staging:iio:dac: Add AD5360 driver

This patch adds support for the Analog Devices AD5360, AD5361, AD5362, AD5363,
AD5370, AD5371, AD5372, AD5373 multi-channel digital-to-analog converters.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 593 insertions, 0 deletions

diff --git a/drivers/staging/iio/dac/Kconfig b/drivers/staging/iio/dac/Kconfig
index 72281f8..fac8549 100644
--- a/drivers/staging/iio/dac/Kconfig
+++ b/drivers/staging/iio/dac/Kconfig
@@ -13,6 +13,17 @@ config AD5064
 	  To compile this driver as a module, choose M here: the
 	  module will be called ad5064.
 
+config AD5360
+	tristate "Analog Devices Analog Devices AD5360/61/62/63/70/71/73 DAC driver"
+	depends on SPI
+	help
+	  Say yes here to build support for Analog Devices AD5360, AD5361,
+	  AD5362, AD5363, AD5370, AD5371, AD5373 multi-channel
+	  Digital to Analog Converters (DAC).
+
+	  To compile this driver as module choose M here: the module will be called
+	  ad5360.
+
 config AD5624R_SPI
 	tristate "Analog Devices AD5624/44/64R DAC spi driver"
 	depends on SPI
diff --git a/drivers/staging/iio/dac/Makefile b/drivers/staging/iio/dac/Makefile
index ea49750..07b6f5e 100644
--- a/drivers/staging/iio/dac/Makefile
+++ b/drivers/staging/iio/dac/Makefile
@@ -2,6 +2,7 @@
 # Makefile for industrial I/O DAC drivers
 #
 
+obj-$(CONFIG_AD5360) += ad5360.o
 obj-$(CONFIG_AD5624R_SPI) += ad5624r_spi.o
 obj-$(CONFIG_AD5064) += ad5064.o
 obj-$(CONFIG_AD5504) += ad5504.o
diff --git a/drivers/staging/iio/dac/ad5360.c b/drivers/staging/iio/dac/ad5360.c
new file mode 100644
index 0000000..72d0f3f
--- /dev/null
+++ b/drivers/staging/iio/dac/ad5360.c
@@ -0,0 +1,581 @@
+/*
+ * Analog devices AD5360, AD5361, AD5362, AD5363, AD5370, AD5371, AD5373
+ * multi-channel Digital to Analog Converters driver
+ *
+ * Copyright 2011 Analog Devices Inc.
+ *
+ * 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 "../iio.h"
+#include "../sysfs.h"
+#include "dac.h"
+
+#define AD5360_CMD(x)				((x) << 22)
+#define AD5360_ADDR(x)				((x) << 16)
+
+#define AD5360_READBACK_TYPE(x)			((x) << 13)
+#define AD5360_READBACK_ADDR(x)			((x) << 7)
+
+#define AD5360_CHAN_ADDR(chan)			((chan) + 0x8)
+
+#define AD5360_CMD_WRITE_DATA			0x3
+#define AD5360_CMD_WRITE_OFFSET			0x2
+#define AD5360_CMD_WRITE_GAIN			0x1
+#define AD5360_CMD_SPECIAL_FUNCTION		0x0
+
+/* Special function register addresses */
+#define AD5360_REG_SF_NOP			0x0
+#define AD5360_REG_SF_CTRL			0x1
+#define AD5360_REG_SF_OFS(x)			(0x2 + (x))
+#define AD5360_REG_SF_READBACK			0x5
+
+#define AD5360_SF_CTRL_PWR_DOWN			BIT(0)
+
+#define AD5360_READBACK_X1A			0x0
+#define AD5360_READBACK_X1B			0x1
+#define AD5360_READBACK_OFFSET			0x2
+#define AD5360_READBACK_GAIN			0x3
+#define AD5360_READBACK_SF			0x4
+
+
+/**
+ * struct ad5360_chip_info - chip specific information
+ * @channel_template:	channel specification template
+ * @num_channels:	number of channels
+ * @channels_per_group:	number of channels per group
+ * @num_vrefs:		number of vref supplies for the chip
+*/
+
+struct ad5360_chip_info {
+	struct iio_chan_spec	channel_template;
+	unsigned int		num_channels;
+	unsigned int		channels_per_group;
+	unsigned int		num_vrefs;
+};
+
+/**
+ * struct ad5360_state - driver instance specific data
+ * @spi:		spi_device
+ * @chip_info:		chip model specific constants, available modes etc
+ * @vref_reg:		vref supply regulators
+ * @ctrl:		control register cache
+ * @data:		spi transfer buffers
+ */
+
+struct ad5360_state {
+	struct spi_device		*spi;
+	const struct ad5360_chip_info	*chip_info;
+	struct regulator_bulk_data	vref_reg[3];
+	unsigned int			ctrl;
+
+	/*
+	 * DMA (thus cache coherency maintenance) requires the
+	 * transfer buffers to live in their own cache lines.
+	 */
+	union {
+		__be32 d32;
+		u8 d8[4];
+	} data[2] ____cacheline_aligned;
+};
+
+enum ad5360_type {
+	ID_AD5360,
+	ID_AD5361,
+	ID_AD5362,
+	ID_AD5363,
+	ID_AD5370,
+	ID_AD5371,
+	ID_AD5372,
+	ID_AD5373,
+};
+
+#define AD5360_CHANNEL(bits) {					\
+	.type = IIO_VOLTAGE,					\
+	.indexed = 1,						\
+	.output = 1,						\
+	.info_mask = (1 << IIO_CHAN_INFO_SCALE_SEPARATE) |	\
+		(1 << IIO_CHAN_INFO_OFFSET_SEPARATE) |		\
+		(1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE) |	\
+		(1 << IIO_CHAN_INFO_CALIBBIAS_SEPARATE),	\
+	.scan_type = IIO_ST('u', (bits), 16, 16 - (bits))	\
+}
+
+static const struct ad5360_chip_info ad5360_chip_info_tbl[] = {
+	[ID_AD5360] = {
+		.channel_template = AD5360_CHANNEL(16),
+		.num_channels = 16,
+		.channels_per_group = 8,
+		.num_vrefs = 2,
+	},
+	[ID_AD5361] = {
+		.channel_template = AD5360_CHANNEL(14),
+		.num_channels = 16,
+		.channels_per_group = 8,
+		.num_vrefs = 2,
+	},
+	[ID_AD5362] = {
+		.channel_template = AD5360_CHANNEL(16),
+		.num_channels = 8,
+		.channels_per_group = 4,
+		.num_vrefs = 2,
+	},
+	[ID_AD5363] = {
+		.channel_template = AD5360_CHANNEL(14),
+		.num_channels = 8,
+		.channels_per_group = 4,
+		.num_vrefs = 2,
+	},
+	[ID_AD5370] = {
+		.channel_template = AD5360_CHANNEL(16),
+		.num_channels = 40,
+		.channels_per_group = 8,
+		.num_vrefs = 2,
+	},
+	[ID_AD5371] = {
+		.channel_template = AD5360_CHANNEL(14),
+		.num_channels = 40,
+		.channels_per_group = 8,
+		.num_vrefs = 3,
+	},
+	[ID_AD5372] = {
+		.channel_template = AD5360_CHANNEL(16),
+		.num_channels = 32,
+		.channels_per_group = 8,
+		.num_vrefs = 2,
+	},
+	[ID_AD5373] = {
+		.channel_template = AD5360_CHANNEL(14),
+		.num_channels = 32,
+		.channels_per_group = 8,
+		.num_vrefs = 2,
+	},
+};
+
+static unsigned int ad5360_get_channel_vref_index(struct ad5360_state *st,
+	unsigned int channel)
+{
+	unsigned int i;
+
+	/* The first groups have their own vref, while the remaining groups
+	 * share the last vref */
+	i = channel / st->chip_info->channels_per_group;
+	if (i >= st->chip_info->num_vrefs)
+		i = st->chip_info->num_vrefs - 1;
+
+	return i;
+}
+
+static int ad5360_get_channel_vref(struct ad5360_state *st,
+	unsigned int channel)
+{
+	unsigned int i = ad5360_get_channel_vref_index(st, channel);
+
+	return regulator_get_voltage(st->vref_reg[i].consumer);
+}
+
+
+static int ad5360_write_unlocked(struct iio_dev *indio_dev,
+	unsigned int cmd, unsigned int addr, unsigned int val,
+	unsigned int shift)
+{
+	struct ad5360_state *st = iio_priv(indio_dev);
+
+	val <<= shift;
+	val |= AD5360_CMD(cmd) | AD5360_ADDR(addr);
+	st->data[0].d32 = cpu_to_be32(val);
+
+	return spi_write(st->spi, &st->data[0].d8[1], 3);
+}
+
+static int ad5360_write(struct iio_dev *indio_dev, unsigned int cmd,
+	unsigned int addr, unsigned int val, unsigned int shift)
+{
+	int ret;
+
+	mutex_lock(&indio_dev->mlock);
+	ret = ad5360_write_unlocked(indio_dev, cmd, addr, val, shift);
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret;
+}
+
+static int ad5360_read(struct iio_dev *indio_dev, unsigned int type,
+	unsigned int addr)
+{
+	struct ad5360_state *st = iio_priv(indio_dev);
+	struct spi_message m;
+	int ret;
+	struct spi_transfer t[] = {
+		{
+			.tx_buf = &st->data[0].d8[1],
+			.len = 3,
+			.cs_change = 1,
+		}, {
+			.rx_buf = &st->data[1].d8[1],
+			.len = 3,
+		},
+	};
+
+	spi_message_init(&m);
+	spi_message_add_tail(&t[0], &m);
+	spi_message_add_tail(&t[1], &m);
+
+	mutex_lock(&indio_dev->mlock);
+
+	st->data[0].d32 = cpu_to_be32(AD5360_CMD(AD5360_CMD_SPECIAL_FUNCTION) |
+		AD5360_ADDR(AD5360_REG_SF_READBACK) |
+		AD5360_READBACK_TYPE(type) |
+		AD5360_READBACK_ADDR(addr));
+
+	ret = spi_sync(st->spi, &m);
+	if (ret >= 0)
+		ret = be32_to_cpu(st->data[1].d32) & 0xffff;
+
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret;
+}
+
+static ssize_t ad5360_read_dac_powerdown(struct device *dev,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ad5360_state *st = iio_priv(indio_dev);
+
+	return sprintf(buf, "%d\n", (bool)(st->ctrl & AD5360_SF_CTRL_PWR_DOWN));
+}
+
+static int ad5360_update_ctrl(struct iio_dev *indio_dev, unsigned int set,
+	unsigned int clr)
+{
+	struct ad5360_state *st = iio_priv(indio_dev);
+	unsigned int ret;
+
+	mutex_lock(&indio_dev->mlock);
+
+	st->ctrl |= set;
+	st->ctrl &= ~clr;
+
+	ret = ad5360_write_unlocked(indio_dev, AD5360_CMD_SPECIAL_FUNCTION,
+			AD5360_REG_SF_CTRL, st->ctrl, 0);
+
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret;
+}
+
+static ssize_t ad5360_write_dac_powerdown(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t len)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	bool pwr_down;
+	int ret;
+
+	ret = strtobool(buf, &pwr_down);
+	if (ret)
+		return ret;
+
+	if (pwr_down)
+		ret = ad5360_update_ctrl(indio_dev, AD5360_SF_CTRL_PWR_DOWN, 0);
+	else
+		ret = ad5360_update_ctrl(indio_dev, 0, AD5360_SF_CTRL_PWR_DOWN);
+
+	return ret ? ret : len;
+}
+
+static IIO_DEVICE_ATTR(out_voltage_powerdown,
+			S_IRUGO | S_IWUSR,
+			ad5360_read_dac_powerdown,
+			ad5360_write_dac_powerdown, 0);
+
+static struct attribute *ad5360_attributes[] = {
+	&iio_dev_attr_out_voltage_powerdown.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group ad5360_attribute_group = {
+	.attrs = ad5360_attributes,
+};
+
+static int ad5360_write_raw(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       int val,
+			       int val2,
+			       long mask)
+{
+	struct ad5360_state *st = iio_priv(indio_dev);
+	int max_val = (1 << chan->scan_type.realbits);
+	unsigned int ofs_index;
+
+	switch (mask) {
+	case 0:
+		if (val >= max_val || val < 0)
+			return -EINVAL;
+
+		return ad5360_write(indio_dev, AD5360_CMD_WRITE_DATA,
+				 chan->address, val, chan->scan_type.shift);
+
+	case (1 << IIO_CHAN_INFO_CALIBBIAS_SEPARATE):
+		if (val >= max_val || val < 0)
+			return -EINVAL;
+
+		return ad5360_write(indio_dev, AD5360_CMD_WRITE_OFFSET,
+				 chan->address, val, chan->scan_type.shift);
+
+	case (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE):
+		if (val >= max_val || val < 0)
+			return -EINVAL;
+
+		return ad5360_write(indio_dev, AD5360_CMD_WRITE_GAIN,
+				 chan->address, val, chan->scan_type.shift);
+
+	case (1 << IIO_CHAN_INFO_OFFSET_SEPARATE):
+		if (val <= -max_val || val > 0)
+			return -EINVAL;
+
+		val = -val;
+
+		/* offset is supposed to have the same scale as raw, but it
+		 * is always 14bits wide, so on a chip where the raw value has
+		 * more bits, we need to shift offset. */
+		val >>= (chan->scan_type.realbits - 14);
+
+		/* There is one DAC offset register per vref. Changing one
+		 * channels offset will also change the offset for all other
+		 * channels which share the same vref supply. */
+		ofs_index = ad5360_get_channel_vref_index(st, chan->channel);
+		return ad5360_write(indio_dev, AD5360_CMD_SPECIAL_FUNCTION,
+				 AD5360_REG_SF_OFS(ofs_index), val, 0);
+	default:
+		break;
+	}
+
+	return -EINVAL;
+}
+
+static int ad5360_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val,
+			   int *val2,
+			   long m)
+{
+	struct ad5360_state *st = iio_priv(indio_dev);
+	unsigned long scale_uv;
+	unsigned int ofs_index;
+	int ret;
+
+	switch (m) {
+	case 0:
+		ret = ad5360_read(indio_dev, AD5360_READBACK_X1A,
+			chan->address);
+		if (ret < 0)
+			return ret;
+		*val = ret >> chan->scan_type.shift;
+		return IIO_VAL_INT;
+	case (1 << IIO_CHAN_INFO_SCALE_SEPARATE):
+		/* vout = 4 * vref * dac_code */
+		scale_uv = ad5360_get_channel_vref(st, chan->channel) * 4 * 100;
+		if (scale_uv < 0)
+			return scale_uv;
+
+		scale_uv >>= (chan->scan_type.realbits);
+		*val =  scale_uv / 100000;
+		*val2 = (scale_uv % 100000) * 10;
+		return IIO_VAL_INT_PLUS_MICRO;
+	case (1 << IIO_CHAN_INFO_CALIBBIAS_SEPARATE):
+		ret = ad5360_read(indio_dev, AD5360_READBACK_OFFSET,
+			chan->address);
+		if (ret < 0)
+			return ret;
+		*val = ret;
+		return IIO_VAL_INT;
+	case (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE):
+		ret = ad5360_read(indio_dev, AD5360_READBACK_GAIN,
+			chan->address);
+		if (ret < 0)
+			return ret;
+		*val = ret;
+		return IIO_VAL_INT;
+	case (1 << IIO_CHAN_INFO_OFFSET_SEPARATE):
+		ofs_index = ad5360_get_channel_vref_index(st, chan->channel);
+		ret = ad5360_read(indio_dev, AD5360_READBACK_SF,
+			AD5360_REG_SF_OFS(ofs_index));
+		if (ret < 0)
+			return ret;
+
+		ret <<= (chan->scan_type.realbits - 14);
+		*val = -ret;
+		return IIO_VAL_INT;
+	}
+
+	return -EINVAL;
+}
+
+static const struct iio_info ad5360_info = {
+	.read_raw = ad5360_read_raw,
+	.write_raw = ad5360_write_raw,
+	.attrs = &ad5360_attribute_group,
+	.driver_module = THIS_MODULE,
+};
+
+static const char * const ad5360_vref_name[] = {
+	 "vref0", "vref1", "vref2"
+};
+
+static int __devinit ad5360_alloc_channels(struct iio_dev *indio_dev)
+{
+	struct ad5360_state *st = iio_priv(indio_dev);
+	struct iio_chan_spec *channels;
+	unsigned int i;
+
+	channels = kcalloc(sizeof(struct iio_chan_spec),
+			st->chip_info->num_channels, GFP_KERNEL);
+
+	if (!channels)
+		return -ENOMEM;
+
+	for (i = 0; i < st->chip_info->num_channels; ++i) {
+		channels[i] = st->chip_info->channel_template;
+		channels[i].channel = i;
+		channels[i].address = AD5360_CHAN_ADDR(i);
+	}
+
+	indio_dev->channels = channels;
+
+	return 0;
+}
+
+static int __devinit ad5360_probe(struct spi_device *spi)
+{
+	enum ad5360_type type = spi_get_device_id(spi)->driver_data;
+	struct iio_dev *indio_dev;
+	struct ad5360_state *st;
+	unsigned int i;
+	int ret;
+
+	indio_dev = iio_allocate_device(sizeof(*st));
+	if (indio_dev == NULL) {
+		dev_err(&spi->dev, "Failed to allocate iio device\n");
+		return  -ENOMEM;
+	}
+
+	st = iio_priv(indio_dev);
+	spi_set_drvdata(spi, indio_dev);
+
+	st->chip_info = &ad5360_chip_info_tbl[type];
+	st->spi = spi;
+
+	indio_dev->dev.parent = &spi->dev;
+	indio_dev->name = spi_get_device_id(spi)->name;
+	indio_dev->info = &ad5360_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->num_channels = st->chip_info->num_channels;
+
+	ret = ad5360_alloc_channels(indio_dev);
+	if (ret) {
+		dev_err(&spi->dev, "Failed to allocate channel spec: %d\n", ret);
+		goto error_free;
+	}
+
+	for (i = 0; i < st->chip_info->num_vrefs; ++i)
+		st->vref_reg[i].supply = ad5360_vref_name[i];
+
+	ret = regulator_bulk_get(&st->spi->dev, st->chip_info->num_vrefs,
+		st->vref_reg);
+	if (ret) {
+		dev_err(&spi->dev, "Failed to request vref regulators: %d\n", ret);
+		goto error_free_channels;
+	}
+
+	ret = regulator_bulk_enable(st->chip_info->num_vrefs, st->vref_reg);
+	if (ret) {
+		dev_err(&spi->dev, "Failed to enable vref regulators: %d\n", ret);
+		goto error_free_reg;
+	}
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(&spi->dev, "Failed to register iio device: %d\n", ret);
+		goto error_disable_reg;
+	}
+
+	return 0;
+
+error_disable_reg:
+	regulator_bulk_disable(st->chip_info->num_vrefs, st->vref_reg);
+error_free_reg:
+	regulator_bulk_free(st->chip_info->num_vrefs, st->vref_reg);
+error_free_channels:
+	kfree(indio_dev->channels);
+error_free:
+	iio_free_device(indio_dev);
+
+	return ret;
+}
+
+static int __devexit ad5360_remove(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev = spi_get_drvdata(spi);
+	struct ad5360_state *st = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+
+	kfree(indio_dev->channels);
+
+	regulator_bulk_disable(st->chip_info->num_vrefs, st->vref_reg);
+	regulator_bulk_free(st->chip_info->num_vrefs, st->vref_reg);
+
+	iio_free_device(indio_dev);
+
+	return 0;
+}
+
+static const struct spi_device_id ad5360_ids[] = {
+	{ "ad5360", ID_AD5360 },
+	{ "ad5361", ID_AD5361 },
+	{ "ad5362", ID_AD5362 },
+	{ "ad5363", ID_AD5363 },
+	{ "ad5370", ID_AD5370 },
+	{ "ad5371", ID_AD5371 },
+	{ "ad5372", ID_AD5372 },
+	{ "ad5373", ID_AD5373 },
+	{}
+};
+MODULE_DEVICE_TABLE(spi, ad5360_ids);
+
+static struct spi_driver ad5360_driver = {
+	.driver = {
+		   .name = "ad5360",
+		   .owner = THIS_MODULE,
+	},
+	.probe = ad5360_probe,
+	.remove = __devexit_p(ad5360_remove),
+	.id_table = ad5360_ids,
+};
+
+static __init int ad5360_spi_init(void)
+{
+	return spi_register_driver(&ad5360_driver);
+}
+module_init(ad5360_spi_init);
+
+static __exit void ad5360_spi_exit(void)
+{
+	spi_unregister_driver(&ad5360_driver);
+}
+module_exit(ad5360_spi_exit);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_DESCRIPTION("Analog Devices AD5360/61/62/63/70/71/72/73 DAC");
+MODULE_LICENSE("GPL v2");