iio: add support of the max5821

Signed-off-by: Philippe Reynes <tremyfr@yahoo.fr>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

3 files changed, 414 insertions, 0 deletions

diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
index f278eff42a4c..2236ea22f98a 100644
--- a/drivers/iio/dac/Kconfig
+++ b/drivers/iio/dac/Kconfig
@@ -152,6 +152,14 @@ config MAX517
           This driver can also be built as a module.  If so, the module
           will be called max517.
 
+config MAX5821
+        tristate "Maxim MAX5821 DAC driver"
+        depends on I2C
+        depends on OF
+        help
+          Say yes here to build support for Maxim MAX5821
+          10 bits DAC.
+
 config MCP4725
         tristate "MCP4725 DAC driver"
         depends on I2C
diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
index 10107640bb46..52be7e1acf16 100644
--- a/drivers/iio/dac/Makefile
+++ b/drivers/iio/dac/Makefile
@@ -17,5 +17,6 @@ obj-$(CONFIG_AD5791) += ad5791.o
 obj-$(CONFIG_AD5686) += ad5686.o
 obj-$(CONFIG_AD7303) += ad7303.o
 obj-$(CONFIG_MAX517) += max517.o
+obj-$(CONFIG_MAX5821) += max5821.o
 obj-$(CONFIG_MCP4725) += mcp4725.o
 obj-$(CONFIG_MCP4922) += mcp4922.o
diff --git a/drivers/iio/dac/max5821.c b/drivers/iio/dac/max5821.c
new file mode 100644
index 000000000000..6e914495b346
--- /dev/null
+++ b/drivers/iio/dac/max5821.c
@@ -0,0 +1,405 @@
+ /*
+  * iio/dac/max5821.c
+  * Copyright (C) 2014 Philippe Reynes
+  *
+  * This program is free software; you can redistribute it and/or modify
+  * it under the terms of the GNU General Public License version 2 as
+  * published by the Free Software Foundation.
+  */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/regulator/consumer.h>
+
+#define MAX5821_MAX_DAC_CHANNELS                2
+
+/* command bytes */
+#define MAX5821_LOAD_DAC_A_IN_REG_B             0x00
+#define MAX5821_LOAD_DAC_B_IN_REG_A             0x10
+#define MAX5821_EXTENDED_COMMAND_MODE           0xf0
+#define MAX5821_READ_DAC_A_COMMAND              0xf1
+#define MAX5821_READ_DAC_B_COMMAND              0xf2
+
+#define MAX5821_EXTENDED_POWER_UP               0x00
+#define MAX5821_EXTENDED_POWER_DOWN_MODE0       0x01
+#define MAX5821_EXTENDED_POWER_DOWN_MODE1       0x02
+#define MAX5821_EXTENDED_POWER_DOWN_MODE2       0x03
+#define MAX5821_EXTENDED_DAC_A                  0x04
+#define MAX5821_EXTENDED_DAC_B                  0x08
+
+enum max5821_device_ids {
+        ID_MAX5821,
+};
+
+struct max5821_data {
+        struct i2c_client       *client;
+        struct regulator        *vref_reg;
+        unsigned short          vref_mv;
+        bool                    powerdown[MAX5821_MAX_DAC_CHANNELS];
+        u8                      powerdown_mode[MAX5821_MAX_DAC_CHANNELS];
+        struct mutex            lock;
+};
+
+static const char * const max5821_powerdown_modes[] = {
+        "three_state",
+        "1kohm_to_gnd",
+        "100kohm_to_gnd",
+};
+
+enum {
+        MAX5821_THREE_STATE,
+        MAX5821_1KOHM_TO_GND,
+        MAX5821_100KOHM_TO_GND
+};
+
+static int max5821_get_powerdown_mode(struct iio_dev *indio_dev,
+                                      const struct iio_chan_spec *chan)
+{
+        struct max5821_data *st = iio_priv(indio_dev);
+
+        return st->powerdown_mode[chan->channel];
+}
+
+static int max5821_set_powerdown_mode(struct iio_dev *indio_dev,
+                                      const struct iio_chan_spec *chan,
+                                      unsigned int mode)
+{
+        struct max5821_data *st = iio_priv(indio_dev);
+
+        st->powerdown_mode[chan->channel] = mode;
+
+        return 0;
+}
+
+static const struct iio_enum max5821_powerdown_mode_enum = {
+        .items = max5821_powerdown_modes,
+        .num_items = ARRAY_SIZE(max5821_powerdown_modes),
+        .get = max5821_get_powerdown_mode,
+        .set = max5821_set_powerdown_mode,
+};
+
+static ssize_t max5821_read_dac_powerdown(struct iio_dev *indio_dev,
+                                          uintptr_t private,
+                                          const struct iio_chan_spec *chan,
+                                          char *buf)
+{
+        struct max5821_data *st = iio_priv(indio_dev);
+
+        return sprintf(buf, "%d\n", st->powerdown[chan->channel]);
+}
+
+static int max5821_sync_powerdown_mode(struct max5821_data *data,
+                                       const struct iio_chan_spec *chan)
+{
+        u8 outbuf[2];
+
+        outbuf[0] = MAX5821_EXTENDED_COMMAND_MODE;
+
+        if (chan->channel == 0)
+                outbuf[1] = MAX5821_EXTENDED_DAC_A;
+        else
+                outbuf[1] = MAX5821_EXTENDED_DAC_B;
+
+        if (data->powerdown[chan->channel])
+                outbuf[1] |= data->powerdown_mode[chan->channel] + 1;
+        else
+                outbuf[1] |= MAX5821_EXTENDED_POWER_UP;
+
+        return i2c_master_send(data->client, outbuf, 2);
+}
+
+static ssize_t max5821_write_dac_powerdown(struct iio_dev *indio_dev,
+                                           uintptr_t private,
+                                           const struct iio_chan_spec *chan,
+                                           const char *buf, size_t len)
+{
+        struct max5821_data *data = iio_priv(indio_dev);
+        bool powerdown;
+        int ret;
+
+        ret = strtobool(buf, &powerdown);
+        if (ret)
+                return ret;
+
+        data->powerdown[chan->channel] = powerdown;
+
+        ret = max5821_sync_powerdown_mode(data, chan);
+        if (ret < 0)
+                return ret;
+
+        return len;
+}
+
+static const struct iio_chan_spec_ext_info max5821_ext_info[] = {
+        {
+                .name = "powerdown",
+                .read = max5821_read_dac_powerdown,
+                .write = max5821_write_dac_powerdown,
+                .shared = IIO_SEPARATE,
+        },
+        IIO_ENUM("powerdown_mode", IIO_SEPARATE, &max5821_powerdown_mode_enum),
+        IIO_ENUM_AVAILABLE("powerdown_mode", &max5821_powerdown_mode_enum),
+        { },
+};
+
+#define MAX5821_CHANNEL(chan) {                                 \
+        .type = IIO_VOLTAGE,                                    \
+        .indexed = 1,                                           \
+        .output = 1,                                            \
+        .channel = (chan),                                      \
+        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
+        .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE),    \
+        .ext_info = max5821_ext_info,                           \
+}
+
+static const struct iio_chan_spec max5821_channels[] = {
+        MAX5821_CHANNEL(0),
+        MAX5821_CHANNEL(1)
+};
+
+static const u8 max5821_read_dac_command[] = {
+        MAX5821_READ_DAC_A_COMMAND,
+        MAX5821_READ_DAC_B_COMMAND
+};
+
+static const u8 max5821_load_dac_command[] = {
+        MAX5821_LOAD_DAC_A_IN_REG_B,
+        MAX5821_LOAD_DAC_B_IN_REG_A
+};
+
+static int max5821_get_value(struct iio_dev *indio_dev,
+                             int *val, int channel)
+{
+        struct max5821_data *data = iio_priv(indio_dev);
+        struct i2c_client *client = data->client;
+        u8 outbuf[1];
+        u8 inbuf[2];
+        int ret;
+
+        if ((channel != 0) && (channel != 1))
+                return -EINVAL;
+
+        outbuf[0] = max5821_read_dac_command[channel];
+
+        mutex_lock(&data->lock);
+
+        ret = i2c_master_send(client, outbuf, 1);
+        if (ret < 0) {
+                mutex_unlock(&data->lock);
+                return ret;
+        } else if (ret != 1) {
+                mutex_unlock(&data->lock);
+                return -EIO;
+        }
+
+        ret = i2c_master_recv(client, inbuf, 2);
+        if (ret < 0) {
+                mutex_unlock(&data->lock);
+                return ret;
+        } else if (ret != 2) {
+                mutex_unlock(&data->lock);
+                return -EIO;
+        }
+
+        mutex_unlock(&data->lock);
+
+        *val = ((inbuf[0] & 0x0f) << 6) | (inbuf[1] >> 2);
+
+        return IIO_VAL_INT;
+}
+
+static int max5821_set_value(struct iio_dev *indio_dev,
+                             int val, int channel)
+{
+        struct max5821_data *data = iio_priv(indio_dev);
+        struct i2c_client *client = data->client;
+        u8 outbuf[2];
+        int ret;
+
+        if ((val < 0) || (val > 1023))
+                return -EINVAL;
+
+        if ((channel != 0) && (channel != 1))
+                return -EINVAL;
+
+        outbuf[0] = max5821_load_dac_command[channel];
+        outbuf[0] |= val >> 6;
+        outbuf[1] = (val & 0x3f) << 2;
+
+        ret = i2c_master_send(client, outbuf, 2);
+        if (ret < 0)
+                return ret;
+        else if (ret != 2)
+                return -EIO;
+        else
+                return 0;
+}
+
+static int max5821_read_raw(struct iio_dev *indio_dev,
+                           struct iio_chan_spec const *chan,
+                           int *val, int *val2, long mask)
+{
+        struct max5821_data *data = iio_priv(indio_dev);
+
+        switch (mask) {
+        case IIO_CHAN_INFO_RAW:
+                return max5821_get_value(indio_dev, val, chan->channel);
+        case IIO_CHAN_INFO_SCALE:
+                *val = data->vref_mv;
+                *val2 = 10;
+                return IIO_VAL_FRACTIONAL_LOG2;
+        default:
+                return -EINVAL;
+        }
+}
+
+static int max5821_write_raw(struct iio_dev *indio_dev,
+                             struct iio_chan_spec const *chan,
+                             int val, int val2, long mask)
+{
+        if (val2 != 0)
+                return -EINVAL;
+
+        switch (mask) {
+        case IIO_CHAN_INFO_RAW:
+                return max5821_set_value(indio_dev, val, chan->channel);
+        default:
+                return -EINVAL;
+        }
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int max5821_suspend(struct device *dev)
+{
+        u8 outbuf[2] = { MAX5821_EXTENDED_COMMAND_MODE,
+                         MAX5821_EXTENDED_DAC_A |
+                         MAX5821_EXTENDED_DAC_B |
+                         MAX5821_EXTENDED_POWER_DOWN_MODE2 };
+
+        return i2c_master_send(to_i2c_client(dev), outbuf, 2);
+}
+
+static int max5821_resume(struct device *dev)
+{
+        u8 outbuf[2] = { MAX5821_EXTENDED_COMMAND_MODE,
+                         MAX5821_EXTENDED_DAC_A |
+                         MAX5821_EXTENDED_DAC_B |
+                         MAX5821_EXTENDED_POWER_UP };
+
+        return i2c_master_send(to_i2c_client(dev), outbuf, 2);
+}
+
+static SIMPLE_DEV_PM_OPS(max5821_pm_ops, max5821_suspend, max5821_resume);
+#define MAX5821_PM_OPS (&max5821_pm_ops)
+#else
+#define MAX5821_PM_OPS NULL
+#endif /* CONFIG_PM_SLEEP */
+
+static const struct iio_info max5821_info = {
+        .read_raw = max5821_read_raw,
+        .write_raw = max5821_write_raw,
+        .driver_module = THIS_MODULE,
+};
+
+static int max5821_probe(struct i2c_client *client,
+                        const struct i2c_device_id *id)
+{
+        struct max5821_data *data;
+        struct iio_dev *indio_dev;
+        u32 tmp;
+        int ret;
+
+        indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+        if (!indio_dev)
+                return -ENOMEM;
+        data = iio_priv(indio_dev);
+        i2c_set_clientdata(client, indio_dev);
+        data->client = client;
+        mutex_init(&data->lock);
+
+        /* max5821 start in powerdown mode 100Kohm to ground */
+        for (tmp = 0; tmp < MAX5821_MAX_DAC_CHANNELS; tmp++) {
+                data->powerdown[tmp] = true;
+                data->powerdown_mode[tmp] = MAX5821_100KOHM_TO_GND;
+        }
+
+        data->vref_reg = devm_regulator_get(&client->dev, "vref");
+        if (IS_ERR(data->vref_reg)) {
+                ret = PTR_ERR(data->vref_reg);
+                dev_err(&client->dev,
+                        "Failed to get vref regulator: %d\n", ret);
+                goto error_free_reg;
+        }
+
+        ret = regulator_enable(data->vref_reg);
+        if (ret) {
+                dev_err(&client->dev,
+                        "Failed to enable vref regulator: %d\n", ret);
+                goto error_free_reg;
+        }
+
+        ret = regulator_get_voltage(data->vref_reg);
+        if (ret < 0) {
+                dev_err(&client->dev,
+                        "Failed to get voltage on regulator: %d\n", ret);
+                goto error_disable_reg;
+        }
+
+        data->vref_mv = ret / 1000;
+
+        indio_dev->name = id->name;
+        indio_dev->dev.parent = &client->dev;
+        indio_dev->num_channels = ARRAY_SIZE(max5821_channels);
+        indio_dev->channels = max5821_channels;
+        indio_dev->modes = INDIO_DIRECT_MODE;
+        indio_dev->info = &max5821_info;
+
+        return iio_device_register(indio_dev);
+
+error_disable_reg:
+        regulator_disable(data->vref_reg);
+
+error_free_reg:
+
+        return ret;
+}
+
+static int max5821_remove(struct i2c_client *client)
+{
+        struct iio_dev *indio_dev = i2c_get_clientdata(client);
+        struct max5821_data *data = iio_priv(indio_dev);
+
+        iio_device_unregister(indio_dev);
+        regulator_disable(data->vref_reg);
+
+        return 0;
+}
+
+static const struct i2c_device_id max5821_id[] = {
+        { "max5821", ID_MAX5821 },
+        { }
+};
+MODULE_DEVICE_TABLE(i2c, max5821_id);
+
+static const struct of_device_id max5821_of_match[] = {
+        { .compatible = "maxim,max5821" },
+        { }
+};
+
+static struct i2c_driver max5821_driver = {
+        .driver = {
+                .name   = "max5821",
+                .pm     = MAX5821_PM_OPS,
+                .owner  = THIS_MODULE,
+        },
+        .probe          = max5821_probe,
+        .remove         = max5821_remove,
+        .id_table       = max5821_id,
+};
+module_i2c_driver(max5821_driver);
+
+MODULE_AUTHOR("Philippe Reynes <tremyfr@yahoo.fr>");
+MODULE_DESCRIPTION("MAX5821 DAC");
+MODULE_LICENSE("GPL v2");