iio:dac: Add support for the ad5449

This patch adds support for the AD5415, AD5426, AD5429, AD5432, AD5439, AD5443
and AD5449 single and dual channel DACs.

Signed-off-by: Lars-Peter Clausen <[e-mail]>
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/dac/Kconfig

···
 	  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

drivers/iio/dac/Makefile

···
 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

drivers/iio/dac/ad5449.c

···
+/*
+ * AD5415, AD5426, AD5429, AD5432, AD5439, AD5443, AD5449 Digital to Analog
+ * Converter driver.
+ *
+ * Copyright 2012 Analog Devices Inc.
+ *  Author: Lars-Peter Clausen <[e-mail]>
+ *
+ * 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 <[e-mail]>");
+MODULE_DESCRIPTION("Analog Devices AD5449 and similar DACs");
+MODULE_LICENSE("GPL v2");

include/linux/platform_data/ad5449.h

···
+/*
+ * AD5415, AD5426, AD5429, AD5432, AD5439, AD5443, AD5449 Digital to Analog
+ * Converter driver.
+ *
+ * Copyright 2012 Analog Devices Inc.
+ *  Author: Lars-Peter Clausen <[e-mail]>
+ *
+ * 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