Re: [PATCH 2/2] iio:dac: Add support for the ad5449

[Jonathan Cameron <jic23@kernel.org>]

On 10/16/2012 05:29 PM, Lars-Peter Clausen wrote:
> This patch adds support for the AD5415, AD5426, AD5429, AD5432, AD5439, AD5443
> and AD5449 single and dual channel DACs.
> 
Clean, short and generally sweet. Just how I like it.
> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Merged to togreg branch of iio.git.
> ---
>  drivers/iio/dac/Kconfig              |   10 +
>  drivers/iio/dac/Makefile             |    1 +
>  drivers/iio/dac/ad5449.c             |  375 ++++++++++++++++++++++++++++++++++
>  include/linux/platform_data/ad5449.h |   40 ++++
>  4 files changed, 426 insertions(+)
>  create mode 100644 drivers/iio/dac/ad5449.c
>  create mode 100644 include/linux/platform_data/ad5449.h
> 
> diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
> index b1c0ee5..f68756e 100644
> --- a/drivers/iio/dac/Kconfig
> +++ b/drivers/iio/dac/Kconfig
> @@ -67,6 +67,16 @@ config AD5446
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called ad5446.
>  
> +config AD5449
> +	tristate "Analog Device AD5449 and similar DACs driver"
> +	depends on SPI_MASTER
> +	help
> +	  Say yes here to build support for Analog Devices AD5415, AD5426, AD5429,
> +	  AD5432, AD5439, AD5443, AD5449 Digital to Analog Converters.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called ad5449.
> +
>  config AD5504
>  	tristate "Analog Devices AD5504/AD5501 DAC SPI driver"
>  	depends on SPI
> diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
> index c0d333b..5b528eb 100644
> --- a/drivers/iio/dac/Makefile
> +++ b/drivers/iio/dac/Makefile
> @@ -9,6 +9,7 @@ obj-$(CONFIG_AD5624R_SPI) += ad5624r_spi.o
>  obj-$(CONFIG_AD5064) += ad5064.o
>  obj-$(CONFIG_AD5504) += ad5504.o
>  obj-$(CONFIG_AD5446) += ad5446.o
> +obj-$(CONFIG_AD5449) += ad5449.o
>  obj-$(CONFIG_AD5755) += ad5755.o
>  obj-$(CONFIG_AD5764) += ad5764.o
>  obj-$(CONFIG_AD5791) += ad5791.o
> diff --git a/drivers/iio/dac/ad5449.c b/drivers/iio/dac/ad5449.c
> new file mode 100644
> index 0000000..5b43030
> --- /dev/null
> +++ b/drivers/iio/dac/ad5449.c
> @@ -0,0 +1,375 @@
> +/*
> + * AD5415, AD5426, AD5429, AD5432, AD5439, AD5443, AD5449 Digital to Analog
> + * Converter driver.
> + *
> + * Copyright 2012 Analog Devices Inc.
> + *  Author: Lars-Peter Clausen <lars@metafoo.de>
> + *
> + * Licensed under the GPL-2.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/spi/spi.h>
> +#include <linux/slab.h>
> +#include <linux/sysfs.h>
> +#include <linux/regulator/consumer.h>
> +#include <asm/unaligned.h>
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +
> +#include <linux/platform_data/ad5449.h>
> +
> +#define AD5449_MAX_CHANNELS		2
> +#define AD5449_MAX_VREFS		2
> +
> +#define AD5449_CMD_NOOP			0x0
> +#define AD5449_CMD_LOAD_AND_UPDATE(x)	(0x1 + (x) * 3)
> +#define AD5449_CMD_READ(x)		(0x2 + (x) * 3)
> +#define AD5449_CMD_LOAD(x)		(0x3 + (x) * 3)
> +#define AD5449_CMD_CTRL			13
> +
> +#define AD5449_CTRL_SDO_OFFSET		10
> +#define AD5449_CTRL_DAISY_CHAIN		BIT(9)
> +#define AD5449_CTRL_HCLR_TO_MIDSCALE	BIT(8)
> +#define AD5449_CTRL_SAMPLE_RISING	BIT(7)
> +
> +/**
> + * struct ad5449_chip_info - chip specific information
> + * @channels:		Channel specification
> + * @num_channels:	Number of channels
> + * @has_ctrl:		Chip has a control register
> + */
> +struct ad5449_chip_info {
> +	const struct iio_chan_spec *channels;
> +	unsigned int num_channels;
> +	bool has_ctrl;
> +};
> +
> +/**
> + * struct ad5449 - driver instance specific data
> + * @spi:		the SPI device for this driver instance
> + * @chip_info:		chip model specific constants, available modes etc
> + * @vref_reg:		vref supply regulators
> + * @has_sdo:		whether the SDO line is connected
> + * @dac_cache:		Cache for the DAC values
> + * @data:		spi transfer buffers
> + */
> +struct ad5449 {
> +	struct spi_device		*spi;
> +	const struct ad5449_chip_info	*chip_info;
> +	struct regulator_bulk_data	vref_reg[AD5449_MAX_VREFS];
> +
> +	bool has_sdo;
> +	uint16_t dac_cache[AD5449_MAX_CHANNELS];
> +
> +	/*
> +	 * DMA (thus cache coherency maintenance) requires the
> +	 * transfer buffers to live in their own cache lines.
> +	 */
> +	__be16 data[2] ____cacheline_aligned;
> +};
> +
> +enum ad5449_type {
> +	ID_AD5426,
> +	ID_AD5429,
> +	ID_AD5432,
> +	ID_AD5439,
> +	ID_AD5443,
> +	ID_AD5449,
> +};
> +
> +static int ad5449_write(struct iio_dev *indio_dev, unsigned int addr,
> +	unsigned int val)
> +{
> +	struct ad5449 *st = iio_priv(indio_dev);
> +	int ret;
> +
> +	mutex_lock(&indio_dev->mlock);
> +	st->data[0] = cpu_to_be16((addr << 12) | val);
> +	ret = spi_write(st->spi, st->data, 2);
> +	mutex_unlock(&indio_dev->mlock);
> +
> +	return ret;
> +}
> +
> +static int ad5449_read(struct iio_dev *indio_dev, unsigned int addr,
> +	unsigned int *val)
> +{
> +	struct ad5449 *st = iio_priv(indio_dev);
> +	int ret;
> +	struct spi_message msg;
> +	struct spi_transfer t[] = {
> +		{
> +			.tx_buf = &st->data[0],
> +			.len = 2,
> +			.cs_change = 1,
> +		}, {
> +			.tx_buf = &st->data[1],
> +			.rx_buf = &st->data[1],
> +			.len = 2,
> +		},
> +	};
> +
> +	spi_message_init(&msg);
> +	spi_message_add_tail(&t[0], &msg);
> +	spi_message_add_tail(&t[1], &msg);
> +
> +	mutex_lock(&indio_dev->mlock);
> +	st->data[0] = cpu_to_be16(addr << 12);
> +	st->data[1] = cpu_to_be16(AD5449_CMD_NOOP);
> +
> +	ret = spi_sync(st->spi, &msg);
> +	if (ret < 0)
> +		return ret;
> +
> +	*val = be16_to_cpu(st->data[1]);
> +	mutex_unlock(&indio_dev->mlock);
> +
> +	return 0;
> +}
> +
> +static int ad5449_read_raw(struct iio_dev *indio_dev,
> +	struct iio_chan_spec const *chan, int *val, int *val2, long info)
> +{
> +	struct ad5449 *st = iio_priv(indio_dev);
> +	struct regulator_bulk_data *reg;
> +	int scale_uv;
> +	int ret;
> +
> +	switch (info) {
> +	case IIO_CHAN_INFO_RAW:
> +		if (st->has_sdo) {
> +			ret = ad5449_read(indio_dev,
> +				AD5449_CMD_READ(chan->address), val);
> +			if (ret)
> +				return ret;
> +			*val &= 0xfff;
> +		} else {
> +			*val = st->dac_cache[chan->address];
> +		}
> +
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_SCALE:
> +		reg = &st->vref_reg[chan->channel];
> +		scale_uv = regulator_get_voltage(reg->consumer);
> +		if (scale_uv < 0)
> +			return scale_uv;
> +
> +		*val = scale_uv / 1000;
> +		*val2 = chan->scan_type.realbits;
> +
> +		return IIO_VAL_FRACTIONAL_LOG2;
> +	default:
> +		break;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int ad5449_write_raw(struct iio_dev *indio_dev,
> +	struct iio_chan_spec const *chan, int val, int val2, long info)
> +{
> +	struct ad5449 *st = iio_priv(indio_dev);
> +	int ret;
> +
> +	switch (info) {
> +	case IIO_CHAN_INFO_RAW:
> +		if (val < 0 || val >= (1 << chan->scan_type.realbits))
> +			return -EINVAL;
> +
> +		ret = ad5449_write(indio_dev,
> +			AD5449_CMD_LOAD_AND_UPDATE(chan->address),
> +			val << chan->scan_type.shift);
> +		if (ret == 0)
> +			st->dac_cache[chan->address] = val;
> +		break;
> +	default:
> +		ret = -EINVAL;
> +	}
> +
> +	return ret;
> +}
> +
> +static const struct iio_info ad5449_info = {
> +	.read_raw = ad5449_read_raw,
> +	.write_raw = ad5449_write_raw,
> +	.driver_module = THIS_MODULE,
> +};
> +
> +#define AD5449_CHANNEL(chan, bits) {				\
> +	.type = IIO_VOLTAGE,					\
> +	.indexed = 1,						\
> +	.output = 1,						\
> +	.channel = (chan),					\
> +	.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |		\
> +		IIO_CHAN_INFO_SCALE_SEPARATE_BIT,		\
> +	.address = (chan),					\
> +	.scan_type = IIO_ST('u', (bits), 16, 12 - (bits)),	\
> +}
> +
> +#define DECLARE_AD5449_CHANNELS(name, bits) \
> +const struct iio_chan_spec name[] = { \
> +	AD5449_CHANNEL(0, bits), \
> +	AD5449_CHANNEL(1, bits), \
> +}
> +
> +static DECLARE_AD5449_CHANNELS(ad5429_channels, 8);
> +static DECLARE_AD5449_CHANNELS(ad5439_channels, 10);
> +static DECLARE_AD5449_CHANNELS(ad5449_channels, 12);
> +
> +static const struct ad5449_chip_info ad5449_chip_info[] = {
> +	[ID_AD5426] = {
> +		.channels = ad5429_channels,
> +		.num_channels = 1,
> +		.has_ctrl = false,
> +	},
> +	[ID_AD5429] = {
> +		.channels = ad5429_channels,
> +		.num_channels = 2,
> +		.has_ctrl = true,
> +	},
> +	[ID_AD5432] = {
> +		.channels = ad5439_channels,
> +		.num_channels = 1,
> +		.has_ctrl = false,
> +	},
> +	[ID_AD5439] = {
> +		.channels = ad5439_channels,
> +		.num_channels = 2,
> +		.has_ctrl = true,
> +	},
> +	[ID_AD5443] = {
> +		.channels = ad5449_channels,
> +		.num_channels = 1,
> +		.has_ctrl = false,
> +	},
> +	[ID_AD5449] = {
> +		.channels = ad5449_channels,
> +		.num_channels = 2,
> +		.has_ctrl = true,
> +	},
> +};
> +
> +static const char *ad5449_vref_name(struct ad5449 *st, int n)
> +{
> +	if (st->chip_info->num_channels == 1)
> +		return "VREF";
> +
> +	if (n == 0)
> +		return "VREFA";
> +	else
> +		return "VREFB";
> +}
> +
> +static int __devinit ad5449_spi_probe(struct spi_device *spi)
> +{
> +	struct ad5449_platform_data *pdata = spi->dev.platform_data;
> +	const struct spi_device_id *id = spi_get_device_id(spi);
> +	struct iio_dev *indio_dev;
> +	struct ad5449 *st;
> +	unsigned int i;
> +	int ret;
> +
> +	indio_dev = iio_device_alloc(sizeof(*st));
> +	if (indio_dev == NULL)
> +		return -ENOMEM;
> +
> +	st = iio_priv(indio_dev);
> +	spi_set_drvdata(spi, indio_dev);
> +
> +	st->chip_info = &ad5449_chip_info[id->driver_data];
> +	st->spi = spi;
> +
> +	for (i = 0; i < st->chip_info->num_channels; ++i)
> +		st->vref_reg[i].supply = ad5449_vref_name(st, i);
> +
> +	ret = regulator_bulk_get(&spi->dev, st->chip_info->num_channels,
> +				st->vref_reg);
> +	if (ret)
> +		goto error_free;
> +
> +	ret = regulator_bulk_enable(st->chip_info->num_channels, st->vref_reg);
> +	if (ret)
> +		goto error_free_reg;
> +
> +	indio_dev->dev.parent = &spi->dev;
> +	indio_dev->name = id->name;
> +	indio_dev->info = &ad5449_info;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->channels = st->chip_info->channels;
> +	indio_dev->num_channels = st->chip_info->num_channels;
> +
> +	if (st->chip_info->has_ctrl) {
> +		unsigned int ctrl = 0x00;
> +		if (pdata) {
> +			if (pdata->hardware_clear_to_midscale)
> +				ctrl |= AD5449_CTRL_HCLR_TO_MIDSCALE;
> +			ctrl |= pdata->sdo_mode << AD5449_CTRL_SDO_OFFSET;
> +			st->has_sdo = pdata->sdo_mode != AD5449_SDO_DISABLED;
> +		} else {
> +			st->has_sdo = true;
> +		}
> +		ad5449_write(indio_dev, AD5449_CMD_CTRL, ctrl);
> +	}
> +
> +	ret = iio_device_register(indio_dev);
> +	if (ret)
> +		goto error_disable_reg;
> +
> +	return 0;
> +
> +error_disable_reg:
> +	regulator_bulk_disable(st->chip_info->num_channels, st->vref_reg);
> +error_free_reg:
> +	regulator_bulk_free(st->chip_info->num_channels, st->vref_reg);
> +error_free:
> +	iio_device_free(indio_dev);
> +
> +	return ret;
> +}
> +
> +static int __devexit ad5449_spi_remove(struct spi_device *spi)
> +{
> +	struct iio_dev *indio_dev = spi_get_drvdata(spi);
> +	struct ad5449 *st = iio_priv(indio_dev);
> +
> +	iio_device_unregister(indio_dev);
> +
> +	regulator_bulk_disable(st->chip_info->num_channels, st->vref_reg);
> +	regulator_bulk_free(st->chip_info->num_channels, st->vref_reg);
> +
> +	iio_device_free(indio_dev);
> +
> +	return 0;
> +}
> +
> +static const struct spi_device_id ad5449_spi_ids[] = {
> +	{ "ad5415", ID_AD5449 },
> +	{ "ad5426", ID_AD5426 },
> +	{ "ad5429", ID_AD5429 },
> +	{ "ad5432", ID_AD5432 },
> +	{ "ad5439", ID_AD5439 },
> +	{ "ad5443", ID_AD5443 },
> +	{ "ad5449", ID_AD5449 },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(spi, ad5449_spi_ids);
> +
> +static struct spi_driver ad5449_spi_driver = {
> +	.driver = {
> +		.name = "ad5449",
> +		.owner = THIS_MODULE,
> +	},
> +	.probe = ad5449_spi_probe,
> +	.remove = __devexit_p(ad5449_spi_remove),
> +	.id_table = ad5449_spi_ids,
> +};
> +module_spi_driver(ad5449_spi_driver);
> +
> +MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
> +MODULE_DESCRIPTION("Analog Devices AD5449 and similar DACs");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/platform_data/ad5449.h b/include/linux/platform_data/ad5449.h
> new file mode 100644
> index 0000000..bd712bd
> --- /dev/null
> +++ b/include/linux/platform_data/ad5449.h
> @@ -0,0 +1,40 @@
> +/*
> + * AD5415, AD5426, AD5429, AD5432, AD5439, AD5443, AD5449 Digital to Analog
> + * Converter driver.
> + *
> + * Copyright 2012 Analog Devices Inc.
> + *  Author: Lars-Peter Clausen <lars@metafoo.de>
> + *
> + * Licensed under the GPL-2.
> + */
> +
> +#ifndef __LINUX_PLATFORM_DATA_AD5449_H__
> +#define __LINUX_PLATFORM_DATA_AD5449_H__
> +
> +/**
> + * enum ad5449_sdo_mode - AD5449 SDO pin configuration
> + * @AD5449_SDO_DRIVE_FULL: Drive the SDO pin with full strength.
> + * @AD5449_SDO_DRIVE_WEAK: Drive the SDO pin with not full strength.
> + * @AD5449_SDO_OPEN_DRAIN: Operate the SDO pin in open-drain mode.
> + * @AD5449_SDO_DISABLED: Disable the SDO pin, in this mode it is not possible to
> + *			read back from the device.
> + */
> +enum ad5449_sdo_mode {
> +	AD5449_SDO_DRIVE_FULL = 0x0,
> +	AD5449_SDO_DRIVE_WEAK = 0x1,
> +	AD5449_SDO_OPEN_DRAIN = 0x2,
> +	AD5449_SDO_DISABLED = 0x3,
> +};
> +
> +/**
> + * struct ad5449_platform_data - Platform data for the ad5449 DAC driver
> + * @sdo_mode: SDO pin mode
> + * @hardware_clear_to_midscale: Whether asserting the hardware CLR pin sets the
> + *			outputs to midscale (true) or to zero scale(false).
> + */
> +struct ad5449_platform_data {
> +	enum ad5449_sdo_mode sdo_mode;
> +	bool hardware_clear_to_midscale;
> +};
> +
> +#endif
>