Re: [PATCH v4 1/2] iio:dac:ti-dac7311 Add driver for Texas Instrument DAC7311

[Jonathan Cameron <jic23@jic23.retrosnub.co.uk>]

Hi Charles-Antoine

A quick initial process comment. Please remember to detail changes
from previous versions below the ---.  Some of us reviewers have the memory
of a goldfish and hence have no idea what we commented on the previous
time ;)

Anyhow, I found v3 and it was just the CONFIG_OF stuff.

On Sun, 28 Oct 2018 17:24:01 +0100
Charles-Antoine Couret <charles-antoine.couret@essensium.com> wrote:

> It is a driver for Texas Instruments 8/10/12-bit 1-channel
> compatible with DAC6311 and DAC5311 chips.
> 
> Datasheet of this chip:
> http://www.ti.com/lit/ds/symlink/dac7311.pdf
Applied to the togreg branch of iio.git and pushed out as testing for
the autobuilders to play with it.

Thanks,

Jonathan

> 
> Signed-off-by: Charles-Antoine Couret <charles-antoine.couret@essensium.com>
> ---
>  drivers/iio/dac/Kconfig      |   9 +
>  drivers/iio/dac/Makefile     |   1 +
>  drivers/iio/dac/ti-dac7311.c | 338 +++++++++++++++++++++++++++++++++++
>  3 files changed, 348 insertions(+)
>  create mode 100644 drivers/iio/dac/ti-dac7311.c
> 
> diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
> index 80beb64e9e0c..ac205c8f5de0 100644
> --- a/drivers/iio/dac/Kconfig
> +++ b/drivers/iio/dac/Kconfig
> @@ -356,6 +356,15 @@ config TI_DAC5571
>  
>  	  If compiled as a module, it will be called ti-dac5571.
>  
> +config TI_DAC7311
> +	tristate "Texas Instruments 8/10/12-bit 1-channel DAC driver"
> +	depends on SPI
> +	help
> +	  Driver for the Texas Instruments
> +	  DAC7311, DAC6311, DAC5311.
> +
> +	  If compiled as a module, it will be called ti-dac7311.
> +
>  config VF610_DAC
>  	tristate "Vybrid vf610 DAC driver"
>  	depends on OF
> diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
> index a1b37cf99441..4b02021cc30f 100644
> --- a/drivers/iio/dac/Makefile
> +++ b/drivers/iio/dac/Makefile
> @@ -39,4 +39,5 @@ obj-$(CONFIG_STM32_DAC_CORE) += stm32-dac-core.o
>  obj-$(CONFIG_STM32_DAC) += stm32-dac.o
>  obj-$(CONFIG_TI_DAC082S085) += ti-dac082s085.o
>  obj-$(CONFIG_TI_DAC5571) += ti-dac5571.o
> +obj-$(CONFIG_TI_DAC7311) += ti-dac7311.o
>  obj-$(CONFIG_VF610_DAC) += vf610_dac.o
> diff --git a/drivers/iio/dac/ti-dac7311.c b/drivers/iio/dac/ti-dac7311.c
> new file mode 100644
> index 000000000000..6f5df1a30a1c
> --- /dev/null
> +++ b/drivers/iio/dac/ti-dac7311.c
> @@ -0,0 +1,338 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* ti-dac7311.c - Texas Instruments 8/10/12-bit 1-channel DAC driver
> + *
> + * Copyright (C) 2018 CMC NV
> + *
> + * http://www.ti.com/lit/ds/symlink/dac7311.pdf
> + */
> +
> +#include <linux/iio/iio.h>
> +#include <linux/module.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/spi/spi.h>
> +
> +enum {
> +	ID_DAC5311 = 0,
> +	ID_DAC6311,
> +	ID_DAC7311,
> +};
> +
> +enum {
> +	POWER_1KOHM_TO_GND = 0,
> +	POWER_100KOHM_TO_GND,
> +	POWER_TRI_STATE,
> +};
> +
> +struct ti_dac_spec {
> +	u8 resolution;
> +};
> +
> +static const struct ti_dac_spec ti_dac_spec[] = {
> +	[ID_DAC5311] = { .resolution = 8 },
> +	[ID_DAC6311] = { .resolution = 10 },
> +	[ID_DAC7311] = { .resolution = 12 },
> +};
> +
> +/**
> + * struct ti_dac_chip - TI DAC chip
> + * @lock: protects write sequences
> + * @vref: regulator generating Vref
> + * @spi: SPI device to send data to the device
> + * @val: cached value
> + * @powerdown: whether the chip is powered down
> + * @powerdown_mode: selected by the user
> + * @resolution: resolution of the chip
> + * @buf: buffer for transfer data
> + */
> +struct ti_dac_chip {
> +	struct mutex lock;
> +	struct regulator *vref;
> +	struct spi_device *spi;
> +	u16 val;
> +	bool powerdown;
> +	u8 powerdown_mode;
> +	u8 resolution;
> +	u8 buf[2] ____cacheline_aligned;
> +};
> +
> +static u8 ti_dac_get_power(struct ti_dac_chip *ti_dac, bool powerdown)
> +{
> +	if (powerdown)
> +		return ti_dac->powerdown_mode + 1;
> +
> +	return 0;
> +}
> +
> +static int ti_dac_cmd(struct ti_dac_chip *ti_dac, u8 power, u16 val)
> +{
> +	u8 shift = 14 - ti_dac->resolution;
> +
> +	ti_dac->buf[0] = (val << shift) & 0xFF;
> +	ti_dac->buf[1] = (power << 6) | (val >> (8 - shift));
> +	return spi_write(ti_dac->spi, ti_dac->buf, 2);
> +}
> +
> +static const char * const ti_dac_powerdown_modes[] = {
> +	"1kohm_to_gnd",
> +	"100kohm_to_gnd",
> +	"three_state",
> +};
> +
> +static int ti_dac_get_powerdown_mode(struct iio_dev *indio_dev,
> +				     const struct iio_chan_spec *chan)
> +{
> +	struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
> +
> +	return ti_dac->powerdown_mode;
> +}
> +
> +static int ti_dac_set_powerdown_mode(struct iio_dev *indio_dev,
> +				     const struct iio_chan_spec *chan,
> +				     unsigned int mode)
> +{
> +	struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
> +
> +	ti_dac->powerdown_mode = mode;
> +	return 0;
> +}
> +
> +static const struct iio_enum ti_dac_powerdown_mode = {
> +	.items = ti_dac_powerdown_modes,
> +	.num_items = ARRAY_SIZE(ti_dac_powerdown_modes),
> +	.get = ti_dac_get_powerdown_mode,
> +	.set = ti_dac_set_powerdown_mode,
> +};
> +
> +static ssize_t ti_dac_read_powerdown(struct iio_dev *indio_dev,
> +				     uintptr_t private,
> +				     const struct iio_chan_spec *chan,
> +				     char *buf)
> +{
> +	struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
> +
> +	return sprintf(buf, "%d\n", ti_dac->powerdown);
> +}
> +
> +static ssize_t ti_dac_write_powerdown(struct iio_dev *indio_dev,
> +				      uintptr_t private,
> +				      const struct iio_chan_spec *chan,
> +				      const char *buf, size_t len)
> +{
> +	struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
> +	bool powerdown;
> +	u8 power;
> +	int ret;
> +
> +	ret = strtobool(buf, &powerdown);
> +	if (ret)
> +		return ret;
> +
> +	power = ti_dac_get_power(ti_dac, powerdown);
> +
> +	mutex_lock(&ti_dac->lock);
> +	ret = ti_dac_cmd(ti_dac, power, 0);
> +	if (!ret)
> +		ti_dac->powerdown = powerdown;
> +	mutex_unlock(&ti_dac->lock);
> +
> +	return ret ? ret : len;
> +}
> +
> +static const struct iio_chan_spec_ext_info ti_dac_ext_info[] = {
> +	{
> +		.name	   = "powerdown",
> +		.read	   = ti_dac_read_powerdown,
> +		.write	   = ti_dac_write_powerdown,
> +		.shared	   = IIO_SHARED_BY_TYPE,
> +	},
> +	IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE, &ti_dac_powerdown_mode),
> +	IIO_ENUM_AVAILABLE("powerdown_mode", &ti_dac_powerdown_mode),
> +	{ },
> +};
> +
> +#define TI_DAC_CHANNEL(chan) {					\
> +	.type = IIO_VOLTAGE,					\
> +	.channel = (chan),					\
> +	.output = true,						\
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
> +	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
> +	.ext_info = ti_dac_ext_info,				\
> +}
> +
> +static const struct iio_chan_spec ti_dac_channels[] = {
> +	TI_DAC_CHANNEL(0),
> +};
> +
> +static int ti_dac_read_raw(struct iio_dev *indio_dev,
> +			   struct iio_chan_spec const *chan,
> +			   int *val, int *val2, long mask)
> +{
> +	struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
> +	int ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		*val = ti_dac->val;
> +		return IIO_VAL_INT;
> +
> +	case IIO_CHAN_INFO_SCALE:
> +		ret = regulator_get_voltage(ti_dac->vref);
> +		if (ret < 0)
> +			return ret;
> +
> +		*val = ret / 1000;
> +		*val2 = ti_dac->resolution;
> +		return IIO_VAL_FRACTIONAL_LOG2;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int ti_dac_write_raw(struct iio_dev *indio_dev,
> +			    struct iio_chan_spec const *chan,
> +			    int val, int val2, long mask)
> +{
> +	struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
> +	u8 power = ti_dac_get_power(ti_dac, ti_dac->powerdown);
> +	int ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		if (ti_dac->val == val)
> +			return 0;
> +
> +		if (val >= (1 << ti_dac->resolution) || val < 0)
> +			return -EINVAL;
> +
> +		if (ti_dac->powerdown)
> +			return -EBUSY;
> +
> +		mutex_lock(&ti_dac->lock);
> +		ret = ti_dac_cmd(ti_dac, power, val);
> +		if (!ret)
> +			ti_dac->val = val;
> +		mutex_unlock(&ti_dac->lock);
> +		break;
> +
> +	default:
> +		ret = -EINVAL;
> +	}
> +
> +	return ret;
> +}
> +
> +static int ti_dac_write_raw_get_fmt(struct iio_dev *indio_dev,
> +				    struct iio_chan_spec const *chan, long mask)
> +{
> +	return IIO_VAL_INT;
> +}
> +
> +static const struct iio_info ti_dac_info = {
> +	.read_raw	   = ti_dac_read_raw,
> +	.write_raw	   = ti_dac_write_raw,
> +	.write_raw_get_fmt = ti_dac_write_raw_get_fmt,
> +};
> +
> +static int ti_dac_probe(struct spi_device *spi)
> +{
> +	struct device *dev = &spi->dev;
> +	const struct ti_dac_spec *spec;
> +	struct ti_dac_chip *ti_dac;
> +	struct iio_dev *indio_dev;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(dev, sizeof(*ti_dac));
> +	if (!indio_dev) {
> +		dev_err(dev, "can not allocate iio device\n");
> +		return -ENOMEM;
> +	}
> +
> +	spi->mode = SPI_MODE_1;
> +	spi->bits_per_word = 16;
> +	spi_setup(spi);
> +
> +	indio_dev->dev.parent = dev;
> +	indio_dev->dev.of_node = spi->dev.of_node;
> +	indio_dev->info = &ti_dac_info;
> +	indio_dev->name = spi_get_device_id(spi)->name;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->channels = ti_dac_channels;
> +	spi_set_drvdata(spi, indio_dev);
> +
> +	ti_dac = iio_priv(indio_dev);
> +	ti_dac->powerdown = false;
> +	ti_dac->spi = spi;
> +
> +	spec = &ti_dac_spec[spi_get_device_id(spi)->driver_data];
> +	indio_dev->num_channels = 1;
> +	ti_dac->resolution = spec->resolution;
> +
> +	ti_dac->vref = devm_regulator_get(dev, "vref");
> +	if (IS_ERR(ti_dac->vref)) {
> +		dev_err(dev, "error to get regulator\n");
> +		return PTR_ERR(ti_dac->vref);
> +	}
> +
> +	ret = regulator_enable(ti_dac->vref);
> +	if (ret < 0) {
> +		dev_err(dev, "can not enable regulator\n");
> +		return ret;
> +	}
> +
> +	mutex_init(&ti_dac->lock);
> +
> +	ret = iio_device_register(indio_dev);
> +	if (ret) {
> +		dev_err(dev, "fail to register iio device: %d\n", ret);
> +		goto err;
> +	}
> +
> +	return 0;
> +
> +err:
> +	mutex_destroy(&ti_dac->lock);
> +	regulator_disable(ti_dac->vref);
> +	return ret;
> +}
> +
> +static int ti_dac_remove(struct spi_device *spi)
> +{
> +	struct iio_dev *indio_dev = spi_get_drvdata(spi);
> +	struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
> +
> +	iio_device_unregister(indio_dev);
> +	mutex_destroy(&ti_dac->lock);
> +	regulator_disable(ti_dac->vref);
> +	return 0;
> +}
> +
> +static const struct of_device_id ti_dac_of_id[] = {
> +	{ .compatible = "ti,dac5311" },
> +	{ .compatible = "ti,dac6311" },
> +	{ .compatible = "ti,dac7311" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, ti_dac_of_id);
> +
> +static const struct spi_device_id ti_dac_spi_id[] = {
> +	{ "dac5311", ID_DAC5311  },
> +	{ "dac6311", ID_DAC6311 },
> +	{ "dac7311", ID_DAC7311 },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(spi, ti_dac_spi_id);
> +
> +static struct spi_driver ti_dac_driver = {
> +	.driver = {
> +		.name		= "ti-dac7311",
> +		.of_match_table	= ti_dac_of_id,
> +	},
> +	.probe	  = ti_dac_probe,
> +	.remove   = ti_dac_remove,
> +	.id_table = ti_dac_spi_id,
> +};
> +module_spi_driver(ti_dac_driver);
> +
> +MODULE_AUTHOR("Charles-Antoine Couret <charles-antoine.couret@essensium.com>");
> +MODULE_DESCRIPTION("Texas Instruments 8/10/12-bit 1-channel DAC driver");
> +MODULE_LICENSE("GPL v2");