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Date: Fri, 16 Jul 2010 11:24:21 +0800
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Subject: Re: [PATCH v2] i2c/nuc900: add i2c driver support for nuc900
From: Wan ZongShun <mcuos.com@gmail.com>
To: LKML <linux-kernel@vger.kernel.org>, linux-i2c@vger.kernel.org,
        Ben Dooks <ben-linux@fluff.org>,
        "Jean Delvare (PC drivers, core)" <khali@linux-fr.org>
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How about this patch?
Which tree can merge it?

2010/6/28 Wan ZongShun <mcuos.com@gmail.com>:
> Hi Ben,
>
> How about this patch? Can it be applied?
>
> Thanks!
>
>> This patch is to add i2c driver support for nuc900.
>>
>> v1->v2 changes:
>> Address the comments of Ben Dooks
>>
>> (1) Document registers Macro definitions.
>> (1) Modify some documents apply to kernel doc style.
>> (2) clk_get shouldn't need the second argument, so remove it.
>> (3) clk_get_rate() should be used.
>> (5) Add irq IRQF_SHARED flag.
>> (6) change i2s_nuc900_irq_nextbyte() declaration type from 'int' to 'void'
>>    it does not need return value.
>> (7) To enable irq easier.
>>
>> Signed-off-by: Wan ZongShun <mcuos.com@gmail.com>
>> Reviewed-by: Marek Vasut <marek.vasut@gmail.com>
>> Reviewed-by: Baruch Siach <baruch@tkos.co.il>
>> ---
>>  arch/arm/mach-w90x900/include/mach/i2c.h |    9 +
>>  drivers/i2c/busses/Kconfig               |    7 +
>>  drivers/i2c/busses/Makefile              |    1 +
>>  drivers/i2c/busses/i2c-nuc900.c          |  709 ++++++++++++++++++++++++++++++
>>  4 files changed, 726 insertions(+), 0 deletions(-)
>>  create mode 100644 arch/arm/mach-w90x900/include/mach/i2c.h
>>  create mode 100644 drivers/i2c/busses/i2c-nuc900.c
>>
>> diff --git a/arch/arm/mach-w90x900/include/mach/i2c.h b/arch/arm/mach-w90x900/include/mach/i2c.h
>> new file mode 100644
>> index 0000000..9ffb12d
>> --- /dev/null
>> +++ b/arch/arm/mach-w90x900/include/mach/i2c.h
>> @@ -0,0 +1,9 @@
>> +#ifndef __ASM_ARCH_NUC900_I2C_H
>> +#define __ASM_ARCH_NUC900_I2C_H
>> +
>> +struct nuc900_platform_i2c {
>> +       int             bus_num;
>> +       unsigned long   bus_freq;
>> +};
>> +
>> +#endif /* __ASM_ARCH_NUC900_I2C_H */
>> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
>> index bceafbf..ee284d2 100644
>> --- a/drivers/i2c/busses/Kconfig
>> +++ b/drivers/i2c/busses/Kconfig
>> @@ -448,6 +448,13 @@ config I2C_NOMADIK
>>          If you say yes to this option, support will be included for the
>>          I2C interface from ST-Ericsson's Nomadik and Ux500 architectures.
>>
>> +config I2C_NUC900
>> +       tristate "NUC900 I2C Driver"
>> +       depends on ARCH_W90X900
>> +       help
>> +         Say Y here to include support for I2C controller in the
>> +         Winbond/Nuvoton NUC900 based System-on-Chip devices.
>> +
>>  config I2C_OCORES
>>        tristate "OpenCores I2C Controller"
>>        depends on EXPERIMENTAL
>> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
>> index 936880b..c3ef492 100644
>> --- a/drivers/i2c/busses/Makefile
>> +++ b/drivers/i2c/busses/Makefile
>> @@ -43,6 +43,7 @@ obj-$(CONFIG_I2C_IXP2000)     += i2c-ixp2000.o
>>  obj-$(CONFIG_I2C_MPC)          += i2c-mpc.o
>>  obj-$(CONFIG_I2C_MV64XXX)      += i2c-mv64xxx.o
>>  obj-$(CONFIG_I2C_NOMADIK)      += i2c-nomadik.o
>> +obj-$(CONFIG_I2C_NUC900)       += i2c-nuc900.o
>>  obj-$(CONFIG_I2C_OCORES)       += i2c-ocores.o
>>  obj-$(CONFIG_I2C_OMAP)         += i2c-omap.o
>>  obj-$(CONFIG_I2C_PASEMI)       += i2c-pasemi.o
>> diff --git a/drivers/i2c/busses/i2c-nuc900.c b/drivers/i2c/busses/i2c-nuc900.c
>> new file mode 100644
>> index 0000000..7a13b28
>> --- /dev/null
>> +++ b/drivers/i2c/busses/i2c-nuc900.c
>> @@ -0,0 +1,709 @@
>> +/*
>> + * linux/drivers/i2c/busses/i2c-nuc900.c
>> + *
>> + * Copyright (c) 2010 Nuvoton technology corporation.
>> + *
>> + * This driver based on S3C2410 I2C driver of Ben Dooks <ben@simtec.co.uk>.
>> + * Written by Wan ZongShun <mcuos.com@gmail.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation;version 2 of the License.
>> + *
>> + */
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +
>> +#include <linux/i2c.h>
>> +#include <linux/i2c-id.h>
>> +#include <linux/init.h>
>> +#include <linux/time.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/delay.h>
>> +#include <linux/errno.h>
>> +#include <linux/err.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/clk.h>
>> +#include <linux/cpufreq.h>
>> +#include <linux/slab.h>
>> +#include <linux/io.h>
>> +
>> +#include <mach/mfp.h>
>> +#include <mach/i2c.h>
>> +
>> +/* nuc900 i2c registers offset */
>> +
>> +#define CSR            0x00
>> +#define DIVIDER                0x04
>> +#define CMDR           0x08
>> +#define SWR            0x0C
>> +#define RXR            0x10
>> +#define TXR            0x14
>> +
>> +/* nuc900 i2c CSR register bits */
>> +
>> +#define IRQEN          0x003
>> +#define I2CBUSY                0x400
>> +#define I2CSTART       0x018
>> +#define IRQFLAG                0x004
>> +#define ARBIT_LOST     0x200
>> +#define SLAVE_ACK      0x800
>> +
>> +/* nuc900 i2c CMDR register bits */
>> +
>> +#define I2C_CMD_START  0x10
>> +#define I2C_CMD_STOP   0x08
>> +#define I2C_CMD_READ   0x04
>> +#define I2C_CMD_WRITE  0x02
>> +#define I2C_CMD_NACK   0x01
>> +
>> +/* i2c controller state */
>> +
>> +enum nuc900_i2c_state {
>> +       STATE_IDLE,
>> +       STATE_START,
>> +       STATE_READ,
>> +       STATE_WRITE,
>> +       STATE_STOP
>> +};
>> +
>> +/* i2c controller private data */
>> +
>> +struct nuc900_i2c {
>> +       spinlock_t              lock;
>> +       wait_queue_head_t       wait;
>> +
>> +       struct i2c_msg          *msg;
>> +       unsigned int            msg_num;
>> +       unsigned int            msg_idx;
>> +       unsigned int            msg_ptr;
>> +       unsigned int            irq;
>> +
>> +       enum nuc900_i2c_state   state;
>> +
>> +       void __iomem            *regs;
>> +       struct clk              *clk;
>> +       struct device           *dev;
>> +       struct resource         *ioarea;
>> +       struct i2c_adapter      adap;
>> +};
>> +
>> +/* nuc900_i2c_master_complete
>> + *
>> + * complete the message and wake up the caller, using the given return code,
>> + * or zero to mean ok.
>> +*/
>> +
>> +static inline void nuc900_i2c_master_complete(struct nuc900_i2c *i2c, int ret)
>> +{
>> +       dev_dbg(i2c->dev, "master_complete %d\n", ret);
>> +
>> +       i2c->msg_ptr = 0;
>> +       i2c->msg = NULL;
>> +       i2c->msg_idx++;
>> +       i2c->msg_num = 0;
>> +       if (ret)
>> +               i2c->msg_idx = ret;
>> +
>> +       wake_up(&i2c->wait);
>> +}
>> +
>> +/* irq enable/disable functions */
>> +
>> +static inline void nuc900_i2c_disable_irq(struct nuc900_i2c *i2c)
>> +{
>> +       unsigned long tmp;
>> +
>> +       tmp = readl(i2c->regs + CSR);
>> +       writel(tmp & ~IRQEN, i2c->regs + CSR);
>> +}
>> +
>> +static inline void nuc900_i2c_enable_irq(struct nuc900_i2c *i2c)
>> +{
>> +       unsigned long tmp;
>> +
>> +       tmp = readl(i2c->regs + CSR);
>> +       writel(tmp | IRQEN, i2c->regs + CSR);
>> +}
>> +
>> +
>> +/* nuc900_i2c_message_start
>> + *
>> + * put the start of a message onto the bus
>> +*/
>> +
>> +static void nuc900_i2c_message_start(struct nuc900_i2c *i2c,
>> +                                     struct i2c_msg *msg)
>> +{
>> +       unsigned int addr = (msg->addr & 0x7f) << 1;
>> +
>> +       if (msg->flags & I2C_M_RD)
>> +               addr |= 0x1;
>> +       writel(addr & 0xff, i2c->regs + TXR);
>> +       writel(I2C_CMD_START | I2C_CMD_WRITE, i2c->regs + CMDR);
>> +}
>> +
>> +static inline void nuc900_i2c_stop(struct nuc900_i2c *i2c, int ret)
>> +{
>> +
>> +       dev_dbg(i2c->dev, "STOP\n");
>> +
>> +       /* stop the transfer */
>> +       i2c->state = STATE_STOP;
>> +       writel(I2C_CMD_STOP, i2c->regs + CMDR);
>> +
>> +       nuc900_i2c_master_complete(i2c, ret);
>> +       nuc900_i2c_disable_irq(i2c);
>> +}
>> +
>> +/* helper functions to determine the current state in the set of
>> + * messages we are sending
>> +*/
>> +
>> +/* is_lastmsg()
>> + *
>> + * returns TRUE if the current message is the last in the set
>> +*/
>> +
>> +static inline int is_lastmsg(struct nuc900_i2c *i2c)
>> +{
>> +       return i2c->msg_idx >= (i2c->msg_num - 1);
>> +}
>> +
>> +/* is_msglast
>> + *
>> + * returns TRUE if we this is the last byte in the current message
>> +*/
>> +
>> +static inline int is_msglast(struct nuc900_i2c *i2c)
>> +{
>> +       return i2c->msg_ptr == i2c->msg->len-1;
>> +}
>> +
>> +/* is_msgend
>> + *
>> + * returns TRUE if we reached the end of the current message
>> +*/
>> +
>> +static inline int is_msgend(struct nuc900_i2c *i2c)
>> +{
>> +       return i2c->msg_ptr >= i2c->msg->len;
>> +}
>> +
>> +/* i2c_nuc900_irq_nextbyte
>> + *
>> + * process an interrupt and work out what to do
>> + */
>> +
>> +static void i2c_nuc900_irq_nextbyte(struct nuc900_i2c *i2c,
>> +                                                       unsigned long iicstat)
>> +{
>> +       unsigned char byte;
>> +
>> +       switch (i2c->state) {
>> +
>> +       case STATE_IDLE:
>> +               dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __func__);
>> +               break;
>> +
>> +       case STATE_STOP:
>> +               dev_err(i2c->dev, "%s: called in STATE_STOP\n", __func__);
>> +               nuc900_i2c_disable_irq(i2c);
>> +               break;
>> +
>> +       case STATE_START:
>> +               /* last thing we did was send a start condition on the
>> +                * bus, or started a new i2c message
>> +                */
>> +
>> +               if (iicstat & SLAVE_ACK &&
>> +                   !(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
>> +                       /* ack was not received... */
>> +
>> +                       dev_dbg(i2c->dev, "ack was not received\n");
>> +                       nuc900_i2c_stop(i2c, -ENXIO);
>> +                       break;
>> +               }
>> +
>> +               if (i2c->msg->flags & I2C_M_RD)
>> +                       i2c->state = STATE_READ;
>> +               else
>> +                       i2c->state = STATE_WRITE;
>> +
>> +               /* terminate the transfer if there is nothing to do
>> +                * as this is used by the i2c probe to find devices.
>> +               */
>> +
>> +               if (is_lastmsg(i2c) && i2c->msg->len == 0) {
>> +                       nuc900_i2c_stop(i2c, 0);
>> +                       break;
>> +               }
>> +
>> +               if (i2c->state == STATE_READ)
>> +                       goto prepare_read;
>> +
>> +               /* fall through to the write state, as we will need to
>> +                * send a byte as well
>> +               */
>> +
>> +       case STATE_WRITE:
>> +               /* we are writing data to the device... check for the
>> +                * end of the message, and if so, work out what to do
>> +                */
>> +
>> +               if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
>> +                       if (iicstat & SLAVE_ACK) {
>> +                               dev_dbg(i2c->dev, "WRITE: No Ack\n");
>> +
>> +                               nuc900_i2c_stop(i2c, -ECONNREFUSED);
>> +                               break;
>> +                       }
>> +               }
>> +
>> +retry_write:
>> +
>> +               if (!is_msgend(i2c)) {
>> +                       byte = i2c->msg->buf[i2c->msg_ptr++];
>> +                       writeb(byte, i2c->regs + TXR);
>> +                       writel(I2C_CMD_WRITE, i2c->regs + CMDR);
>> +
>> +               } else if (!is_lastmsg(i2c)) {
>> +                       /* we need to go to the next i2c message */
>> +
>> +                       dev_dbg(i2c->dev, "WRITE: Next Message\n");
>> +
>> +                       i2c->msg_ptr = 0;
>> +                       i2c->msg_idx++;
>> +                       i2c->msg++;
>> +
>> +                       /* check to see if we need to do another message */
>> +                       if (i2c->msg->flags & I2C_M_NOSTART) {
>> +
>> +                               if (i2c->msg->flags & I2C_M_RD) {
>> +                                       /* cannot do this, the controller
>> +                                        * forces us to send a new START
>> +                                        * when we change direction
>> +                                       */
>> +
>> +                                       nuc900_i2c_stop(i2c, -EINVAL);
>> +                               }
>> +
>> +                               goto retry_write;
>> +                       } else {
>> +                               /* send the new start */
>> +                               nuc900_i2c_message_start(i2c, i2c->msg);
>> +                               i2c->state = STATE_START;
>> +                       }
>> +
>> +               } else {
>> +                       /* send stop */
>> +
>> +                       nuc900_i2c_stop(i2c, 0);
>> +               }
>> +               break;
>> +
>> +       case STATE_READ:
>> +               /* we have a byte of data in the data register, do
>> +                * something with it, and then work out wether we are
>> +                * going to do any more read/write
>> +                */
>> +
>> +               byte = readb(i2c->regs + RXR);
>> +               i2c->msg->buf[i2c->msg_ptr++] = byte;
>> +
>> +prepare_read:
>> +               if (is_msglast(i2c)) {
>> +                       /* last byte of buffer */
>> +
>> +                       if (is_lastmsg(i2c))
>> +                               writel(I2C_CMD_READ | I2C_CMD_NACK,
>> +                                                       i2c->regs + CMDR);
>> +
>> +               } else if (is_msgend(i2c)) {
>> +                       /* ok, we've read the entire buffer, see if there
>> +                        * is anything else we need to do
>> +                       */
>> +
>> +                       if (is_lastmsg(i2c)) {
>> +                               /* last message, send stop and complete */
>> +                               dev_dbg(i2c->dev, "READ: Send Stop\n");
>> +
>> +                               nuc900_i2c_stop(i2c, 0);
>> +                       } else {
>> +                               /* go to the next transfer */
>> +                               dev_dbg(i2c->dev, "READ: Next Transfer\n");
>> +
>> +                               i2c->msg_ptr = 0;
>> +                               i2c->msg_idx++;
>> +                               i2c->msg++;
>> +
>> +                               writel(I2C_CMD_READ, i2c->regs + CMDR);
>> +                       }
>> +
>> +               } else {
>> +                       writel(I2C_CMD_READ, i2c->regs + CMDR);
>> +               }
>> +
>> +               break;
>> +       }
>> +}
>> +
>> +/* nuc900_i2c_irq
>> + *
>> + * top level IRQ servicing routine
>> +*/
>> +
>> +static irqreturn_t nuc900_i2c_irq(int irqno, void *dev_id)
>> +{
>> +       struct nuc900_i2c *i2c = dev_id;
>> +       unsigned long status;
>> +
>> +       status = readl(i2c->regs + CSR);
>> +       writel(status | IRQFLAG, i2c->regs + CSR);
>> +
>> +       if (status & ARBIT_LOST) {
>> +               /* deal with arbitration loss */
>> +               dev_err(i2c->dev, "deal with arbitration loss\n");
>> +               goto out;
>> +       }
>> +
>> +       if (i2c->state == STATE_IDLE) {
>> +               dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n");
>> +               goto out;
>> +       }
>> +
>> +       /* pretty much this leaves us with the fact that we've
>> +        * transmitted or received whatever byte we last sent
>> +       */
>> +
>> +       i2c_nuc900_irq_nextbyte(i2c, status);
>> +
>> + out:
>> +       return IRQ_HANDLED;
>> +}
>> +
>> +
>> +/* nuc900_i2c_set_master
>> + *
>> + * get the i2c bus for a master transaction
>> +*/
>> +
>> +static int nuc900_i2c_set_master(struct nuc900_i2c *i2c)
>> +{
>> +       int timeout = 400;
>> +
>> +       while (timeout-- > 0) {
>> +               if (((readl(i2c->regs + SWR) & I2CSTART) == I2CSTART) &&
>> +                               ((readl(i2c->regs + CSR) & I2CBUSY) == 0)) {
>> +                       return 0;
>> +               }
>> +
>> +               msleep(1);
>> +       }
>> +
>> +       return -ETIMEDOUT;
>> +}
>> +
>> +/* nuc900_i2c_doxfer
>> + *
>> + * this starts an i2c transfer
>> +*/
>> +
>> +static int nuc900_i2c_doxfer(struct nuc900_i2c *i2c,
>> +                             struct i2c_msg *msgs, int num)
>> +{
>> +       unsigned long iicstat, timeout;
>> +       int spins = 20;
>> +       int ret;
>> +
>> +       ret = nuc900_i2c_set_master(i2c);
>> +       if (ret != 0) {
>> +               dev_err(i2c->dev, "cannot get bus (error %d)\n", ret);
>> +               ret = -EAGAIN;
>> +               goto out;
>> +       }
>> +
>> +       spin_lock_irq(&i2c->lock);
>> +
>> +       i2c->msg     = msgs;
>> +       i2c->msg_num = num;
>> +       i2c->msg_ptr = 0;
>> +       i2c->msg_idx = 0;
>> +       i2c->state   = STATE_START;
>> +
>> +       nuc900_i2c_message_start(i2c, msgs);
>> +       spin_unlock_irq(&i2c->lock);
>> +
>> +       timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
>> +
>> +       ret = i2c->msg_idx;
>> +
>> +       /* having these next two as dev_err() makes life very
>> +        * noisy when doing an i2cdetect
>> +       */
>> +
>> +       if (timeout == 0)
>> +               dev_dbg(i2c->dev, "timeout\n");
>> +       else if (ret != num)
>> +               dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
>> +
>> +       /* ensure the stop has been through the bus */
>> +
>> +       dev_dbg(i2c->dev, "waiting for bus idle\n");
>> +
>> +       /* first, try busy waiting briefly */
>> +       do {
>> +               iicstat = readl(i2c->regs + CSR);
>> +       } while ((iicstat & I2CBUSY) && --spins);
>> +
>> +       /* if that timed out sleep */
>> +       if (!spins) {
>> +               msleep(1);
>> +               iicstat = readl(i2c->regs + CSR);
>> +       }
>> +
>> +       if (iicstat & I2CBUSY)
>> +               dev_warn(i2c->dev, "timeout waiting for bus idle\n");
>> +
>> + out:
>> +       return ret;
>> +}
>> +
>> +/* nuc900_i2c_xfer
>> + *
>> + * first port of call from the i2c bus code when an message needs
>> + * transferring across the i2c bus.
>> +*/
>> +
>> +static int nuc900_i2c_xfer(struct i2c_adapter *adap,
>> +                       struct i2c_msg *msgs, int num)
>> +{
>> +       struct nuc900_i2c *i2c = (struct nuc900_i2c *)adap->algo_data;
>> +       int retry;
>> +       int ret;
>> +
>> +       nuc900_i2c_enable_irq(i2c);
>> +
>> +       for (retry = 0; retry < adap->retries; retry++) {
>> +
>> +               ret = nuc900_i2c_doxfer(i2c, msgs, num);
>> +
>> +               if (ret != -EAGAIN)
>> +                       return ret;
>> +
>> +               dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
>> +
>> +               udelay(100);
>> +       }
>> +
>> +       return -EREMOTEIO;
>> +}
>> +
>> +/* declare our i2c functionality */
>> +static u32 nuc900_i2c_func(struct i2c_adapter *adap)
>> +{
>> +       return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
>> +}
>> +
>> +/* i2c bus registration info */
>> +
>> +static const struct i2c_algorithm nuc900_i2c_algorithm = {
>> +       .master_xfer            = nuc900_i2c_xfer,
>> +       .functionality          = nuc900_i2c_func,
>> +};
>> +
>> +/* nuc900_i2c_probe
>> + *
>> + * called by the bus driver when a suitable device is found
>> +*/
>> +
>> +static int __devinit nuc900_i2c_probe(struct platform_device *pdev)
>> +{
>> +       struct nuc900_i2c *i2c;
>> +       struct nuc900_platform_i2c *pdata;
>> +       struct resource *res;
>> +       int ret;
>> +
>> +       pdata = pdev->dev.platform_data;
>> +       if (!pdata) {
>> +               dev_err(&pdev->dev, "no platform data\n");
>> +               return -EINVAL;
>> +       }
>> +
>> +       i2c = kzalloc(sizeof(struct nuc900_i2c), GFP_KERNEL);
>> +       if (!i2c) {
>> +               dev_err(&pdev->dev, "no memory for state\n");
>> +               return -ENOMEM;
>> +       }
>> +
>> +       strlcpy(i2c->adap.name, "nuc900-i2c0", sizeof(i2c->adap.name));
>> +       i2c->adap.owner   = THIS_MODULE;
>> +       i2c->adap.algo    = &nuc900_i2c_algorithm;
>> +       i2c->adap.retries = 2;
>> +       i2c->adap.class   = I2C_CLASS_HWMON | I2C_CLASS_SPD;
>> +
>> +       spin_lock_init(&i2c->lock);
>> +       init_waitqueue_head(&i2c->wait);
>> +
>> +       /* find the clock and enable it */
>> +
>> +       i2c->dev = &pdev->dev;
>> +       i2c->clk = clk_get(&pdev->dev, NULL);
>> +       if (IS_ERR(i2c->clk)) {
>> +               dev_err(&pdev->dev, "cannot get clock\n");
>> +               ret = -ENOENT;
>> +               goto err_noclk;
>> +       }
>> +
>> +       dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk);
>> +
>> +       clk_enable(i2c->clk);
>> +
>> +       /* map the registers */
>> +
>> +       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +       if (res == NULL) {
>> +               dev_err(&pdev->dev, "cannot find IO resource\n");
>> +               ret = -ENOENT;
>> +               goto err_clk;
>> +       }
>> +
>> +       i2c->ioarea = request_mem_region(res->start, resource_size(res),
>> +                                        pdev->name);
>> +
>> +       if (i2c->ioarea == NULL) {
>> +               dev_err(&pdev->dev, "cannot request IO\n");
>> +               ret = -ENXIO;
>> +               goto err_clk;
>> +       }
>> +
>> +       i2c->regs = ioremap(res->start, resource_size(res));
>> +
>> +       if (i2c->regs == NULL) {
>> +               dev_err(&pdev->dev, "cannot map IO\n");
>> +               ret = -ENXIO;
>> +               goto err_ioarea;
>> +       }
>> +
>> +       dev_dbg(&pdev->dev, "registers %p (%p, %p)\n",
>> +               i2c->regs, i2c->ioarea, res);
>> +
>> +       /* setup info block for the i2c core */
>> +
>> +       i2c->adap.algo_data = i2c;
>> +       i2c->adap.dev.parent = &pdev->dev;
>> +
>> +       mfp_set_groupg(&pdev->dev);
>> +
>> +       clk_get_rate(i2c->clk);
>> +
>> +       ret = (i2c->clk.apbfreq)/(pdata->bus_freq * 5) - 1;
>> +       writel(ret & 0xffff, i2c->regs + DIVIDER);
>> +
>> +       /* find the IRQ for this unit (note, this relies on the init call to
>> +        * ensure no current IRQs pending
>> +        */
>> +
>> +       i2c->irq = ret = platform_get_irq(pdev, 0);
>> +       if (ret <= 0) {
>> +               dev_err(&pdev->dev, "cannot find IRQ\n");
>> +               goto err_iomap;
>> +       }
>> +
>> +       ret = request_irq(i2c->irq, nuc900_i2c_irq, IRQF_DISABLED | IRQF_SHARED,
>> +                         dev_name(&pdev->dev), i2c);
>> +
>> +       if (ret != 0) {
>> +               dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq);
>> +               goto err_iomap;
>> +       }
>> +
>> +       /* Note, previous versions of the driver used i2c_add_adapter()
>> +        * to add the bus at any number. We now pass the bus number via
>> +        * the platform data, so if unset it will now default to always
>> +        * being bus 0.
>> +        */
>> +
>> +       i2c->adap.nr = pdata->bus_num;
>> +
>> +       ret = i2c_add_numbered_adapter(&i2c->adap);
>> +       if (ret < 0) {
>> +               dev_err(&pdev->dev, "failed to add bus to i2c core\n");
>> +               goto err_irq;
>> +       }
>> +
>> +       platform_set_drvdata(pdev, i2c);
>> +
>> +       dev_info(&pdev->dev, "%s: NUC900 I2C adapter\n",
>> +                                               dev_name(&i2c->adap.dev));
>> +       return 0;
>> +
>> + err_irq:
>> +       free_irq(i2c->irq, i2c);
>> +
>> + err_iomap:
>> +       iounmap(i2c->regs);
>> +
>> + err_ioarea:
>> +       release_resource(i2c->ioarea);
>> +       kfree(i2c->ioarea);
>> +
>> + err_clk:
>> +       clk_disable(i2c->clk);
>> +       clk_put(i2c->clk);
>> +
>> + err_noclk:
>> +       kfree(i2c);
>> +       return ret;
>> +}
>> +
>> +/* nuc900_i2c_remove
>> + *
>> + * called when device is removed from the bus
>> +*/
>> +
>> +static int __devexit nuc900_i2c_remove(struct platform_device *pdev)
>> +{
>> +       struct nuc900_i2c *i2c = platform_get_drvdata(pdev);
>> +
>> +       i2c_del_adapter(&i2c->adap);
>> +       free_irq(i2c->irq, i2c);
>> +
>> +       clk_disable(i2c->clk);
>> +       clk_put(i2c->clk);
>> +
>> +       iounmap(i2c->regs);
>> +
>> +       release_resource(i2c->ioarea);
>> +       kfree(i2c->ioarea);
>> +       kfree(i2c);
>> +
>> +       return 0;
>> +}
>> +
>> +static struct platform_driver nuc900_i2c_driver = {
>> +       .probe          = nuc900_i2c_probe,
>> +       .remove         = __devexit_p(nuc900_i2c_remove),
>> +       .driver         = {
>> +               .owner  = THIS_MODULE,
>> +               .name   = "nuc900-i2c0",
>> +       },
>> +};
>> +
>> +static int __init i2c_adap_nuc900_init(void)
>> +{
>> +       return platform_driver_register(&nuc900_i2c_driver);
>> +}
>> +
>> +static void __exit i2c_adap_nuc900_exit(void)
>> +{
>> +       platform_driver_unregister(&nuc900_i2c_driver);
>> +}
>> +subsys_initcall(i2c_adap_nuc900_init);
>> +module_exit(i2c_adap_nuc900_exit);
>> +
>> +MODULE_DESCRIPTION("NUC900 I2C Bus driver");
>> +MODULE_AUTHOR("Wan ZongShun, <mcuos.com@gmail.com>");
>> +MODULE_LICENSE("GPL");
>> +MODULE_ALIAS("platform:nuc900-i2c0");
>> --
>> 1.6.3.3
>>
>
>
>
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