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 <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

4 files changed, 426 insertions, 0 deletions

diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
index b1c0ee5294ca..f68756e6dd62 100644
--- a/drivers/iio/dac/Kconfig
+++ b/drivers/iio/dac/Kconfig
@@ -67,6 +67,16 @@ config AD5446
           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
diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
index c0d333b23ba3..5b528ebb3343 100644
--- a/drivers/iio/dac/Makefile
+++ b/drivers/iio/dac/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_AD5624R_SPI) += ad5624r_spi.o
 obj-$(CONFIG_AD5064) += ad5064.o
 obj-$(CONFIG_AD5504) += ad5504.o
 obj-$(CONFIG_AD5446) += ad5446.o
+obj-$(CONFIG_AD5449) += ad5449.o
 obj-$(CONFIG_AD5755) += ad5755.o
 obj-$(CONFIG_AD5764) += ad5764.o
 obj-$(CONFIG_AD5791) += ad5791.o
diff --git a/drivers/iio/dac/ad5449.c b/drivers/iio/dac/ad5449.c
new file mode 100644
index 000000000000..5b43030fe6e3
--- /dev/null
+++ b/drivers/iio/dac/ad5449.c
@@ -0,0 +1,375 @@
+/*
+ * AD5415, AD5426, AD5429, AD5432, AD5439, AD5443, AD5449 Digital to Analog
+ * Converter driver.
+ *
+ * Copyright 2012 Analog Devices Inc.
+ *  Author: Lars-Peter Clausen <lars@metafoo.de>
+ *
+ * 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 <lars@metafoo.de>");
+MODULE_DESCRIPTION("Analog Devices AD5449 and similar DACs");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/platform_data/ad5449.h b/include/linux/platform_data/ad5449.h
new file mode 100644
index 000000000000..bd712bd4b94e
--- /dev/null
+++ b/include/linux/platform_data/ad5449.h
@@ -0,0 +1,40 @@
+/*
+ * AD5415, AD5426, AD5429, AD5432, AD5439, AD5443, AD5449 Digital to Analog
+ * Converter driver.
+ *
+ * Copyright 2012 Analog Devices Inc.
+ *  Author: Lars-Peter Clausen <lars@metafoo.de>
+ *
+ * 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