staging:iio:dac: Add AD5064 driver

This patch adds support for the Analog Devices AD6064, AD6064-1, AD6044, AD6024
quad channel digital-to-analog converter devices.

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

3 files changed, 474 insertions, 0 deletions

diff --git a/drivers/staging/iio/dac/Kconfig b/drivers/staging/iio/dac/Kconfig
index 3000156..724af7f 100644
--- a/drivers/staging/iio/dac/Kconfig
+++ b/drivers/staging/iio/dac/Kconfig
@@ -3,6 +3,16 @@
 #
 menu "Digital to analog convertors"
 
+config AD5064
+	tristate "Analog Devices AD5064/64-1/44/24 DAC driver"
+	depends on SPI
+	help
+	  Say yes here to build support for Analog Devices AD5064, AD5064-1,
+	  AD5044, AD5024 Digital to Analog Converter.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ad5064.
+
 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 7f4f2ed..ea49750 100644
--- a/drivers/staging/iio/dac/Makefile
+++ b/drivers/staging/iio/dac/Makefile
@@ -3,6 +3,7 @@
 #
 
 obj-$(CONFIG_AD5624R_SPI) += ad5624r_spi.o
+obj-$(CONFIG_AD5064) += ad5064.o
 obj-$(CONFIG_AD5504) += ad5504.o
 obj-$(CONFIG_AD5446) += ad5446.o
 obj-$(CONFIG_AD5791) += ad5791.o
diff --git a/drivers/staging/iio/dac/ad5064.c b/drivers/staging/iio/dac/ad5064.c
new file mode 100644
index 0000000..24279f2
--- /dev/null
+++ b/drivers/staging/iio/dac/ad5064.c
@@ -0,0 +1,463 @@
+/*
+ * AD5064, AD5064-1, AD5044, AD5024 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 AD5064_DAC_CHANNELS			4
+
+#define AD5064_ADDR(x)				((x) << 20)
+#define AD5064_CMD(x)				((x) << 24)
+
+#define AD5064_ADDR_DAC(chan)			(chan)
+#define AD5064_ADDR_ALL_DAC			0xF
+
+#define AD5064_CMD_WRITE_INPUT_N		0x0
+#define AD5064_CMD_UPDATE_DAC_N			0x1
+#define AD5064_CMD_WRITE_INPUT_N_UPDATE_ALL	0x2
+#define AD5064_CMD_WRITE_INPUT_N_UPDATE_N	0x3
+#define AD5064_CMD_POWERDOWN_DAC		0x4
+#define AD5064_CMD_CLEAR			0x5
+#define AD5064_CMD_LDAC_MASK			0x6
+#define AD5064_CMD_RESET			0x7
+#define AD5064_CMD_DAISY_CHAIN_ENABLE		0x8
+
+#define AD5064_LDAC_PWRDN_NONE			0x0
+#define AD5064_LDAC_PWRDN_1K			0x1
+#define AD5064_LDAC_PWRDN_100K			0x2
+#define AD5064_LDAC_PWRDN_3STATE		0x3
+
+/**
+ * struct ad5064_chip_info - chip specific information
+ * @shared_vref:	whether the vref supply is shared between channels
+ * @channel:		channel specification
+*/
+
+struct ad5064_chip_info {
+	bool shared_vref;
+	struct iio_chan_spec channel[AD5064_DAC_CHANNELS];
+};
+
+/**
+ * struct ad5064_state - driver instance specific data
+ * @spi:		spi_device
+ * @chip_info:		chip model specific constants, available modes etc
+ * @vref_reg:		vref supply regulators
+ * @pwr_down:		whether channel is powered down
+ * @pwr_down_mode:	channel's current power down mode
+ * @dac_cache:		current DAC raw value (chip does not support readback)
+ * @data:		spi transfer buffers
+ */
+
+struct ad5064_state {
+	struct spi_device		*spi;
+	const struct ad5064_chip_info	*chip_info;
+	struct regulator_bulk_data	vref_reg[AD5064_DAC_CHANNELS];
+	bool				pwr_down[AD5064_DAC_CHANNELS];
+	u8				pwr_down_mode[AD5064_DAC_CHANNELS];
+	unsigned int			dac_cache[AD5064_DAC_CHANNELS];
+
+	/*
+	 * DMA (thus cache coherency maintenance) requires the
+	 * transfer buffers to live in their own cache lines.
+	 */
+	__be32 data ____cacheline_aligned;
+};
+
+enum ad5064_type {
+	ID_AD5024,
+	ID_AD5044,
+	ID_AD5064,
+	ID_AD5064_1,
+};
+
+#define AD5064_CHANNEL(chan, bits) {				\
+	.type = IIO_VOLTAGE,					\
+	.indexed = 1,						\
+	.output = 1,						\
+	.channel = (chan),					\
+	.info_mask = (1 << IIO_CHAN_INFO_SCALE_SEPARATE),	\
+	.address = AD5064_ADDR_DAC(chan),			\
+	.scan_type = IIO_ST('u', (bits), 16, 20 - (bits))	\
+}
+
+static const struct ad5064_chip_info ad5064_chip_info_tbl[] = {
+	[ID_AD5024] = {
+		.shared_vref = false,
+		.channel[0] = AD5064_CHANNEL(0, 12),
+		.channel[1] = AD5064_CHANNEL(1, 12),
+		.channel[2] = AD5064_CHANNEL(2, 12),
+		.channel[3] = AD5064_CHANNEL(3, 12),
+	},
+	[ID_AD5044] = {
+		.shared_vref = false,
+		.channel[0] = AD5064_CHANNEL(0, 14),
+		.channel[1] = AD5064_CHANNEL(1, 14),
+		.channel[2] = AD5064_CHANNEL(2, 14),
+		.channel[3] = AD5064_CHANNEL(3, 14),
+	},
+	[ID_AD5064] = {
+		.shared_vref = false,
+		.channel[0] = AD5064_CHANNEL(0, 16),
+		.channel[1] = AD5064_CHANNEL(1, 16),
+		.channel[2] = AD5064_CHANNEL(2, 16),
+		.channel[3] = AD5064_CHANNEL(3, 16),
+	},
+	[ID_AD5064_1] = {
+		.shared_vref = true,
+		.channel[0] = AD5064_CHANNEL(0, 16),
+		.channel[1] = AD5064_CHANNEL(1, 16),
+		.channel[2] = AD5064_CHANNEL(2, 16),
+		.channel[3] = AD5064_CHANNEL(3, 16),
+	},
+};
+
+static int ad5064_spi_write(struct ad5064_state *st, unsigned int cmd,
+	unsigned int addr, unsigned int val, unsigned int shift)
+{
+	val <<= shift;
+
+	st->data = cpu_to_be32(AD5064_CMD(cmd) | AD5064_ADDR(addr) | val);
+
+	return spi_write(st->spi, &st->data, sizeof(st->data));
+}
+
+static int ad5064_sync_powerdown_mode(struct ad5064_state *st,
+	unsigned int channel)
+{
+	unsigned int val;
+	int ret;
+
+	val = (0x1 << channel);
+
+	if (st->pwr_down[channel])
+		val |= st->pwr_down_mode[channel] << 8;
+
+	ret = ad5064_spi_write(st, AD5064_CMD_POWERDOWN_DAC, 0, val, 0);
+
+	return ret;
+}
+
+static const char ad5064_powerdown_modes[][15] = {
+	[AD5064_LDAC_PWRDN_NONE]	= "",
+	[AD5064_LDAC_PWRDN_1K]		= "1kohm_to_gnd",
+	[AD5064_LDAC_PWRDN_100K]	= "100kohm_to_gnd",
+	[AD5064_LDAC_PWRDN_3STATE]	= "three_state",
+};
+
+static ssize_t ad5064_read_powerdown_mode(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ad5064_state *st = iio_priv(indio_dev);
+
+	return sprintf(buf, "%s\n",
+		ad5064_powerdown_modes[st->pwr_down_mode[this_attr->address]]);
+}
+
+static ssize_t ad5064_write_powerdown_mode(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t len)
+{
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ad5064_state *st = iio_priv(indio_dev);
+	unsigned int mode, i;
+	int ret;
+
+	mode = 0;
+
+	for (i = 1; i < ARRAY_SIZE(ad5064_powerdown_modes); ++i) {
+		if (sysfs_streq(buf, ad5064_powerdown_modes[i])) {
+			mode = i;
+			break;
+		}
+	}
+	if (mode == 0)
+		return  -EINVAL;
+
+	mutex_lock(&indio_dev->mlock);
+	st->pwr_down_mode[this_attr->address] = mode;
+
+	ret = ad5064_sync_powerdown_mode(st, this_attr->address);
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret ? ret : len;
+}
+
+static ssize_t ad5064_read_dac_powerdown(struct device *dev,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ad5064_state *st = iio_priv(indio_dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+
+	return sprintf(buf, "%d\n", st->pwr_down[this_attr->address]);
+}
+
+static ssize_t ad5064_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);
+	struct ad5064_state *st = iio_priv(indio_dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	bool pwr_down;
+	int ret;
+
+	ret = strtobool(buf, &pwr_down);
+	if (ret)
+		return ret;
+
+	mutex_lock(&indio_dev->mlock);
+	st->pwr_down[this_attr->address] = pwr_down;
+
+	ret = ad5064_sync_powerdown_mode(st, this_attr->address);
+	mutex_unlock(&indio_dev->mlock);
+	return ret ? ret : len;
+}
+
+static IIO_CONST_ATTR(out_voltage_powerdown_mode_available,
+			"1kohm_to_gnd 100kohm_to_gnd three_state");
+
+#define IIO_DEV_ATTR_DAC_POWERDOWN_MODE(_chan) \
+	IIO_DEVICE_ATTR(out_voltage##_chan##_powerdown_mode, \
+			S_IRUGO | S_IWUSR, \
+			ad5064_read_powerdown_mode, \
+			ad5064_write_powerdown_mode, _chan);
+
+#define IIO_DEV_ATTR_DAC_POWERDOWN(_chan)				\
+	IIO_DEVICE_ATTR(out_voltage##_chan##_powerdown,			\
+			S_IRUGO | S_IWUSR,				\
+			ad5064_read_dac_powerdown,			\
+			ad5064_write_dac_powerdown, _chan)
+
+static IIO_DEV_ATTR_DAC_POWERDOWN(0);
+static IIO_DEV_ATTR_DAC_POWERDOWN_MODE(0);
+static IIO_DEV_ATTR_DAC_POWERDOWN(1);
+static IIO_DEV_ATTR_DAC_POWERDOWN_MODE(1);
+static IIO_DEV_ATTR_DAC_POWERDOWN(2);
+static IIO_DEV_ATTR_DAC_POWERDOWN_MODE(2);
+static IIO_DEV_ATTR_DAC_POWERDOWN(3);
+static IIO_DEV_ATTR_DAC_POWERDOWN_MODE(3);
+
+static struct attribute *ad5064_attributes[] = {
+	&iio_dev_attr_out_voltage0_powerdown.dev_attr.attr,
+	&iio_dev_attr_out_voltage1_powerdown.dev_attr.attr,
+	&iio_dev_attr_out_voltage2_powerdown.dev_attr.attr,
+	&iio_dev_attr_out_voltage3_powerdown.dev_attr.attr,
+	&iio_dev_attr_out_voltage0_powerdown_mode.dev_attr.attr,
+	&iio_dev_attr_out_voltage1_powerdown_mode.dev_attr.attr,
+	&iio_dev_attr_out_voltage2_powerdown_mode.dev_attr.attr,
+	&iio_dev_attr_out_voltage3_powerdown_mode.dev_attr.attr,
+	&iio_const_attr_out_voltage_powerdown_mode_available.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group ad5064_attribute_group = {
+	.attrs = ad5064_attributes,
+};
+
+static int ad5064_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val,
+			   int *val2,
+			   long m)
+{
+	struct ad5064_state *st = iio_priv(indio_dev);
+	unsigned long scale_uv;
+	unsigned int vref;
+
+	switch (m) {
+	case 0:
+		*val = st->dac_cache[chan->channel];
+		return IIO_VAL_INT;
+	case (1 << IIO_CHAN_INFO_SCALE_SEPARATE):
+		vref = st->chip_info->shared_vref ? 0 : chan->channel;
+		scale_uv = regulator_get_voltage(st->vref_reg[vref].consumer);
+		if (scale_uv < 0)
+			return scale_uv;
+
+		scale_uv = (scale_uv * 100) >> chan->scan_type.realbits;
+		*val =  scale_uv / 100000;
+		*val2 = (scale_uv % 100000) * 10;
+		return IIO_VAL_INT_PLUS_MICRO;
+	default:
+		break;
+	}
+	return -EINVAL;
+}
+
+static int ad5064_write_raw(struct iio_dev *indio_dev,
+	struct iio_chan_spec const *chan, int val, int val2, long mask)
+{
+	struct ad5064_state *st = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case 0:
+		if (val > (1 << chan->scan_type.realbits) || val < 0)
+			return -EINVAL;
+
+		mutex_lock(&indio_dev->mlock);
+		ret = ad5064_spi_write(st, AD5064_CMD_WRITE_INPUT_N_UPDATE_N,
+				chan->address, val, chan->scan_type.shift);
+		if (ret == 0)
+			st->dac_cache[chan->channel] = val;
+		mutex_unlock(&indio_dev->mlock);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+static const struct iio_info ad5064_info = {
+	.read_raw = ad5064_read_raw,
+	.write_raw = ad5064_write_raw,
+	.attrs = &ad5064_attribute_group,
+	.driver_module = THIS_MODULE,
+};
+
+static inline unsigned int ad5064_num_vref(struct ad5064_state *st)
+{
+	return st->chip_info->shared_vref ? 1 : AD5064_DAC_CHANNELS;
+}
+
+static const char * const ad5064_vref_names[] = {
+	"vrefA",
+	"vrefB",
+	"vrefC",
+	"vrefD",
+};
+
+static const char * const ad5064_vref_name(struct ad5064_state *st,
+	unsigned int vref)
+{
+	return st->chip_info->shared_vref ? "vref" : ad5064_vref_names[vref];
+}
+
+static int __devinit ad5064_probe(struct spi_device *spi)
+{
+	enum ad5064_type type = spi_get_device_id(spi)->driver_data;
+	struct iio_dev *indio_dev;
+	struct ad5064_state *st;
+	unsigned int i;
+	int ret;
+
+	indio_dev = iio_allocate_device(sizeof(*st));
+	if (indio_dev == NULL)
+		return  -ENOMEM;
+
+	st = iio_priv(indio_dev);
+	spi_set_drvdata(spi, indio_dev);
+
+	st->chip_info = &ad5064_chip_info_tbl[type];
+	st->spi = spi;
+
+	for (i = 0; i < ad5064_num_vref(st); ++i)
+		st->vref_reg[i].supply = ad5064_vref_name(st, i);
+
+	ret = regulator_bulk_get(&st->spi->dev, ad5064_num_vref(st),
+		st->vref_reg);
+	if (ret)
+		goto error_free;
+
+	ret = regulator_bulk_enable(ad5064_num_vref(st), st->vref_reg);
+	if (ret)
+		goto error_free_reg;
+
+	for (i = 0; i < AD5064_DAC_CHANNELS; ++i) {
+		st->pwr_down_mode[i] = AD5064_LDAC_PWRDN_1K;
+		st->dac_cache[i] = 0x8000;
+	}
+
+	indio_dev->dev.parent = &spi->dev;
+	indio_dev->name = spi_get_device_id(spi)->name;
+	indio_dev->info = &ad5064_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = st->chip_info->channel;
+	indio_dev->num_channels = AD5064_DAC_CHANNELS;
+
+	ret = iio_device_register(indio_dev);
+	if (ret)
+		goto error_disable_reg;
+
+	return 0;
+
+error_disable_reg:
+	regulator_bulk_disable(ad5064_num_vref(st), st->vref_reg);
+error_free_reg:
+	regulator_bulk_free(ad5064_num_vref(st), st->vref_reg);
+error_free:
+	iio_free_device(indio_dev);
+
+	return ret;
+}
+
+
+static int __devexit ad5064_remove(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev = spi_get_drvdata(spi);
+	struct ad5064_state *st = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+
+	regulator_bulk_disable(ad5064_num_vref(st), st->vref_reg);
+	regulator_bulk_free(ad5064_num_vref(st), st->vref_reg);
+
+	iio_free_device(indio_dev);
+
+	return 0;
+}
+
+static const struct spi_device_id ad5064_id[] = {
+	{"ad5024", ID_AD5024},
+	{"ad5044", ID_AD5044},
+	{"ad5064", ID_AD5064},
+	{"ad5064-1", ID_AD5064_1},
+	{}
+};
+MODULE_DEVICE_TABLE(spi, ad5064_id);
+
+static struct spi_driver ad5064_driver = {
+	.driver = {
+		   .name = "ad5064",
+		   .owner = THIS_MODULE,
+	},
+	.probe = ad5064_probe,
+	.remove = __devexit_p(ad5064_remove),
+	.id_table = ad5064_id,
+};
+
+static __init int ad5064_spi_init(void)
+{
+	return spi_register_driver(&ad5064_driver);
+}
+module_init(ad5064_spi_init);
+
+static __exit void ad5064_spi_exit(void)
+{
+	spi_unregister_driver(&ad5064_driver);
+}
+module_exit(ad5064_spi_exit);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_DESCRIPTION("Analog Devices AD5064/64-1/44/24 DAC");
+MODULE_LICENSE("GPL v2");