OPEN))) {
> > + dev_err(&dev->device, "SSI device NOT open\n");
> > + return;
> > + }
> > +
> > + spin_lock_bh(&dev->ch->ssi_port->ssi_controller->lock);
> > + __ssi_read_cancel(dev->ch);
> > + spin_unlock_bh(&dev->ch->ssi_port->ssi_controller->lock);
> > +
> > +}
> > +EXPORT_SYMBOL(ssi_read_cancel);
> > +
> > +/**
> > + * ssi_ioctl - SSI I/O control
> > + * @dev - ssi device channel reference to apply the I/O control
> > + * (or port associated to it)
^ trailing whitespace and you can remove a few tabs from the
second line

> > + * @command - SSI I/O control command
> > + * @arg - parameter associated to the control command. NULL, if no parameter.
> > + *
> > + * Return 0 on sucess, a negative value on failure.
> > + *
> > + */
> > +int ssi_ioctl(struct ssi_device *dev, unsigned int command, void *arg)
> > +{
> > + struct ssi_channel *ch;
> > + struct ssi_dev *ssi_ctrl;
> > + void __iomem *base;
> > + unsigned int port, channel;
> > + u32 wake;
> > + int err = 0;
> > +
> > + if (unlikely((!dev) ||
> > + (!dev->ch) ||
> > + (!dev->ch->ssi_port) ||
> > + (!dev->ch->ssi_port->ssi_controller)) ||
> > + (!(dev->ch->flags & SSI_CH_OPEN))) {
> > + pr_err(LOG_NAME "SSI IOCTL Invalid parameter\n");
> > + return -EINVAL;
> > + }
> > +
> > +

remove one blank line.

> > + ch = dev->ch;
> > + ssi_ctrl = ch->ssi_port->ssi_controller;
> > + port = ch->ssi_port->port_number;
> > + channel = ch->channel_number;
> > + base = ssi_ctrl->base;
> > + clk_enable(ssi_ctrl->ssi_clk);
> > +
> > + switch (command) {
> > + case SSI_IOCTL_WAKE_UP:
> > + /* We only claim once the wake line per channel */
> > + wake = ssi_inl(base, SSI_SYS_WAKE_REG(port));
> > + if (!(wake & SSI_WAKE(channel))) {
> > + clk_enable(ssi_ctrl->ssi_clk);
> > + ssi_outl(SSI_WAKE(channel), base,
> > + SSI_SYS_SET_WAKE_REG(port));
> > + }
> > + break;
> > + case SSI_IOCTL_WAKE_DOWN:
> > + wake = ssi_inl(base, SSI_SYS_WAKE_REG(port));
> > + if ((wake & SSI_WAKE(channel))) {
> > + ssi_outl(SSI_WAKE(channel), base,
> > + SSI_SYS_CLEAR_WAKE_REG(port));
> > + clk_disable(ssi_ctrl->ssi_clk);
> > + }
> > + break;
> > + case SSI_IOCTL_SEND_BREAK:
> > + ssi_outl(1, base, SSI_SST_BREAK_REG(port));
> > + break;
> > + case SSI_IOCTL_WAKE:
> > + if (arg == NULL)
> > + err = -EINVAL;
> > + else
> > + *(u32 *)arg = ssi_inl(base, SSI_SYS_WAKE_REG(port));
> > + break;
> > + default:
> > + err = -ENOIOCTLCMD;
> > + break;
> > + }
> > +
> > + clk_disable(ssi_ctrl->ssi_clk);
> > +
> > + return err;
> > +}
> > +EXPORT_SYMBOL(ssi_ioctl);
> > +
> > +/**
> > + * ssi_close - close given ssi device channel
> > + * @dev - reference to ssi device channel.
> > + */
> > +void ssi_close(struct ssi_device *dev)
> > +{
> > + if (!dev || !dev->ch) {
> > + pr_err(LOG_NAME "Trying to close wrong SSI device %p\n", dev);
> > + return;
> > + }
> > +
> > + spin_lock_bh(&dev->ch->ssi_port->ssi_controller->lock);
> > + if (dev->ch->flags & SSI_CH_OPEN) {
> > + dev->ch->flags &= ~SSI_CH_OPEN;
> > + __ssi_write_cancel(dev->ch);
> > + __ssi_read_cancel(dev->ch);
> > + }
> > + spin_unlock_bh(&dev->ch->ssi_port->ssi_controller->lock);
> > +
> > +}
> > +EXPORT_SYMBOL(ssi_close);
> > +
> > +/**
> > + * ssi_dev_set_cb - register read_done() and write_done() callbacks.
> > + * @dev - reference to ssi device channel where callbacks are associated.
> > + * @r_cb - callback to signal read transfer completed.
> > + * @w_cb - callback to signal write transfer completed.

I'd call them read and write. Or maybe have only one 'complete' and it
handles read and write inside itself, would have to think a bit more
about this.

> > + */
> > +void ssi_dev_set_cb(struct ssi_device *dev, void (*r_cb)(struct ssi_device *dev)
> > + , void (*w_cb)(struct ssi_device *dev))
> > +{
> > + dev->ch->ops.read_done = r_cb;
> > + dev->ch->ops.write_done = w_cb;
> > +}
> > +EXPORT_SYMBOL(ssi_dev_set_cb);
> > diff --git a/drivers/misc/ssi/ssi_driver_int.c b/drivers/misc/ssi/ssi_driver_int.c
> > new file mode 100644
> > index 0000000..6491e48
> > --- /dev/null
> > +++ b/drivers/misc/ssi/ssi_driver_int.c
> > @@ -0,0 +1,232 @@
> > +/*
> > + * ssi_driver_int.c
> > + *
> > + * Implements SSI interrupt functionality.
> > + *
> > + * Copyright (C) 2007-2008 Nokia Corporation. All rights reserved.
> > + *
> > + * Contact: Carlos Chinea <[email protected]>
> > + *
> > + * This program is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU General Public License
> > + * version 2 as published by the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope that it will be useful, but
> > + * WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> > + * General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU General Public License
> > + * along with this program; if not, write to the Free Software
> > + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
> > + * 02110-1301 USA
> > + */
> > +#include "ssi_driver.h"
> > +
> > +static void reset_ch_read(struct ssi_channel *ch)
> > +{
> > + ch->read_data.addr = NULL;
> > + ch->read_data.size = 0;
> > + ch->read_data.lch = -1;
> > +}
> > +
> > +static void reset_ch_write(struct ssi_channel *ch)
> > +{
> > + ch->write_data.addr = NULL;
> > + ch->write_data.size = 0;
> > + ch->write_data.lch = -1;
> > +}
> > +
> > +int ssi_driver_write_interrupt(struct ssi_channel *ch, u32 *data)
> > +{
> > + struct ssi_port *p = ch->ssi_port;
> > + unsigned int port = p->port_number;
> > + unsigned int channel = ch->channel_number;
> > +
> > + clk_enable(p->ssi_controller->ssi_clk);
> > + ssi_outl_or(SSI_SST_DATAACCEPT(channel), p->ssi_controller->base,
> > + SSI_SYS_MPU_ENABLE_REG(port, p->n_irq));
> > +
> > +

one blank line is enough.

> > + return 0;
> > +}
> > +
> > +int ssi_driver_read_interrupt(struct ssi_channel *ch, u32 *data)
> > +{
> > + struct ssi_port *p = ch->ssi_port;
> > + unsigned int port = p->port_number;
> > + unsigned int channel = ch->channel_number;
> > +
> > + clk_enable(p->ssi_controller->ssi_clk);
> > +
> > + ssi_outl_or(SSI_SSR_DATAAVAILABLE(channel), p->ssi_controller->base,
> > + SSI_SYS_MPU_ENABLE_REG(port, p->n_irq));
> > +
> > + clk_disable(p->ssi_controller->ssi_clk);
> > +
> > + return 0;
> > +}
> > +
> > +void ssi_driver_cancel_write_interrupt(struct ssi_channel *ch)
> > +{
> > + struct ssi_port *p = ch->ssi_port;
> > + unsigned int port = p->port_number;
> > + unsigned int channel = ch->channel_number;
> > + void __iomem *base = p->ssi_controller->base;
> > + u32 enable;
> > +
> > + clk_enable(p->ssi_controller->ssi_clk);
> > +
> > + enable = ssi_inl(base, SSI_SYS_MPU_ENABLE_REG(port, p->n_irq));
> > + if (!(enable & SSI_SST_DATAACCEPT(channel))) {
> > + dev_dbg(&ch->dev->device, LOG_NAME "Write cancel on not "
> > + "enabled channel %d ENABLE REG 0x%08X", channel, enable);
> > + clk_disable(p->ssi_controller->ssi_clk);
> > + return;
> > + }
> > + ssi_outl_and(~SSI_SST_DATAACCEPT(channel), base,
> > + SSI_SYS_MPU_ENABLE_REG(port, p->n_irq));
> > + ssi_outl_and(~NOTFULL(channel), base, SSI_SST_BUFSTATE_REG(port));
> > + reset_ch_write(ch);
> > +
> > + clk_disable(p->ssi_controller->ssi_clk);
> > + clk_disable(p->ssi_controller->ssi_clk);
> > +

remove this extra line

> > +}
> > +
> > +void ssi_driver_cancel_read_interrupt(struct ssi_channel *ch)
> > +{
> > + struct ssi_port *p = ch->ssi_port;
> > + unsigned int port = p->port_number;
> > + unsigned int channel = ch->channel_number;
> > + void __iomem *base = p->ssi_controller->base;
> > +
> > + clk_enable(p->ssi_controller->ssi_clk);
> > +
> > + ssi_outl_and(~SSI_SSR_DATAAVAILABLE(channel), base,
> > + SSI_SYS_MPU_ENABLE_REG(port, p->n_irq));
> > + ssi_outl_and(~NOTEMPTY(channel), base, SSI_SSR_BUFSTATE_REG(port));
> > + reset_ch_read(ch);
> > +
> > + clk_disable(p->ssi_controller->ssi_clk);
> > +}
> > +
> > +static void do_channel_tx(struct ssi_channel *ch)
> > +{
> > + struct ssi_dev *ssi_ctrl = ch->ssi_port->ssi_controller;
> > + void __iomem *base = ssi_ctrl->base;
> > + unsigned int n_ch;
> > + unsigned int n_p;
> > + unsigned int irq;
> > +
> > + n_ch = ch->channel_number;
> > + n_p = ch->ssi_port->port_number;
> > + irq = ch->ssi_port->n_irq;
> > +
> > + spin_lock(&ssi_ctrl->lock);
> > +
> > + if (ch->write_data.addr == NULL) {
> > + ssi_outl_and(~SSI_SST_DATAACCEPT(n_ch), base,
> > + SSI_SYS_MPU_ENABLE_REG(n_p, irq));
> > + reset_ch_write(ch);
> > + spin_unlock(&ssi_ctrl->lock);
> > + clk_disable(ssi_ctrl->ssi_clk);
> > + (*ch->ops.write_done)(ch->dev);
> > + } else {
> > + ssi_outl(*(ch->write_data.addr), base,
> > + SSI_SST_BUFFER_CH_REG(n_p, n_ch));
> > + ch->write_data.addr = NULL;
> > + spin_unlock(&ssi_ctrl->lock);
> > + }
> > +}
> > +
> > +static void do_channel_rx(struct ssi_channel *ch)
> > +{
> > + struct ssi_dev *ssi_ctrl = ch->ssi_port->ssi_controller;
> > + void __iomem *base = ch->ssi_port->ssi_controller->base;
> > + unsigned int n_ch;
> > + unsigned int n_p;
> > + unsigned int irq;
> > +
> > + n_ch = ch->channel_number;
> > + n_p = ch->ssi_port->port_number;
> > + irq = ch->ssi_port->n_irq;
> > +
> > + spin_lock(&ssi_ctrl->lock);
> > +
> > + *(ch->read_data.addr) = ssi_inl(base, SSI_SSR_BUFFER_CH_REG(n_p, n_ch));
> > +
> > + ssi_outl_and(~SSI_SSR_DATAAVAILABLE(n_ch), base,
> > + SSI_SYS_MPU_ENABLE_REG(n_p, irq));
> > + reset_ch_read(ch);
> > +
> > + spin_unlock(&ssi_ctrl->lock);
> > +
> > + (*ch->ops.read_done)(ch->dev);
> > +}
> > +
> > +void do_ssi_tasklet(unsigned long ssi_port)
> > +{
> > + struct ssi_port *pport = (struct ssi_port *)ssi_port;
> > + struct ssi_dev *ssi_ctrl = pport->ssi_controller;
> > + void __iomem *base = ssi_ctrl->base;
> > + unsigned int port = pport->port_number;
> > + unsigned int channel = 0;
> > + unsigned int irq = pport->n_irq;
> > + u32 status_reg;
> > + u32 enable_reg;
> > + u32 ssr_err_reg;
> > + u32 channels_served;
> > +
> > + clk_enable(ssi_ctrl->ssi_clk);
> > +
> > + channels_served = 0;
> > + status_reg = ssi_inl(base, SSI_SYS_MPU_STATUS_REG(port, irq));
> > + enable_reg = ssi_inl(base, SSI_SYS_MPU_ENABLE_REG(port, irq));
> > +
> > + for (channel = 0; channel < pport->max_ch; channel++) {
> > + if ((status_reg & SSI_SST_DATAACCEPT(channel)) &&
> > + (enable_reg & SSI_SST_DATAACCEPT(channel))) {
> > + do_channel_tx(&pport->ssi_channel[channel]);
> > + channels_served |= SSI_SST_DATAACCEPT(channel);
> > + }
> > +
> > + if ((status_reg & SSI_SSR_DATAAVAILABLE(channel)) &&
> > + (enable_reg & SSI_SSR_DATAAVAILABLE(channel))) {
> > + do_channel_rx(&pport->ssi_channel[channel]);
> > + channels_served |= SSI_SSR_DATAAVAILABLE(channel);
> > + }
> > + }
> > +
> > + if ((status_reg & SSI_BREAKDETECTED) &&
> > + (enable_reg & SSI_BREAKDETECTED)) {
> > + dev_info(&ssi_ctrl->pdev->dev,
> > + "Hardware BREAK on port %d\n", port);
> > + ssi_outl(0, base, SSI_SSR_BREAK_REG(port));
> > + ssi_port_event_handler(pport, SSI_EVENT_BREAK_DETECTED, NULL);
> > + }
> > +
> > + if (status_reg & SSI_ERROROCCURED) {
> > + ssr_err_reg = ssi_inl(base, SSI_SSR_ERROR_REG(port));
> > + dev_err(&ssi_ctrl->pdev->dev, "SSI ERROR Port %d: 0x%02x\n",
> > + port, ssr_err_reg);
> > + ssi_outl(ssr_err_reg, base, SSI_SSR_ERRORACK_REG(port));
> > + ssi_port_event_handler(pport, SSI_EVENT_ERROR, NULL);
> > + }
> > +
> > + ssi_outl((channels_served | SSI_ERROROCCURED | SSI_BREAKDETECTED), base,
> > + SSI_SYS_MPU_STATUS_REG(port, irq));
> > +
> > + clk_disable(ssi_ctrl->ssi_clk);
> > + enable_irq(pport->irq);
> > +}

I might have more comments on this later. But I'll wait until you come
with the new version and these comments fixed to look at it again.

--
balbi

2008-10-09 16:47:44

by Felipe Balbi

[permalink] [raw]

Subject: Re: [RFC][PATCH 5/5] OMAP SSI API documentation

On Fri, Oct 03, 2008 at 02:52:30PM +0300, Carlos Chinea wrote:

there are issues in the documentation as well.

> Signed-off-by: Carlos Chinea <[email protected]>
> ---
> Documentation/arm/OMAP/ssi/board-ssi.c.example | 216 ++++++++++++++++++++++
> Documentation/arm/OMAP/ssi/ssi | 232 ++++++++++++++++++++++++
> 2 files changed, 448 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/arm/OMAP/ssi/board-ssi.c.example
> create mode 100644 Documentation/arm/OMAP/ssi/ssi
>
> diff --git a/Documentation/arm/OMAP/ssi/board-ssi.c.example b/Documentation/arm/OMAP/ssi/board-ssi.c.example
> new file mode 100644
> index 0000000..a346628
> --- /dev/null
> +++ b/Documentation/arm/OMAP/ssi/board-ssi.c.example
> @@ -0,0 +1,216 @@
> +/*
> + * board-ssi.c.example
> + *
> + * Copyright (C) 2007-2008 Nokia Corporation. All rights reserved.
> + *
> + * Contact: Carlos Chinea <[email protected]>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * version 2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
> + * 02110-1301 USA
> + */
> +
> +#ifdef CONFIG_OMAP_SSI

don't ifdef here. This file should only be built if SSI is selected.

> +
> +#include <linux/platform_device.h>
> +#include <linux/err.h>
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/ssi_driver_if.h>
> +#include <mach/ssi/ssi_sys_reg.h>
> +#include <mach/ssi/ssi_ssr_reg.h>
> +#include <mach/ssi/ssi_sst_reg.h>

you see how many includes you need to make it work ?

It should be #include <linux/ssi.h> and that's all. This driver can be
generic enough to build and work on non-omap platforms, can't it ?

> +
> +#include "clock.h"
> +
> +struct ssi_internal_clk {
> + struct clk clk;
> + struct clk **childs;
> + int n_childs;
> + struct platform_device *pdev;

why do you need to let the internal clock know so much about the user ?
I think struct device * should be enough here.

> +};
> +
> +static struct ssi_internal_clk ssi_clock;
> +
> +static void ssi_pdev_release(struct device *dev)
> +{
> +}
> +
> +static struct ssi_port_pd ssi_ports[] = {
> + [0] = {
> + .tx_mode = SSI_MODE_FRAME,
> + .tx_frame_size = SSI_FRAMESIZE_DEFAULT,
> + .divisor = SSI_DIVISOR_DEFAULT,
> + .tx_ch = SSI_CHANNELS_DEFAULT,
> + .arb_mode = SSI_ARBMODE_ROUNDROBIN,
> + .rx_mode = SSI_MODE_FRAME,
> + .rx_frame_size = SSI_FRAMESIZE_DEFAULT,
> + .rx_ch = SSI_CHANNELS_DEFAULT,
> + .timeout = SSI_TIMEOUT_DEFAULT,
> + .n_irq = 0,
> + },

tabify these.

> +};
> +
> +static struct ssi_platform_data ssi_p_d = {
> + .clk_name = "ssi_clk",
> + .num_ports = ARRAY_SIZE(ssi_ports),
> + .ports = ssi_ports,

tabify

> +};
> +
> +static struct resource ssi_resources[] = {
> + [0] = {
> + .start = SSI_IOMEM_BASE_ADDR,
> + .end = SSI_IOMEM_BASE_ADDR + SSI_IOMEM_SIZE,
> + .name = SSI_IOMEM_NAME,
> + .flags = IORESOURCE_MEM,
> + },

tabify and the closing bracket should be aligned with [0]

> + [1] = {
^ trailing whitespace

> + .start = SSI_P1_MPU_IRQ0,
> + .end = SSI_P1_MPU_IRQ0,
> + .name = SSI_P1_MPU_IRQ0_NAME,
> + .flags = IORESOURCE_IRQ,
> + },

tabify
tabify and the closing bracket should be aligned with [1]

> + [2] = {
^ trailing whitespace

> + .start = SSI_P1_MPU_IRQ1,
> + .end = SSI_P1_MPU_IRQ1,
> + .name = SSI_P1_MPU_IRQ1_NAME,
> + .flags = IORESOURCE_IRQ,
> + },

tabify
tabify and the closing bracket should be aligned with [2]

> + [3] = {
^ trailing whitespace

> + .start = SSI_P2_MPU_IRQ0,
> + .end = SSI_P2_MPU_IRQ0,
> + .name = SSI_P2_MPU_IRQ0_NAME,
> + .flags = IORESOURCE_IRQ,
> + },

tabify
tabify and the closing bracket should be aligned with [3]

> + [4] = {
^ trailing whitespace

> + .start = SSI_P2_MPU_IRQ1,
> + .end = SSI_P2_MPU_IRQ1,
> + .name = SSI_P2_MPU_IRQ1_NAME,
> + .flags = IORESOURCE_IRQ,
> + },

tabify
tabify and the closing bracket should be aligned with [4]

> + [5] = {
^ trailing whitespace

> + .start = SSI_GDD_MPU_IRQ,
> + .end = SSI_GDD_MPU_IRQ,
> + .name = SSI_GDD_MPU_IRQ_NAME,
> + .flags = IORESOURCE_IRQ,
> + },

tabify and the closing bracket should be aligned with [5]

> +};
> +
> +static struct platform_device ssi_pdev = {
> + .name = "omap_ssi",
> + .id = -1,
> + .num_resources = ARRAY_SIZE(ssi_resources),
> + .resource = ssi_resources,
> + .dev = {
^ trailing whitespace

> + .release = ssi_pdev_release,
> + .platform_data = &ssi_p_d,
> + },

this bracket should be aligned with .dev

> +};
> +
> +static void set_ssi_mode(struct platform_device *pdev, u32 mode)
> +{
> + void __iomem *base = (void __iomem *)pdev->resource[0].start;

this is wrong, looks like mode sould be passed down to the driver and
the driver would set_ssi_mode().

> + int port;
> + int num_ports = ((struct ssi_platform_data *)

the cast is unnecessary and you're abusing platform_data, I'd say.

> + (pdev->dev.platform_data))->num_ports;
> +
> + for (port = 0; port < num_ports; port++) {
> + outl(mode, OMAP2_IO_ADDRESS(base + SSI_SST_MODE_REG(port)));
> + outl(mode, OMAP2_IO_ADDRESS(base + SSI_SSR_MODE_REG(port)));
> + }
> +}
> +
> +static int ssi_clk_init(struct ssi_internal_clk *ssi_clk)
> +{
> + const char *clk_names[] = { "ssi_ick", "ssi_ssr_fck" };
> + int i;
> + int j;
> +
> + ssi_clk->n_childs = ARRAY_SIZE(clk_names);
> + ssi_clk->childs = kzalloc(ssi_clk->n_childs * sizeof(*ssi_clk->childs),
> + GFP_KERNEL);
> + if (!ssi_clk->childs)
> + return -ENOMEM;
> +
> + for (i = 0; i < ssi_clk->n_childs; i++) {
> + ssi_clk->childs[i] = clk_get(NULL, clk_names[i]);
> + if (IS_ERR(ssi_clk->childs[i])) {
> + pr_err("Unable to get SSI clock: %s", clk_names[i]);
> + for (j = i - 1; j >= 0; j--)
> + clk_put(ssi_clk->childs[j]);
> + return -ENODEV;
> + }
> + }

this looks like it should be done by the driver and not board-specific.

> +
> + return 0;
> +}
> +
> +static int ssi_clk_enable(struct clk *clk)
> +{
> + struct ssi_internal_clk *ssi_clk =
> + container_of(clk, struct ssi_internal_clk, clk);
> + int err = 0;
> + int i;
> + int j;
> +
> + for (i = 0; ((i < ssi_clk->n_childs) && (err >= 0)); i++)
> + err = omap2_clk_enable(ssi_clk->childs[i]);
> +
> + if (unlikely(err < 0)) {
> + pr_err("Error on SSI clk %d\n", i);
> + for (j = i - 1; j >= 0; j--)
> + omap2_clk_disable(ssi_clk->childs[j]);

if you get and error, return already, will avoid the else below.

> + } else {
> + if (ssi_clk->clk.usecount == 1)
> + set_ssi_mode(ssi_clk->pdev, SSI_MODE_FRAME);
> + }
> +
> + return err;
> +}
> +
> +static void ssi_clk_disable(struct clk *clk)
> +{
> + struct ssi_internal_clk *ssi_clk =
> + container_of(clk, struct ssi_internal_clk, clk);
> +
> + int i;
> +
> + if (ssi_clk->clk.usecount == 0)
> + set_ssi_mode(ssi_clk->pdev, SSI_MODE_SLEEP);
> +
> + for (i = 0; i < ssi_clk->n_childs; i++)
> + omap2_clk_disable(ssi_clk->childs[i]);
> +}
> +
> +static struct ssi_internal_clk ssi_clock = {
> + .clk = {
> + .name = "ssi_clk",
> + .id = -1,
> + .enable = ssi_clk_enable,
> + .disable = ssi_clk_disable,
> + },
> + .pdev = &ssi_pdev,
> +};

it doesn't look like you do anything useful with this ssi_internal_clk
structure. I'd say you can move the clk definition to <mach/clock.h> if
Tony, Paul and Kevin are ok with it.

> +
> +void __init ssi_init(void)
> +{
> + int err;
> +
> + ssi_clk_init(&ssi_clock);
> + clk_register(&ssi_clock.clk);
> +
> + err = platform_device_register(&ssi_pdev);
> + if (err < 0)
> + pr_err("Unable to register SSI platform device: %d\n", err);

if the clk definition can be moved to <mach/clock.h> then you can
simply:

return platform_device_register(&ssi_pdev);

> +}
> +#endif
> diff --git a/Documentation/arm/OMAP/ssi/ssi b/Documentation/arm/OMAP/ssi/ssi
> new file mode 100644
> index 0000000..990ae48
> --- /dev/null
> +++ b/Documentation/arm/OMAP/ssi/ssi

let's use an extension to this file: ssi.txt

> @@ -0,0 +1,232 @@
> +OMAP SSI API's How To
> +=====================
> +
> +The Synchronous Serial Interface (SSI) is a high speed communication interface
> +that is used for connecting OMAP to a cellular modem engine.
> +
> +The SSI interface supports full duplex communication over multiple channels and
> +is capable of reaching speeds up to 110 Mbit/s
> +
> +I OMAP SSI driver API overview
> +-----------------------------
> +
> +A) SSI Bus, SSI channels and protocol drivers overview.
^ trailing whitespace

> +
> +The OMAP SSI driver is intended to be used inside the kernel by protocol drivers.
> +
> +The OMAP SSI abstracts the concept of SSI channels by creating an SSI bus an

s/an/and (at the end)

> +attaching SSI channel devices to it.(see Figure 1)
^ add a space

> +
> +Protocol drivers will then claim one or more SSI channels, after registering with the OMAP SSI driver.
> +
> + +---------------------+ +----------------+
> + + SSI channel device + + SSI protocol +
> + + (omap_ssi.pX-cY) + <-------+ driver +
> + +---------------------+ +----------------+
> + | |
> +(/sys/bus/ssi/devices/omap_ssi.pX-cy) (/sys/bus/ssi/drivers/ssi_protocol)
> + | |
> ++---------------------------------------------------------------+
> ++ SSI bus +
> ++---------------------------------------------------------------+
> +
> + Figure 1.
> +
> +(NOTE: omap_ssi.pX-cY represents the SSI channel Y on port X from the omap_ssi
> +device)

you could go simpler and call it:

/sys/bus/ssi/devices/X-Y: (X == port, Y == channel);

> +
> +B) Data transfers
> +
> +The OMAP SSI driver exports an asynchronous interface for sending and receiving
> +data over the SSI channels. Protocol drivers will register a set of read and write
> +completion callbacks for each SSI channel they use.
> +
> +Protocol drivers call ssi_write/ssi_read functions to signal the OMAP SSI driver
> +that is willing to write/read data to/from a channel. Transfers are completed only
> +when the OMAP SSI driver calls the completion callback.
> +
> +An SSI channel can simultaneously have both a read and a write request
> +pending, however, requests cannot be queued.
> +
> +It is safe to call ssi_write/ssi_read functions inside the callbacks functions.
> +In fact, a protocol driver should normally re-issue the read request from within
> +the read callback, in order to not miss any incoming messages.
> +
> +C) Error handling
> +
> +SSI is a multi channel interface but the channels share the same physical wires.
> +Therefore, any transmission error potentially affects all the protocol drivers
> +that sit on top of the SSI driver. Whenever an error occurs, it is broadcasted to
> +all protocol drivers.
> +
> +Errors are signaled to the protocol drivers through the port_event callback.
> +Protocol drivers can avoid receiving those notifications by not setting the
> +SSI_EVENT_ERROR in the event_mask field.(see struct ssi_device_driver)
> +
> +Completion callbacks functions are only called when a transfer has succeed.
> +
> +II OMAP SSI API's
> +-----------------
> +
> +A) Include
> +
> +#include<linux/ssi_driver_if.h>
> +
> +B) int register_ssi_driver(struct ssi_device_driver *driver);
> +
> +Description: Register an SSI protocol driver
> +
> +Parameter: A protocol driver declaration (see struct ssi_device_driver)
> +
> +B) void unregister_ssi_driver(struct ssi_device_driver *driver);
> +
> +Description: Unregister an SSI protocol driver
> +
> +Parameter: A protocol driver declaration (see struct ssi_device_driver)
> +
> +C) int ssi_open(struct ssi_device *dev);
> +
> +Description: Open an SSI device channel
> +
> +Parameter: The SSI channel
> +
> +D) int ssi_write(struct ssi_device *dev, u32 *data, unsigned int count);
> +
> +Description: Send data through an SSI channel. The transfer is only completed
> +when the write_complete callback is called
> +
> +Parameters:
> + - dev: SSI channel
> + - data: pointer to the data to send
> + - count: number of 32-bit words to be sent
> +
> +E) void ssi_write_cancel(struct ssi_device *dev);
> +
> +Description: Cancel current pending write operation
> +
> +Parameters: SSI channel
> +
> +F) int ssi_read(struct ssi_device *dev, u32 *data, unsigned int w_count);
> +
> +Description: Receive data through an SSI channel. The transfer is only completed
> +when the read_complete callback is called
> +
> +Parameters:
> + - dev: SSI channel
> + - data: pointer where to store the data
> + - count: number of 32-bit words to be read
> +
> +
> +G) void ssi_read_cancel(struct ssi_device *dev);
> +
> +Description: Cancel current pending read operation
> +
> +Parameters: SSI channel
> +
> +H) int ssi_ioctl(struct ssi_device *dev, unsigned int command, void *arg);
> +
> +Description: Apply some control command to the port associated to the given
> +SSI channel
> +
> +Parameters:
> + - dev: SSI channel
> + - command: command to execute
> + - arg: parameter for the control command
> +
> +Commands:
> + - SSI_IOCTL_WAKE_UP:
> + Description: Set SSI wakeup line for the channel
> + Parameters: None
> + - SSI_IOCTL_WAKE_DOWN:
> + Description: Unset SSI wakeup line for the channel
> + Parameters: None
> + - SSI_IOCTL_SEND_BREAK:
> + Description: Send a HW BREAK frame in FRAME mode
> + Parameters: None
> + - SSI_IOCTL_WAKE:
> + Description: Get wakeup line status
> + Parameters: Pointer to a u32 variable to return result
> + (Result: 0 means wakeline DOWN, other result means wakeline UP)
> +
> +I)void ssi_close(struct ssi_device *dev);
> +
> +Description: Close an SSI channel
> +
> +Parameters: The SSI channel to close
> +
> +J) void ssi_dev_set_cb( struct ssi_device *dev,
> + void (*r_cb)(struct ssi_device *dev),
> + void (*w_cb)(struct ssi_device *dev));
> +
> +Description: Set the read and write callbacks for the SSI channel. This
> +function is usually called in the probe function of the SSI protocol driver to
> +set completion callbacks for the asynchronous read and write transfer
> +
> +Parameters:
> + - dev: SSI channel
> + - r_cb: Pointer to a callback function to signal that a read transfer is
> + completed
> + - w_cb: Pointer to a callback function to signal that a write transfer
> + is completed
> +
> +H) struct ssi_device_driver
> +
> +Description: Protocol drivers pass this struct to the register_ssi_driver function
> +in order to register with the OMAP SSI driver. Among other things it tells the
> +OMAP SSI driver which channels the protocol driver wants to allocate for its use
> +
> +Declaration:
> +struct ssi_device_driver {
> + unsigned long ctrl_mask;
> + unsigned long ch_mask[SSI_MAX_PORTS];
> + unsigned long event_mask;
> + void (*port_event) (int c_id, unsigned int port,
> + unsigned int event, void *arg);
> + int (*probe)(struct ssi_device *dev);
> + int (*remove)(struct ssi_device *dev);
> + int (*suspend)(struct ssi_device *dev,
> + pm_message_t mesg);
> + int (*resume)(struct ssi_device *dev);
> + struct device_driver driver;
> +};
> +
> +Fields description:
> + ctrl_mask: SSI block ids to use
> + ch_mask[SSI_MAX_PORTS]: SSI channels to use
> + event_mask: SSI events to be notified
> + port_event: Function callback for notifying SSI events
> + (i.e.: error transfer)
> + Parameters:
> + c_id: SSI Block id which generate the event
> + port: Port number which generate the event
> + event: Event code
> + probe: Probe function
> + Parameters: SSI channel
> + remove: Remove function
> + Parameters: SSI channel
> +
> +Example:
> +
> +static struct ssi_device_driver ssi_protocol_driver = {
> + .ctrl_mask = ANY_SSI_CONTROLLER,
> + .ch_mask[0] = CHANNEL(0) | CHANNEL(1),
> + .event_mask = SSI_EVENT_ERROR_MASK,
> + .port_event = port_event_callback,
> + .probe = ssi_proto_probe,
> + .remove = __devexit_p(ssi_proto_remove),
> + .driver = {
> + .name = "ssi_protocol",
> + },
> +};
> +
> +
> +III OMAP SSI platform_device
> +----------------------------
> +
> +You can find a example of how to define an SSI platform device in:
> +
> +Documentation/arm/OMAP/ssi/board-ssi.c.example
> +
> +=================================================
> +Contact: Carlos Chinea <[email protected]>
> +Copyright (C) 2008 Nokia Corporation.
> --
> 1.5.3.6
>
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--
balbi