iio: dac: New driver for AD5686R, AD5685R, AD5684R Digital to analog converters

New driver for AD5686R, AD5685R, AD5684R Quad channel digital to analog converters

Changes since V1:

drop header file
use strtobool()
Fix dev attribute macros
Reorder probe() function

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/staging/iio/dac/Kconfig b/drivers/staging/iio/dac/Kconfig
index d5a5556..7ddae35 100644
--- a/drivers/staging/iio/dac/Kconfig
+++ b/drivers/staging/iio/dac/Kconfig
@@ -42,6 +42,17 @@
 	  To compile this driver as a module, choose M here: the
 	  module will be called ad5791.
 
+config AD5686
+	tristate "Analog Devices AD5686R/AD5685R/AD5684R DAC SPI driver"
+	depends on SPI
+	help
+	  Say yes here to build support for Analog Devices AD5686R, AD5685R,
+	  AD5684R, AD5791 Voltage Output Digital to
+	  Analog Converter.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ad5686.
+
 config MAX517
 	tristate "Maxim MAX517/518/519 DAC driver"
 	depends on I2C && EXPERIMENTAL
diff --git a/drivers/staging/iio/dac/Makefile b/drivers/staging/iio/dac/Makefile
index 83196de..7f4f2ed 100644
--- a/drivers/staging/iio/dac/Makefile
+++ b/drivers/staging/iio/dac/Makefile
@@ -6,4 +6,5 @@
 obj-$(CONFIG_AD5504) += ad5504.o
 obj-$(CONFIG_AD5446) += ad5446.o
 obj-$(CONFIG_AD5791) += ad5791.o
+obj-$(CONFIG_AD5686) += ad5686.o
 obj-$(CONFIG_MAX517) += max517.o
diff --git a/drivers/staging/iio/dac/ad5686.c b/drivers/staging/iio/dac/ad5686.c
new file mode 100644
index 0000000..fd67cfa
--- /dev/null
+++ b/drivers/staging/iio/dac/ad5686.c
@@ -0,0 +1,497 @@
+/*
+ * AD5686R, AD5685R, AD5684R Digital to analog converters  driver
+ *
+ * Copyright 2011 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/gpio.h>
+#include <linux/fs.h>
+#include <linux/device.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 AD5686_DAC_CHANNELS			4
+
+#define AD5686_ADDR(x)				((x) << 16)
+#define AD5686_CMD(x)				((x) << 20)
+
+#define AD5686_ADDR_DAC0			0x1
+#define AD5686_ADDR_DAC1			0x2
+#define AD5686_ADDR_DAC2			0x4
+#define AD5686_ADDR_DAC3			0x8
+#define AD5686_ADDR_ALL_DAC			0xF
+
+#define AD5686_CMD_NOOP				0x0
+#define AD5686_CMD_WRITE_INPUT_N		0x1
+#define AD5686_CMD_UPDATE_DAC_N			0x2
+#define AD5686_CMD_WRITE_INPUT_N_UPDATE_N	0x3
+#define AD5686_CMD_POWERDOWN_DAC		0x4
+#define AD5686_CMD_LDAC_MASK			0x5
+#define AD5686_CMD_RESET			0x6
+#define AD5686_CMD_INTERNAL_REFER_SETUP		0x7
+#define AD5686_CMD_DAISY_CHAIN_ENABLE		0x8
+#define AD5686_CMD_READBACK_ENABLE		0x9
+
+#define AD5686_LDAC_PWRDN_NONE			0x0
+#define AD5686_LDAC_PWRDN_1K			0x1
+#define AD5686_LDAC_PWRDN_100K			0x2
+#define AD5686_LDAC_PWRDN_3STATE		0x3
+
+/**
+ * struct ad5686_chip_info - chip specific information
+ * @int_vref_mv:	AD5620/40/60: the internal reference voltage
+ * @channel:		channel specification
+*/
+
+struct ad5686_chip_info {
+	u16				int_vref_mv;
+	struct iio_chan_spec		channel[AD5686_DAC_CHANNELS];
+};
+
+/**
+ * struct ad5446_state - driver instance specific data
+ * @spi:		spi_device
+ * @chip_info:		chip model specific constants, available modes etc
+ * @reg:		supply regulator
+ * @vref_mv:		actual reference voltage used
+ * @pwr_down_mask:	power down mask
+ * @pwr_down_mode:	current power down mode
+ * @data:		spi transfer buffers
+ */
+
+struct ad5686_state {
+	struct spi_device		*spi;
+	const struct ad5686_chip_info	*chip_info;
+	struct regulator		*reg;
+	unsigned short			vref_mv;
+	unsigned			pwr_down_mask;
+	unsigned			pwr_down_mode;
+	/*
+	 * DMA (thus cache coherency maintenance) requires the
+	 * transfer buffers to live in their own cache lines.
+	 */
+
+	union {
+		u32 d32;
+		u8 d8[4];
+	} data[3] ____cacheline_aligned;
+};
+
+/**
+ * ad5686_supported_device_ids:
+ */
+
+enum ad5686_supported_device_ids {
+	ID_AD5684,
+	ID_AD5685,
+	ID_AD5686,
+};
+
+static const struct ad5686_chip_info ad5686_chip_info_tbl[] = {
+	[ID_AD5684] = {
+		.channel[0] = IIO_CHAN(IIO_OUT, 0, 1, 0, NULL, 0, 0,
+				    (1 << IIO_CHAN_INFO_SCALE_SHARED),
+				    AD5686_ADDR_DAC0,
+				    0, IIO_ST('u', 12, 16, 4), 0),
+		.channel[1] = IIO_CHAN(IIO_OUT, 0, 1, 0, NULL, 1, 0,
+				    (1 << IIO_CHAN_INFO_SCALE_SHARED),
+				    AD5686_ADDR_DAC1,
+				    1, IIO_ST('u', 12, 16, 4), 0),
+		.channel[2] = IIO_CHAN(IIO_OUT, 0, 1, 0, NULL, 2, 0,
+				    (1 << IIO_CHAN_INFO_SCALE_SHARED),
+				    AD5686_ADDR_DAC2,
+				    2, IIO_ST('u', 12, 16, 4), 0),
+		.channel[3] = IIO_CHAN(IIO_OUT, 0, 1, 0, NULL, 3, 0,
+				    (1 << IIO_CHAN_INFO_SCALE_SHARED),
+				    AD5686_ADDR_DAC3,
+				    3, IIO_ST('u', 12, 16, 4), 0),
+		.int_vref_mv = 2500,
+	},
+	[ID_AD5685] = {
+		.channel[0] = IIO_CHAN(IIO_OUT, 0, 1, 0, NULL, 0, 0,
+				    (1 << IIO_CHAN_INFO_SCALE_SHARED),
+				    AD5686_ADDR_DAC0,
+				    0, IIO_ST('u', 14, 16, 2), 0),
+		.channel[1] = IIO_CHAN(IIO_OUT, 0, 1, 0, NULL, 1, 0,
+				    (1 << IIO_CHAN_INFO_SCALE_SHARED),
+				    AD5686_ADDR_DAC1,
+				    1, IIO_ST('u', 14, 16, 2), 0),
+		.channel[2] = IIO_CHAN(IIO_OUT, 0, 1, 0, NULL, 2, 0,
+				    (1 << IIO_CHAN_INFO_SCALE_SHARED),
+				    AD5686_ADDR_DAC2,
+				    2, IIO_ST('u', 14, 16, 2), 0),
+		.channel[3] = IIO_CHAN(IIO_OUT, 0, 1, 0, NULL, 3, 0,
+				    (1 << IIO_CHAN_INFO_SCALE_SHARED),
+				    AD5686_ADDR_DAC3,
+				    3, IIO_ST('u', 14, 16, 2), 0),
+		.int_vref_mv = 2500,
+	},
+	[ID_AD5686] = {
+		.channel[0] = IIO_CHAN(IIO_OUT, 0, 1, 0, NULL, 0, 0,
+				    (1 << IIO_CHAN_INFO_SCALE_SHARED),
+				    AD5686_ADDR_DAC0,
+				    0, IIO_ST('u', 16, 16, 0), 0),
+		.channel[1] = IIO_CHAN(IIO_OUT, 0, 1, 0, NULL, 1, 0,
+				    (1 << IIO_CHAN_INFO_SCALE_SHARED),
+				    AD5686_ADDR_DAC1,
+				    1, IIO_ST('u', 16, 16, 0), 0),
+		.channel[2] = IIO_CHAN(IIO_OUT, 0, 1, 0, NULL, 2, 0,
+				    (1 << IIO_CHAN_INFO_SCALE_SHARED),
+				    AD5686_ADDR_DAC2,
+				    2, IIO_ST('u', 16, 16, 0), 0),
+		.channel[3] = IIO_CHAN(IIO_OUT, 0, 1, 0, NULL, 3, 0,
+				    (1 << IIO_CHAN_INFO_SCALE_SHARED),
+				    AD5686_ADDR_DAC3,
+				    3, IIO_ST('u', 16, 16, 0), 0),
+		.int_vref_mv = 2500,
+	},
+};
+
+static int ad5686_spi_write(struct ad5686_state *st,
+			     u8 cmd, u8 addr, u16 val, u8 shift)
+{
+	val <<= shift;
+
+	st->data[0].d32 = cpu_to_be32(AD5686_CMD(cmd) |
+			      AD5686_ADDR(addr) |
+			      val);
+
+	return spi_write(st->spi, &st->data[0].d8[1], 3);
+}
+
+static int ad5686_spi_read(struct ad5686_state *st, u8 addr)
+{
+	struct spi_transfer t[] = {
+		{
+			.tx_buf = &st->data[0].d8[1],
+			.len = 3,
+			.cs_change = 1,
+		}, {
+			.tx_buf = &st->data[1].d8[1],
+			.rx_buf = &st->data[2].d8[1],
+			.len = 3,
+		},
+	};
+	struct spi_message m;
+	int ret;
+
+	spi_message_init(&m);
+	spi_message_add_tail(&t[0], &m);
+	spi_message_add_tail(&t[1], &m);
+
+	st->data[0].d32 = cpu_to_be32(AD5686_CMD(AD5686_CMD_READBACK_ENABLE) |
+			      AD5686_ADDR(addr));
+	st->data[1].d32 = cpu_to_be32(AD5686_CMD(AD5686_CMD_NOOP));
+
+	ret = spi_sync(st->spi, &m);
+	if (ret < 0)
+		return ret;
+
+	return be32_to_cpu(st->data[2].d32);
+}
+
+static ssize_t ad5686_read_powerdown_mode(struct device *dev,
+				      struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ad5686_state *st = iio_priv(indio_dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+
+	char mode[][15] = {"", "1kohm_to_gnd", "100kohm_to_gnd", "three_state"};
+
+	return sprintf(buf, "%s\n", mode[(st->pwr_down_mode >>
+					 (this_attr->address * 2)) & 0x3]);
+}
+
+static ssize_t ad5686_write_powerdown_mode(struct device *dev,
+				       struct device_attribute *attr,
+				       const char *buf, size_t len)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ad5686_state *st = iio_priv(indio_dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	unsigned mode;
+
+	if (sysfs_streq(buf, "1kohm_to_gnd"))
+		mode = AD5686_LDAC_PWRDN_1K;
+	else if (sysfs_streq(buf, "100kohm_to_gnd"))
+		mode = AD5686_LDAC_PWRDN_100K;
+	else if (sysfs_streq(buf, "three_state"))
+		mode = AD5686_LDAC_PWRDN_3STATE;
+	else
+		return  -EINVAL;
+
+	st->pwr_down_mode &= ~(0x3 << (this_attr->address * 2));
+	st->pwr_down_mode |= (mode << (this_attr->address * 2));
+
+	return len;
+}
+
+static ssize_t ad5686_read_dac_powerdown(struct device *dev,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ad5686_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_mask &
+			(0x3 << (this_attr->address * 2))));
+}
+
+static ssize_t ad5686_write_dac_powerdown(struct device *dev,
+					    struct device_attribute *attr,
+					    const char *buf, size_t len)
+{
+	bool readin;
+	int ret;
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ad5686_state *st = iio_priv(indio_dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+
+	ret = strtobool(buf, &readin);
+	if (ret)
+		return ret;
+
+	if (readin == true)
+		st->pwr_down_mask |= (0x3 << (this_attr->address * 2));
+	else
+		st->pwr_down_mask &= ~(0x3 << (this_attr->address * 2));
+
+	ret = ad5686_spi_write(st, AD5686_CMD_POWERDOWN_DAC, 0,
+			       st->pwr_down_mask & st->pwr_down_mode, 0);
+
+	return ret ? ret : len;
+}
+
+static IIO_CONST_ATTR(out_powerdown_mode_available,
+			"1kohm_to_gnd 100kohm_to_gnd three_state");
+
+#define IIO_DEV_ATTR_DAC_POWERDOWN_MODE(_num) \
+	IIO_DEVICE_ATTR(out##_num##_powerdown_mode, S_IRUGO | S_IWUSR,	\
+			ad5686_read_powerdown_mode,			\
+			ad5686_write_powerdown_mode, _num)
+
+static IIO_DEV_ATTR_DAC_POWERDOWN_MODE(0);
+static IIO_DEV_ATTR_DAC_POWERDOWN_MODE(1);
+static IIO_DEV_ATTR_DAC_POWERDOWN_MODE(2);
+static IIO_DEV_ATTR_DAC_POWERDOWN_MODE(3);
+
+#define IIO_DEV_ATTR_DAC_POWERDOWN(_num)	\
+	IIO_DEVICE_ATTR(out##_num##_powerdown, S_IRUGO | S_IWUSR,	\
+			ad5686_read_dac_powerdown,			\
+			ad5686_write_dac_powerdown, _num)
+
+static IIO_DEV_ATTR_DAC_POWERDOWN(0);
+static IIO_DEV_ATTR_DAC_POWERDOWN(1);
+static IIO_DEV_ATTR_DAC_POWERDOWN(2);
+static IIO_DEV_ATTR_DAC_POWERDOWN(3);
+
+static struct attribute *ad5686_attributes[] = {
+	&iio_dev_attr_out0_powerdown.dev_attr.attr,
+	&iio_dev_attr_out1_powerdown.dev_attr.attr,
+	&iio_dev_attr_out2_powerdown.dev_attr.attr,
+	&iio_dev_attr_out3_powerdown.dev_attr.attr,
+	&iio_dev_attr_out0_powerdown_mode.dev_attr.attr,
+	&iio_dev_attr_out1_powerdown_mode.dev_attr.attr,
+	&iio_dev_attr_out2_powerdown_mode.dev_attr.attr,
+	&iio_dev_attr_out3_powerdown_mode.dev_attr.attr,
+	&iio_const_attr_out_powerdown_mode_available.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group ad5686_attribute_group = {
+	.attrs = ad5686_attributes,
+};
+
+static int ad5686_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val,
+			   int *val2,
+			   long m)
+{
+	struct ad5686_state *st = iio_priv(indio_dev);
+	unsigned long scale_uv;
+	int ret;
+
+	switch (m) {
+	case 0:
+		mutex_lock(&indio_dev->mlock);
+		ret = ad5686_spi_read(st, chan->address);
+		mutex_unlock(&indio_dev->mlock);
+		if (ret < 0)
+			return ret;
+		*val = ret;
+		return IIO_VAL_INT;
+		break;
+	case (1 << IIO_CHAN_INFO_SCALE_SHARED):
+		scale_uv = (st->vref_mv * 100000)
+			>> (chan->scan_type.realbits);
+		*val =  scale_uv / 100000;
+		*val2 = (scale_uv % 100000) * 10;
+		return IIO_VAL_INT_PLUS_MICRO;
+
+	}
+	return -EINVAL;
+}
+
+static int ad5686_write_raw(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       int val,
+			       int val2,
+			       long mask)
+{
+	struct ad5686_state *st = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case 0:
+		if (val > (1 << chan->scan_type.realbits))
+			return -EINVAL;
+
+		mutex_lock(&indio_dev->mlock);
+		ret = ad5686_spi_write(st,
+				 AD5686_CMD_WRITE_INPUT_N_UPDATE_N,
+				 chan->address,
+				 val,
+				 chan->scan_type.shift);
+		mutex_unlock(&indio_dev->mlock);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+static const struct iio_info ad5686_info = {
+	.read_raw = ad5686_read_raw,
+	.write_raw = ad5686_write_raw,
+	.attrs = &ad5686_attribute_group,
+	.driver_module = THIS_MODULE,
+};
+
+static int __devinit ad5686_probe(struct spi_device *spi)
+{
+	struct ad5686_state *st;
+	struct iio_dev *indio_dev;
+	int ret, regdone = 0, voltage_uv = 0;
+
+	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->reg = regulator_get(&spi->dev, "vcc");
+	if (!IS_ERR(st->reg)) {
+		ret = regulator_enable(st->reg);
+		if (ret)
+			goto error_put_reg;
+
+		voltage_uv = regulator_get_voltage(st->reg);
+	}
+
+	st->chip_info =
+		&ad5686_chip_info_tbl[spi_get_device_id(spi)->driver_data];
+
+	if (voltage_uv)
+		st->vref_mv = voltage_uv / 1000;
+	else
+		st->vref_mv = st->chip_info->int_vref_mv;
+
+	st->spi = spi;
+
+	indio_dev->dev.parent = &spi->dev;
+	indio_dev->name = spi_get_device_id(spi)->name;
+	indio_dev->info = &ad5686_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = st->chip_info->channel;
+	indio_dev->num_channels = AD5686_DAC_CHANNELS;
+
+	ret = iio_device_register(indio_dev);
+	if (ret)
+		goto error_disable_reg;
+
+	regdone = 1;
+	ret = ad5686_spi_write(st, AD5686_CMD_INTERNAL_REFER_SETUP, 0,
+				!!voltage_uv, 0);
+	if (ret)
+		goto error_disable_reg;
+
+	return 0;
+
+error_disable_reg:
+	if (!IS_ERR(st->reg))
+		regulator_disable(st->reg);
+error_put_reg:
+	if (!IS_ERR(st->reg))
+		regulator_put(st->reg);
+
+	if (regdone)
+		iio_device_unregister(indio_dev);
+	else
+		iio_free_device(indio_dev);
+
+	return ret;
+}
+
+static int __devexit ad5686_remove(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev = spi_get_drvdata(spi);
+	struct ad5686_state *st = iio_priv(indio_dev);
+	struct regulator *reg = st->reg;
+
+	if (!IS_ERR(reg)) {
+		regulator_disable(reg);
+		regulator_put(reg);
+	}
+
+	iio_device_unregister(indio_dev);
+
+	return 0;
+}
+
+static const struct spi_device_id ad5686_id[] = {
+	{"ad5684", ID_AD5684},
+	{"ad5685", ID_AD5685},
+	{"ad5686", ID_AD5686},
+	{}
+};
+
+static struct spi_driver ad5686_driver = {
+	.driver = {
+		   .name = "ad5686",
+		   .owner = THIS_MODULE,
+		   },
+	.probe = ad5686_probe,
+	.remove = __devexit_p(ad5686_remove),
+	.id_table = ad5686_id,
+};
+
+static __init int ad5686_spi_init(void)
+{
+	return spi_register_driver(&ad5686_driver);
+}
+module_init(ad5686_spi_init);
+
+static __exit void ad5686_spi_exit(void)
+{
+	spi_unregister_driver(&ad5686_driver);
+}
+module_exit(ad5686_spi_exit);
+
+MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
+MODULE_DESCRIPTION("Analog Devices AD5686/85/84 DAC");
+MODULE_LICENSE("GPL v2");