staging:iio:dac: Add AD5764 driver

This patch adds support for the Analog Devices AD5764, AD5764R, AD5744, AD5744R
quad channel analog-to-digital converter.

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

drivers/staging/iio/dac/Kconfig

···
 	  To compile this driver as a module, choose M here: the
 	  module will be called ad5504.
 
+config AD5764
+	tristate "Analog Devices AD5764/64R/44/44R DAC driver"
+	depends on SPI_MASTER
+	help
+	  Say yes here to build support for Analog Devices AD5764, AD5764R, AD5744,
+	  AD5744R Digital to Analog Converter.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ad5764.
+
 config AD5791
 	tristate "Analog Devices AD5760/AD5780/AD5781/AD5791 DAC SPI driver"
 	depends on SPI

drivers/staging/iio/dac/Makefile

···
 obj-$(CONFIG_AD5064) += ad5064.o
 obj-$(CONFIG_AD5504) += ad5504.o
 obj-$(CONFIG_AD5446) += ad5446.o
+obj-$(CONFIG_AD5764) += ad5764.o
 obj-$(CONFIG_AD5791) += ad5791.o
 obj-$(CONFIG_AD5686) += ad5686.o
 obj-$(CONFIG_MAX517) += max517.o

drivers/staging/iio/dac/ad5764.c

···
+/*
+ * Analog devices AD5764, AD5764R, AD5744, AD5744R quad-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 AD5764_REG_SF_NOP			0x0
+#define AD5764_REG_SF_CONFIG			0x1
+#define AD5764_REG_SF_CLEAR			0x4
+#define AD5764_REG_SF_LOAD			0x5
+#define AD5764_REG_DATA(x)			((2 << 3) | (x))
+#define AD5764_REG_COARSE_GAIN(x)		((3 << 3) | (x))
+#define AD5764_REG_FINE_GAIN(x)			((4 << 3) | (x))
+#define AD5764_REG_OFFSET(x)			((5 << 3) | (x))
+
+#define AD5764_NUM_CHANNELS 4
+
+/**
+ * struct ad5764_chip_info - chip specific information
+ * @int_vref:	Value of the internal reference voltage in uV - 0 if external
+ *		reference voltage is used
+ * @channel	channel specification
+*/
+
+struct ad5764_chip_info {
+	unsigned long int_vref;
+	const struct iio_chan_spec *channels;
+};
+
+/**
+ * struct ad5764_state - driver instance specific data
+ * @spi:		spi_device
+ * @chip_info:		chip info
+ * @vref_reg:		vref supply regulators
+ * @data:		spi transfer buffers
+ */
+
+struct ad5764_state {
+	struct spi_device		*spi;
+	const struct ad5764_chip_info	*chip_info;
+	struct regulator_bulk_data	vref_reg[2];
+
+	/*
+	 * 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 ad5764_type {
+	ID_AD5744,
+	ID_AD5744R,
+	ID_AD5764,
+	ID_AD5764R,
+};
+
+#define AD5764_CHANNEL(_chan, _bits) {				\
+	.type = IIO_VOLTAGE,					\
+	.indexed = 1,						\
+	.output = 1,						\
+	.channel = (_chan),					\
+	.address = (_chan),					\
+	.info_mask = IIO_CHAN_INFO_OFFSET_SHARED_BIT |		\
+		IIO_CHAN_INFO_SCALE_SEPARATE_BIT |		\
+		IIO_CHAN_INFO_CALIBSCALE_SEPARATE_BIT |		\
+		IIO_CHAN_INFO_CALIBBIAS_SEPARATE_BIT,		\
+	.scan_type = IIO_ST('u', (_bits), 16, 16 - (_bits))	\
+}
+
+#define DECLARE_AD5764_CHANNELS(_name, _bits) \
+const struct iio_chan_spec _name##_channels[] = { \
+	AD5764_CHANNEL(0, (_bits)), \
+	AD5764_CHANNEL(1, (_bits)), \
+	AD5764_CHANNEL(2, (_bits)), \
+	AD5764_CHANNEL(3, (_bits)), \
+};
+
+static DECLARE_AD5764_CHANNELS(ad5764, 16);
+static DECLARE_AD5764_CHANNELS(ad5744, 14);
+
+static const struct ad5764_chip_info ad5764_chip_infos[] = {
+	[ID_AD5744] = {
+		.int_vref = 0,
+		.channels = ad5744_channels,
+	},
+	[ID_AD5744R] = {
+		.int_vref = 5000000,
+		.channels = ad5744_channels,
+	},
+	[ID_AD5764] = {
+		.int_vref = 0,
+		.channels = ad5764_channels,
+	},
+	[ID_AD5764R] = {
+		.int_vref = 5000000,
+		.channels = ad5764_channels,
+	},
+};
+
+static int ad5764_write(struct iio_dev *indio_dev, unsigned int reg,
+	unsigned int val)
+{
+	struct ad5764_state *st = iio_priv(indio_dev);
+	int ret;
+
+	mutex_lock(&indio_dev->mlock);
+	st->data[0].d32 = cpu_to_be32((reg << 16) | val);
+
+	ret = spi_write(st->spi, &st->data[0].d8[1], 3);
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret;
+}
+
+static int ad5764_read(struct iio_dev *indio_dev, unsigned int reg,
+	unsigned int *val)
+{
+	struct ad5764_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((1 << 23) | (reg << 16));
+
+	ret = spi_sync(st->spi, &m);
+	if (ret >= 0)
+		*val = be32_to_cpu(st->data[1].d32) & 0xffff;
+
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret;
+}
+
+static int ad5764_chan_info_to_reg(struct iio_chan_spec const *chan, long info)
+{
+	switch (info) {
+	case 0:
+		return AD5764_REG_DATA(chan->address);
+	case IIO_CHAN_INFO_CALIBBIAS:
+		return AD5764_REG_OFFSET(chan->address);
+	case IIO_CHAN_INFO_CALIBSCALE:
+		return AD5764_REG_FINE_GAIN(chan->address);
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static int ad5764_write_raw(struct iio_dev *indio_dev,
+	struct iio_chan_spec const *chan, int val, int val2, long info)
+{
+	const int max_val = (1 << chan->scan_type.realbits);
+	unsigned int reg;
+
+	switch (info) {
+	case 0:
+		if (val >= max_val || val < 0)
+			return -EINVAL;
+		val <<= chan->scan_type.shift;
+		break;
+	case IIO_CHAN_INFO_CALIBBIAS:
+		if (val >= 128 || val < -128)
+			return -EINVAL;
+		break;
+	case IIO_CHAN_INFO_CALIBSCALE:
+		if (val >= 32 || val < -32)
+			return -EINVAL;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	reg = ad5764_chan_info_to_reg(chan, info);
+	return ad5764_write(indio_dev, reg, (u16)val);
+}
+
+static int ad5764_get_channel_vref(struct ad5764_state *st,
+	unsigned int channel)
+{
+	if (st->chip_info->int_vref)
+		return st->chip_info->int_vref;
+	else
+		return regulator_get_voltage(st->vref_reg[channel / 2].consumer);
+}
+
+static int ad5764_read_raw(struct iio_dev *indio_dev,
+	struct iio_chan_spec const *chan, int *val, int *val2, long info)
+{
+	struct ad5764_state *st = iio_priv(indio_dev);
+	unsigned long scale_uv;
+	unsigned int reg;
+	int vref;
+	int ret;
+
+	switch (info) {
+	case 0:
+		reg = AD5764_REG_DATA(chan->address);
+		ret = ad5764_read(indio_dev, reg, val);
+		if (ret < 0)
+			return ret;
+		*val >>= chan->scan_type.shift;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_CALIBBIAS:
+		reg = AD5764_REG_OFFSET(chan->address);
+		ret = ad5764_read(indio_dev, reg, val);
+		if (ret < 0)
+			return ret;
+		*val = sign_extend32(*val, 7);
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_CALIBSCALE:
+		reg = AD5764_REG_FINE_GAIN(chan->address);
+		ret = ad5764_read(indio_dev, reg, val);
+		if (ret < 0)
+			return ret;
+		*val = sign_extend32(*val, 5);
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		/* vout = 4 * vref + ((dac_code / 65535) - 0.5) */
+		vref = ad5764_get_channel_vref(st, chan->channel);
+		if (vref < 0)
+			return vref;
+
+		scale_uv = (vref * 4 * 100) >> chan->scan_type.realbits;
+		*val = scale_uv / 100000;
+		*val2 = (scale_uv % 100000) * 10;
+		return IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_OFFSET:
+		*val = -(1 << chan->scan_type.realbits) / 2;
+		return IIO_VAL_INT;
+	}
+
+	return -EINVAL;
+}
+
+static const struct iio_info ad5764_info = {
+	.read_raw = ad5764_read_raw,
+	.write_raw = ad5764_write_raw,
+	.driver_module = THIS_MODULE,
+};
+
+static int __devinit ad5764_probe(struct spi_device *spi)
+{
+	enum ad5764_type type = spi_get_device_id(spi)->driver_data;
+	struct iio_dev *indio_dev;
+	struct ad5764_state *st;
+	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->spi = spi;
+	st->chip_info = &ad5764_chip_infos[type];
+
+	indio_dev->dev.parent = &spi->dev;
+	indio_dev->name = spi_get_device_id(spi)->name;
+	indio_dev->info = &ad5764_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->num_channels = AD5764_NUM_CHANNELS;
+	indio_dev->channels = st->chip_info->channels;
+
+	if (st->chip_info->int_vref == 0) {
+		st->vref_reg[0].supply = "vrefAB";
+		st->vref_reg[1].supply = "vrefCD";
+
+		ret = regulator_bulk_get(&st->spi->dev,
+			ARRAY_SIZE(st->vref_reg), st->vref_reg);
+		if (ret) {
+			dev_err(&spi->dev, "Failed to request vref regulators: %d\n",
+				ret);
+			goto error_free;
+		}
+
+		ret = regulator_bulk_enable(ARRAY_SIZE(st->vref_reg),
+			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:
+	if (st->chip_info->int_vref == 0)
+		regulator_bulk_disable(ARRAY_SIZE(st->vref_reg), st->vref_reg);
+error_free_reg:
+	if (st->chip_info->int_vref == 0)
+		regulator_bulk_free(ARRAY_SIZE(st->vref_reg), st->vref_reg);
+error_free:
+	iio_free_device(indio_dev);
+
+	return ret;
+}
+
+static int __devexit ad5764_remove(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev = spi_get_drvdata(spi);
+	struct ad5764_state *st = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+
+	if (st->chip_info->int_vref == 0) {
+		regulator_bulk_disable(ARRAY_SIZE(st->vref_reg), st->vref_reg);
+		regulator_bulk_free(ARRAY_SIZE(st->vref_reg), st->vref_reg);
+	}
+
+	iio_free_device(indio_dev);
+
+	return 0;
+}
+
+static const struct spi_device_id ad5764_ids[] = {
+	{ "ad5744", ID_AD5744 },
+	{ "ad5744r", ID_AD5744R },
+	{ "ad5764", ID_AD5764 },
+	{ "ad5764r", ID_AD5764R },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, ad5764_ids);
+
+static struct spi_driver ad5764_driver = {
+	.driver = {
+		.name = "ad5764",
+		.owner = THIS_MODULE,
+	},
+	.probe = ad5764_probe,
+	.remove = __devexit_p(ad5764_remove),
+	.id_table = ad5764_ids,
+};
+
+static int __init ad5764_spi_init(void)
+{
+	return spi_register_driver(&ad5764_driver);
+}
+module_init(ad5764_spi_init);
+
+static void __exit ad5764_spi_exit(void)
+{
+	spi_unregister_driver(&ad5764_driver);
+}
+module_exit(ad5764_spi_exit);
+
+MODULE_AUTHOR("Lars-Peter Clausen <[e-mail]>");
+MODULE_DESCRIPTION("Analog Devices AD5744/AD5744R/AD5764/AD5764R DAC");
+MODULE_LICENSE("GPL v2");