Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752356AbaLFLgc (ORCPT ); Sat, 6 Dec 2014 06:36:32 -0500 Received: from mout.gmx.net ([212.227.15.15]:51840 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752077AbaLFLga (ORCPT ); Sat, 6 Dec 2014 06:36:30 -0500 Message-ID: <5482EA33.7020305@gmx.de> Date: Sat, 06 Dec 2014 12:36:19 +0100 From: Hartmut Knaack User-Agent: Mozilla/5.0 (X11; Linux i686; rv:33.0) Gecko/20100101 Firefox/33.0 SeaMonkey/2.30 MIME-Version: 1.0 To: Nikolaus Schulz , Jonathan Cameron , Lars-Peter Clausen , Peter Meerwald , Grant Likely , Rob Herring , Michael Welling , Philippe Reynes , linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org, devicetree@vger.kernel.org CC: Alban Bedel Subject: Re: [PATCH v2 2/2] iio: add driver for the TI DAC8554 References: <1416858614-32265-1-git-send-email-nikolaus.schulz@avionic-design.de> <1416858614-32265-2-git-send-email-nikolaus.schulz@avionic-design.de> In-Reply-To: <1416858614-32265-2-git-send-email-nikolaus.schulz@avionic-design.de> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Provags-ID: V03:K0:hvFZQNvhL60MxTbm/6urRQ8UmBuIfznmAZxGQHcz7kvvTcwaRjg BOBiXBWYzJ9VgfFrH4i766AXc/ReP22K7zUC6YXLQo/ooI92B/z1F8GgtrUkTLWfrVc/hEE KuEh8fK7/trcLBS8Vr/B1KI56xNAoDfLKdcZxxcnVLrD1PSKLXetxJuibDLe9JNIdPhQEB9 hz7YOjADVc8Pxl0mHR0rw== X-UI-Out-Filterresults: notjunk:1; Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Nikolaus Schulz schrieb am 24.11.2014 um 20:50: > The TI DAC8554 is a quad-channel Digital-to-Analog Converter with an SPI > interface. > > Changes in v2: > * Use DMA-safe buffer for SPI transfer > * Normalize powerdown_mode name "hi-z" to "three_state" as per > ABI/testing/sysfs-bus-iio > * Register device late in probe function > * Avoid powerdown broadcast update, which touches all DAC on the bus There are a few issues left, please see my comments inline. > > Signed-off-by: Nikolaus Schulz > --- > drivers/iio/dac/Kconfig | 10 ++ > drivers/iio/dac/Makefile | 1 + > drivers/iio/dac/ti-dac8554.c | 374 +++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 385 insertions(+) > create mode 100644 drivers/iio/dac/ti-dac8554.c > > diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig > index 2236ea2..1689260 100644 > --- a/drivers/iio/dac/Kconfig > +++ b/drivers/iio/dac/Kconfig > @@ -181,4 +181,14 @@ config MCP4922 > To compile this driver as a module, choose M here: the module > will be called mcp4922. > > +config TI_DAC8554 > + tristate "TI DAC8554 driver" > + depends on SPI > + depends on OF > + help > + Say yes here to build the driver for the TI DAC8554. > + > + To compile this driver as a module, choose M here: the module > + will be called ti-dac8554. > + > endmenu > diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile > index 52be7e1..b98d79a 100644 > --- a/drivers/iio/dac/Makefile > +++ b/drivers/iio/dac/Makefile > @@ -20,3 +20,4 @@ obj-$(CONFIG_MAX517) += max517.o > obj-$(CONFIG_MAX5821) += max5821.o > obj-$(CONFIG_MCP4725) += mcp4725.o > obj-$(CONFIG_MCP4922) += mcp4922.o > +obj-$(CONFIG_TI_DAC8554) += ti-dac8554.o > diff --git a/drivers/iio/dac/ti-dac8554.c b/drivers/iio/dac/ti-dac8554.c > new file mode 100644 > index 0000000..fca751f > --- /dev/null > +++ b/drivers/iio/dac/ti-dac8554.c > @@ -0,0 +1,374 @@ > +/* > + * TI DAC8554 Digital to Analog Converter SPI driver > + * > + * Copyright (C) 2014 Avionic Design GmbH > + * > + * Based on ad5446r_spi.c > + * Copyright (C) 2010,2011 Analog Devices Inc. > + * > + * 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. > + */ > + > +#include > +#include > +#include > +#include > +#include > + > +#define DAC8554_DRIVERNAME "ti-dac8554" > +#define DAC8554_DAC_CHANNELS 4 > + > +/* Load commands */ > +#define DAC8554_CMD_STORE_DAC_N 0x0 > +#define DAC8554_CMD_UPDATE_DAC_N 0x1 > +#define DAC8554_CMD_STORE_DAC_N_UPDATE_ALL 0x2 > +#define DAC8554_CMD_UPDATE_BROADCAST 0x3 > + > +#define DAC8554_BROADCAST_USE_SRDATA 0x2 Add a blank line here. > +/* Powerdown modes (ORed PD1|PD2 bits) */ It took my some time to figure out ORed. I think you could drop it and just mention (PD1 | PD2 bits). > +#define DAC8554_PWRDN_HIZ 0x0 > +#define DAC8554_PWRDN_1K 0x1 > +#define DAC8554_PWRDN_100K 0x2 > + > +#define DAC8554_PWRDN_TO_SR(mode) (BIT(16) | (mode) << 14) > + > +/** > + * struct dac8554_state - driver instance specific data > + * @spi: spi_device SPI device? > + * @reg: supply regulator > + * @addr: two-bit chip address > + * @vref_mv: reference voltage in millivolt > + * @val DAC/channel data DAC channel data? > + * @powerdown channel powerdown flag > + * @powerdown_mode channel powerdown mode > + * @xfer SPI transfer buffer Half of the comments are with colon, the other half are missing it. > + */ > +struct dac8554_state { > + struct spi_device *spi; > + struct regulator *reg; > + unsigned addr; > + unsigned vref_mv; > + u16 val[DAC8554_DAC_CHANNELS]; > + bool powerdown[DAC8554_DAC_CHANNELS]; > + u8 powerdown_mode[DAC8554_DAC_CHANNELS]; > + > + /* > + * DMA (thus cache coherency maintenance) requires the > + * transfer buffers to live in their own cache lines. > + */ > + u8 xfer[3] ____cacheline_aligned; > +}; > + > +static int dac8554_spi_write(struct dac8554_state *st, > + unsigned cmd, > + unsigned chan_addr, > + unsigned val) > +{ > + u32 data; > + > + /* > + * The input shift register is 24 bits wide. The 8 MSB are > + * control bits, followed by 16 data bits. > + * The first two bits A1 and A0 address a DAC8554 chip. > + * The next two are the command bits, LD1 and LD0. > + * After a don't-care-bit, the next two bits select the channel. > + * The final control bit PD0 is a flag signalling if the data > + * bits encode a powerdown mode. We merge PD0 with the adjacent > + * data bits. > + */ > + > + if (cmd > 3 || chan_addr > 3 || > + (val > 0xffff && (val & ~DAC8554_PWRDN_TO_SR(3)))) > + return -EINVAL; > + > + data = (st->addr << 22) | (cmd << 20) | (chan_addr << 17) | val; Could be more readable by using definition for the magic shifts, or macros. > + st->xfer[0] = data >> 16; > + st->xfer[1] = data >> 8; > + st->xfer[2] = data; > + > + return spi_write(st->spi, st->xfer, sizeof(st->xfer)); > +} > + > +static int dac8554_read_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int *val, > + int *val2, > + long m) Commonly, m is called mask (like you do in _write_raw). > +{ > + struct dac8554_state *st = iio_priv(indio_dev); > + > + switch (m) { > + case IIO_CHAN_INFO_RAW: > + *val = st->val[chan->address]; > + return IIO_VAL_INT; > + case IIO_CHAN_INFO_SCALE: > + *val = st->vref_mv; > + *val2 = 16; > + return IIO_VAL_FRACTIONAL_LOG2; > + } > + return -EINVAL; > +} > + > +static int dac8554_write_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int val, > + int val2, > + long mask) > +{ > + struct dac8554_state *st = iio_priv(indio_dev); > + int err; > + > + switch (mask) { > + case IIO_CHAN_INFO_RAW: > + if (val > 0xffff || val < 0) > + return -EINVAL; > + > + err = dac8554_spi_write(st, DAC8554_CMD_UPDATE_DAC_N, > + chan->address, val); > + if (err) > + return err; > + > + st->val[chan->address] = val; > + > + /* By hw design, DAC updates automatically trigger powerup. */ > + st->powerdown[chan->address] = false; > + > + return 0; > + > + default: > + return -EINVAL; > + } > +} > + > +static int dac8554_get_powerdown_mode(struct iio_dev *indio_dev, > + const struct iio_chan_spec *chan) > +{ > + struct dac8554_state *st = iio_priv(indio_dev); > + > + return st->powerdown_mode[chan->address]; > +} > + > +static int dac8554_set_powerdown_mode(struct iio_dev *indio_dev, > + const struct iio_chan_spec *chan, > + unsigned int mode) > +{ > + struct dac8554_state *st = iio_priv(indio_dev); > + > + st->powerdown_mode[chan->address] = mode; > + > + return 0; > +} > + > +static ssize_t dac8554_read_dac_powerdown(struct iio_dev *indio_dev, > + uintptr_t private, > + const struct iio_chan_spec *chan, > + char *buf) > +{ > + struct dac8554_state *st = iio_priv(indio_dev); > + > + return sprintf(buf, "%d\n", st->powerdown[chan->address]); > +} > + > +static ssize_t dac8554_write_dac_powerdown(struct iio_dev *indio_dev, > + uintptr_t private, > + const struct iio_chan_spec *chan, > + const char *buf, > + size_t len) > +{ > + bool powerdown; > + int ret; > + struct dac8554_state *st = iio_priv(indio_dev); > + u8 powerdown_mode; > + > + ret = strtobool(buf, &powerdown); > + if (ret) > + return ret; > + > + st->powerdown[chan->address] = powerdown; > + > + if (powerdown) { > + powerdown_mode = st->powerdown_mode[chan->address]; > + ret = dac8554_spi_write(st, > + DAC8554_CMD_UPDATE_DAC_N, > + chan->address, > + DAC8554_PWRDN_TO_SR(powerdown_mode)); The parameters sill fit on line even with proper indentation. > + } else { > + /* Load DAC with cached value. This triggers a powerup. */ > + ret = dac8554_spi_write(st, > + DAC8554_CMD_UPDATE_DAC_N, > + chan->address, > + st->val[chan->address]); Same here with indentation. > + } > + > + if (ret) > + return ret; > + > + return len; Just: return (ret) ? ret : len; > +} > + > +static int dac8554_powerdown(struct dac8554_state *st, > + u8 powerdown_mode) > +{ > + int chan, cmd, ret; > + > + for (chan = DAC8554_DAC_CHANNELS-1; chan >= 0; --chan) { Please mind spaces around operators. > + cmd = chan ? DAC8554_CMD_STORE_DAC_N > + : DAC8554_CMD_STORE_DAC_N_UPDATE_ALL; > + ret = dac8554_spi_write(st, cmd, chan, > + DAC8554_PWRDN_TO_SR(powerdown_mode)); > + if (ret) > + return ret; > + } > + > + memset(st->powerdown_mode, powerdown_mode, sizeof(st->powerdown_mode)); > + memset(st->powerdown, true, sizeof(st->powerdown)); > + > + return 0; > +} > + > +static const struct iio_info dac8554_info = { > + .write_raw = dac8554_write_raw, > + .read_raw = dac8554_read_raw, > + .driver_module = THIS_MODULE, > +}; > + > +static const char * const dac8554_powerdown_modes[] = { > + "three_state", > + "1kohm_to_gnd", > + "100kohm_to_gnd" > +}; > + > +static const struct iio_enum dac8854_powerdown_mode_enum = { > + .items = dac8554_powerdown_modes, > + .num_items = ARRAY_SIZE(dac8554_powerdown_modes), > + .get = dac8554_get_powerdown_mode, > + .set = dac8554_set_powerdown_mode, > +}; > + > +static const struct iio_chan_spec_ext_info dac8554_ext_info[] = { > + { > + .name = "powerdown", > + .read = dac8554_read_dac_powerdown, > + .write = dac8554_write_dac_powerdown, > + .shared = IIO_SEPARATE, > + }, > + IIO_ENUM("powerdown_mode", IIO_SEPARATE, > + &dac8854_powerdown_mode_enum), > + IIO_ENUM_AVAILABLE("powerdown_mode", &dac8854_powerdown_mode_enum), > + { }, > +}; > + > +#define DAC8554_CHANNEL(chan) { \ > + .type = IIO_VOLTAGE, \ > + .indexed = 1, \ > + .output = 1, \ > + .channel = (chan), \ > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ > + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ > + .address = (chan), \ > + .ext_info = dac8554_ext_info, \ > +} > +const struct iio_chan_spec dac8554_channels[] = { > + DAC8554_CHANNEL(0), > + DAC8554_CHANNEL(1), > + DAC8554_CHANNEL(2), > + DAC8554_CHANNEL(3), > +}; > +#undef DAC8554_CHANNEL > + > +static int dac8554_probe(struct spi_device *spi) > +{ > + struct dac8554_state *st; > + struct iio_dev *indio_dev; > + int ret, voltage_uv; > + u32 addr; > + > + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); > + if (!indio_dev) > + return -ENOMEM; > + > + indio_dev->dev.parent = &spi->dev; > + indio_dev->name = DAC8554_DRIVERNAME; > + indio_dev->info = &dac8554_info; > + indio_dev->modes = INDIO_DIRECT_MODE; > + indio_dev->channels = dac8554_channels; > + indio_dev->num_channels = ARRAY_SIZE(dac8554_channels); > + > + spi_set_drvdata(spi, indio_dev); > + > + st = iio_priv(indio_dev); > + > + if (!spi->dev.of_node) { > + dev_err(&spi->dev, "missing OF node"); > + return -ENODEV; > + } > + ret = of_property_read_u32(spi->dev.of_node, "address", &addr); > + if (ret || addr < 0 || addr > 2) { > + dev_err(&spi->dev, "no or invalid chip address"); > + return -ENODEV; > + } > + > + st->spi = spi; > + st->addr = addr; > + According to your DT bindings, the regulator from property "vref-supply" should be used. This is missing here. > + st->reg = devm_regulator_get(&spi->dev, "vref"); > + if (IS_ERR(st->reg)) > + return PTR_ERR(st->reg); > + > + ret = regulator_enable(st->reg); > + if (ret) > + return ret; > + > + voltage_uv = regulator_get_voltage(st->reg); > + if (voltage_uv < 0) > + goto error_disable_reg; Missing ret = voltage_uv before goto. Or just drop voltage_uv completely and use ret instead. > + st->vref_mv = voltage_uv / 1000; How hard do you want to depend on a voltage regulator? Doing regulator_get_voltage() could even be called dynamically in _read_raw(), making a real regulator optional. > + > + ret = dac8554_powerdown(st, DAC8554_PWRDN_100K); > + if (ret) > + goto error_disable_reg; > + > + ret = iio_device_register(indio_dev); > + if (ret) > + goto error_disable_reg; > + > + return 0; > + > +error_disable_reg: > + regulator_disable(st->reg); > + return ret; > +} > + > +static int dac8554_remove(struct spi_device *spi) > +{ > + struct iio_dev *indio_dev = spi_get_drvdata(spi); > + struct dac8554_state *st = iio_priv(indio_dev); > + > + iio_device_unregister(indio_dev); > + regulator_disable(st->reg); > + > + return 0; > +} > + > +static const struct of_device_id dac8554_of_match[] = { > + { .compatible = "ti,dac8554" }, > + { } > +}; > +MODULE_DEVICE_TABLE(of, dac8554_of_match); > + > +static struct spi_driver dac8554_driver = { > + .driver = { > + .name = DAC8554_DRIVERNAME, > + .owner = THIS_MODULE, > + .of_match_table = dac8554_of_match, > + }, > + .probe = dac8554_probe, > + .remove = dac8554_remove, > +}; > +module_spi_driver(dac8554_driver); > + > +MODULE_AUTHOR("Nikolaus Schulz "); > +MODULE_DESCRIPTION("Texas Instruments DAC8554 SPI driver"); > +MODULE_LICENSE("GPL v2"); > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/