This patch add support for Domintech DMARD06 accelerometer.

Domintech DMARD06 is a low-g tri-axial digital accelerometer for
cost-sensitive consumer application.

Signed-off-by: Aleksei Mamlin <mamli...@gmail.com>
---
 .../devicetree/bindings/iio/accel/dmard06.txt      |  17 ++
 drivers/iio/accel/Kconfig                          |  11 ++
 drivers/iio/accel/Makefile                         |   1 +
 drivers/iio/accel/dmard06.c                        | 219 +++++++++++++++++++++
 4 files changed, 248 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/accel/dmard06.txt
 create mode 100644 drivers/iio/accel/dmard06.c

diff --git a/Documentation/devicetree/bindings/iio/accel/dmard06.txt 
b/Documentation/devicetree/bindings/iio/accel/dmard06.txt
new file mode 100644
index 0000000..cc2231a
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/accel/dmard06.txt
@@ -0,0 +1,17 @@
+Device tree bindings for Domintech DMARD06 acceletometer
+
+Required properties:
+ - compatible          : Should be "domintech,dmard06"
+ - reg                 : I2C address of the chip. Should be 0x1c
+
+Example:
+       &i2c1 {
+               /* ... */
+
+               accelerometer@1c {
+                       compatible = "domintech,dmard06";
+                       reg = <0x1c>;
+               };
+
+               /* ... */
+       };
diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
index e4a758c..abc8536 100644
--- a/drivers/iio/accel/Kconfig
+++ b/drivers/iio/accel/Kconfig
@@ -40,6 +40,17 @@ config BMC150_ACCEL_SPI
        tristate
        select REGMAP_SPI
 
+config DMARD06
+       tristate "Domintech DMARD06 Digital Accelerometer Driver"
+       depends on OF || COMPILE_TEST
+       depends on I2C
+       help
+         Say yes here to build support for the Domintech DMARD06 low-g
+         tri-axial digital accelerometer connected via an I2C bus.
+
+         To compile this driver as a module, choose M here: the
+         module will be called dmard06.
+
 config HID_SENSOR_ACCEL_3D
        depends on HID_SENSOR_HUB
        select IIO_BUFFER
diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
index 71b6794..a96b269 100644
--- a/drivers/iio/accel/Makefile
+++ b/drivers/iio/accel/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_BMA180) += bma180.o
 obj-$(CONFIG_BMC150_ACCEL) += bmc150-accel-core.o
 obj-$(CONFIG_BMC150_ACCEL_I2C) += bmc150-accel-i2c.o
 obj-$(CONFIG_BMC150_ACCEL_SPI) += bmc150-accel-spi.o
+obj-$(CONFIG_DMARD06)  += dmard06.o
 obj-$(CONFIG_HID_SENSOR_ACCEL_3D) += hid-sensor-accel-3d.o
 obj-$(CONFIG_KXCJK1013) += kxcjk-1013.o
 obj-$(CONFIG_KXSD9)    += kxsd9.o
diff --git a/drivers/iio/accel/dmard06.c b/drivers/iio/accel/dmard06.c
new file mode 100644
index 0000000..433e430
--- /dev/null
+++ b/drivers/iio/accel/dmard06.c
@@ -0,0 +1,219 @@
+/*
+ * IIO driver for Domintech DMARD06 accelerometer
+ *
+ * Copyright (C) 2016 Aleksei Mamlin <mamli...@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+
+struct dmard06_data {
+       struct i2c_client *client;
+};
+
+#define DMARD06_DRV_NAME               "dmard06"
+
+/* Device data registers */
+#define DMARD06_CHIP_ID_REG            0x0f
+#define DMARD06_TOUT_REG               0x40
+#define DMARD06_XOUT_REG               0x41
+#define DMARD06_YOUT_REG               0x42
+#define DMARD06_ZOUT_REG               0x43
+
+/* Device ID value */
+#define DMARD06_CHIP_ID                        0x06
+
+/* Device values */
+#define DMARD06_AXIS_MAX_VAL           64
+#define DMARD06_AXIS_SCALE_VAL         31250
+#define DMARD06_TEMP_CENTER_VAL                25
+
+static int dmard06_i2c_read(struct i2c_client *client, u8 reg, u8 *buf)
+{
+       int error;
+
+       error = i2c_master_send(client, &reg, 1);
+       if (unlikely(error < 0))
+               return error;
+
+       error = i2c_master_recv(client, buf, 1);
+       if (unlikely(error < 0))
+               return error;
+       return 0;
+}
+
+static int dmard06_read_chip_id(struct dmard06_data *dmard06)
+{
+       u8 buf;
+       u8 chip_id;
+       int error;
+
+       error = dmard06_i2c_read(dmard06->client, DMARD06_CHIP_ID_REG, &buf);
+       if (error) {
+               dev_err(&dmard06->client->dev, "Failed to read chip id: %d\n",
+                       error);
+               return error;
+       }
+
+       chip_id = (buf & 0x00ff);
+       if (chip_id != DMARD06_CHIP_ID) {
+               dev_err(&dmard06->client->dev, "Invalid chip id: %02x\n",
+                       chip_id);
+               return -EINVAL;
+       }
+
+       dev_info(&dmard06->client->dev, "Found DMARD%02x chip\n", chip_id);
+
+       return 0;
+}
+
+static int dmard06_read_raw(struct iio_dev *indio_dev,
+                           struct iio_chan_spec const *chan,
+                           int *val, int *val2, long mask)
+{
+       struct dmard06_data *dmard06 = iio_priv(indio_dev);
+       u8 buf;
+       bool reversed;
+       int error;
+       int tmp;
+
+       switch (mask) {
+       case IIO_CHAN_INFO_RAW:
+               error = dmard06_i2c_read(dmard06->client, chan->address, &buf);
+               if (error) {
+                       dev_err(&dmard06->client->dev,
+                               "Failed to read data %d\n", error);
+                       return error;
+               }
+
+               reversed = (buf >> 7) & 1;
+               tmp = (int)((buf & 0x7f) >> 1);
+
+               switch (chan->type) {
+               case IIO_ACCEL:
+                       *val = reversed ? (tmp - DMARD06_AXIS_MAX_VAL) : tmp;
+                       return IIO_VAL_INT;
+               case IIO_TEMP:
+                       *val = reversed ? -tmp : tmp;
+                       return IIO_VAL_INT;
+               default:
+                       return -EINVAL;
+               }
+       case IIO_CHAN_INFO_OFFSET:
+               switch (chan->type) {
+               case IIO_TEMP:
+                       *val = DMARD06_TEMP_CENTER_VAL;
+                       return IIO_VAL_INT;
+               default:
+                       return -EINVAL;
+               }
+       case IIO_CHAN_INFO_SCALE:
+               switch (chan->type) {
+               case IIO_ACCEL:
+                       *val = 0;
+                       *val2 = DMARD06_AXIS_SCALE_VAL;
+                       return IIO_VAL_INT_PLUS_MICRO;
+               default:
+                       return -EINVAL;
+               }
+       default:
+               return -EINVAL;
+       }
+}
+
+static const struct iio_info dmard06_info = {
+       .driver_module  = THIS_MODULE,
+       .read_raw       = dmard06_read_raw,
+};
+
+#define DMARD06_ACCEL_CHANNEL(_axis, reg) {                    \
+       .type = IIO_ACCEL,                                      \
+       .address = reg,                                         \
+       .channel2 = IIO_MOD_##_axis,                            \
+       .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
+       .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
+       .modified = 1,                                          \
+}
+
+#define DMARD06_TEMP_CHANNEL(reg) {                            \
+       .type = IIO_TEMP,                                       \
+       .address = reg,                                         \
+       .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |          \
+                             BIT(IIO_CHAN_INFO_OFFSET),        \
+}
+
+static const struct iio_chan_spec dmard06_channels[] = {
+       DMARD06_ACCEL_CHANNEL(X, DMARD06_XOUT_REG),
+       DMARD06_ACCEL_CHANNEL(Y, DMARD06_YOUT_REG),
+       DMARD06_ACCEL_CHANNEL(Z, DMARD06_ZOUT_REG),
+       DMARD06_TEMP_CHANNEL(DMARD06_TOUT_REG),
+};
+
+static int dmard06_probe(struct i2c_client *client,
+                       const struct i2c_device_id *id)
+{
+       int error;
+       struct iio_dev *indio_dev;
+       struct dmard06_data *dmard06;
+
+       dev_dbg(&client->dev, "I2C Address: 0x%02x\n", client->addr);
+
+       if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+               dev_err(&client->dev, "I2C check functionality failed\n");
+               return -ENXIO;
+       }
+
+       indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*dmard06));
+       if (!indio_dev) {
+               dev_err(&client->dev, "Failed to allocate iio device\n");
+               return -ENOMEM;
+       }
+
+       dmard06 = iio_priv(indio_dev);
+       dmard06->client = client;
+
+       error = dmard06_read_chip_id(dmard06);
+       if (error)
+               return error;
+
+       i2c_set_clientdata(client, indio_dev);
+       indio_dev->dev.parent = &client->dev;
+       indio_dev->name = DMARD06_DRV_NAME;
+       indio_dev->modes = INDIO_DIRECT_MODE;
+       indio_dev->channels = dmard06_channels;
+       indio_dev->num_channels = ARRAY_SIZE(dmard06_channels);
+       indio_dev->info = &dmard06_info;
+
+       return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id dmard06_id[] = {
+       { "dmard06", 0 },
+       { }
+};
+MODULE_DEVICE_TABLE(i2c, dmard06_id);
+
+static const struct of_device_id dmard06_of_match[] = {
+       { .compatible = "domintech,dmard06" },
+       { }
+};
+MODULE_DEVICE_TABLE(of, dmard06_of_match);
+
+static struct i2c_driver dmard06_driver = {
+       .probe = dmard06_probe,
+       .id_table = dmard06_id,
+       .driver = {
+               .name = DMARD06_DRV_NAME,
+               .of_match_table = of_match_ptr(dmard06_of_match),
+       },
+};
+module_i2c_driver(dmard06_driver);
+
+MODULE_AUTHOR("Aleksei Mamlin <mamli...@gmail.com>");
+MODULE_DESCRIPTION("Domintech DMARD06 accelerometer driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.3

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