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;