iio: accel: Add driver for the mCube MC3230 3-axis accelerometer

Add an IIO driver for the mCube MC3230 3-axis accelerometer.

A datasheet for the mCube MC3230 can be found here:
http://www.mcubemems.com/wp-content/uploads/2014/10/MC3230_2-Datasheet-APS-048-0007v1.6.pdf

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

3 files changed, 222 insertions, 0 deletions

diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
index a8e9ed47bbb4..2b791fe1e2bc 100644
--- a/drivers/iio/accel/Kconfig
+++ b/drivers/iio/accel/Kconfig
@@ -161,6 +161,16 @@ config KXCJK1013
           To compile this driver as a module, choose M here: the module will
           be called kxcjk-1013.
 
+config MC3230
+        tristate "mCube MC3230 Digital Accelerometer Driver"
+        depends on I2C
+        help
+          Say yes here to build support for the mCube MC3230 low-g tri-axial
+          digital accelerometer.
+
+          To compile this driver as a module, choose M here: the
+          module will be called mc3230.
+
 config MMA7455
         tristate
         select IIO_BUFFER
diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
index b5c2a0b5550f..f5d3ddee619e 100644
--- a/drivers/iio/accel/Makefile
+++ b/drivers/iio/accel/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_KXCJK1013) += kxcjk-1013.o
 obj-$(CONFIG_KXSD9)     += kxsd9.o
 obj-$(CONFIG_KXSD9_SPI) += kxsd9-spi.o
 obj-$(CONFIG_KXSD9_I2C) += kxsd9-i2c.o
+obj-$(CONFIG_MC3230)    += mc3230.o
 
 obj-$(CONFIG_MMA7455)           += mma7455_core.o
 obj-$(CONFIG_MMA7455_I2C)       += mma7455_i2c.o
diff --git a/drivers/iio/accel/mc3230.c b/drivers/iio/accel/mc3230.c
new file mode 100644
index 000000000000..4ea2ff623a6d
--- /dev/null
+++ b/drivers/iio/accel/mc3230.c
@@ -0,0 +1,211 @@
+/**
+ * mCube MC3230 3-Axis Accelerometer
+ *
+ * Copyright (c) 2016 Hans de Goede <hdegoede@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * IIO driver for mCube MC3230; 7-bit I2C address: 0x4c.
+ */
+
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define MC3230_REG_XOUT                 0x00
+#define MC3230_REG_YOUT                 0x01
+#define MC3230_REG_ZOUT                 0x02
+
+#define MC3230_REG_MODE                 0x07
+#define MC3230_MODE_OPCON_MASK          0x03
+#define MC3230_MODE_OPCON_WAKE          0x01
+#define MC3230_MODE_OPCON_STANDBY       0x03
+
+#define MC3230_REG_CHIP_ID              0x18
+#define MC3230_CHIP_ID                  0x01
+
+#define MC3230_REG_PRODUCT_CODE         0x3b
+#define MC3230_PRODUCT_CODE             0x19
+
+/*
+ * The accelerometer has one measurement range:
+ *
+ * -1.5g - +1.5g (8-bit, signed)
+ *
+ * scale = (1.5 + 1.5) * 9.81 / (2^8 - 1)       = 0.115411765
+ */
+
+static const int mc3230_nscale = 115411765;
+
+#define MC3230_CHANNEL(reg, axis) {     \
+        .type = IIO_ACCEL,      \
+        .address = reg, \
+        .modified = 1,  \
+        .channel2 = IIO_MOD_##axis,     \
+        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
+        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
+}
+
+static const struct iio_chan_spec mc3230_channels[] = {
+        MC3230_CHANNEL(MC3230_REG_XOUT, X),
+        MC3230_CHANNEL(MC3230_REG_YOUT, Y),
+        MC3230_CHANNEL(MC3230_REG_ZOUT, Z),
+};
+
+struct mc3230_data {
+        struct i2c_client *client;
+};
+
+static int mc3230_set_opcon(struct mc3230_data *data, int opcon)
+{
+        int ret;
+        struct i2c_client *client = data->client;
+
+        ret = i2c_smbus_read_byte_data(client, MC3230_REG_MODE);
+        if (ret < 0) {
+                dev_err(&client->dev, "failed to read mode reg: %d\n", ret);
+                return ret;
+        }
+
+        ret &= ~MC3230_MODE_OPCON_MASK;
+        ret |= opcon;
+
+        ret = i2c_smbus_write_byte_data(client, MC3230_REG_MODE, ret);
+        if (ret < 0) {
+                dev_err(&client->dev, "failed to write mode reg: %d\n", ret);
+                return ret;
+        }
+
+        return 0;
+}
+
+static int mc3230_read_raw(struct iio_dev *indio_dev,
+                                struct iio_chan_spec const *chan,
+                                int *val, int *val2, long mask)
+{
+        struct mc3230_data *data = iio_priv(indio_dev);
+        int ret;
+
+        switch (mask) {
+        case IIO_CHAN_INFO_RAW:
+                ret = i2c_smbus_read_byte_data(data->client, chan->address);
+                if (ret < 0)
+                        return ret;
+                *val = sign_extend32(ret, 7);
+                return IIO_VAL_INT;
+        case IIO_CHAN_INFO_SCALE:
+                *val = 0;
+                *val2 = mc3230_nscale;
+                return IIO_VAL_INT_PLUS_NANO;
+        default:
+                return -EINVAL;
+        }
+}
+
+static const struct iio_info mc3230_info = {
+        .driver_module  = THIS_MODULE,
+        .read_raw       = mc3230_read_raw,
+};
+
+static int mc3230_probe(struct i2c_client *client,
+                        const struct i2c_device_id *id)
+{
+        int ret;
+        struct iio_dev *indio_dev;
+        struct mc3230_data *data;
+
+        /* First check chip-id and product-id */
+        ret = i2c_smbus_read_byte_data(client, MC3230_REG_CHIP_ID);
+        if (ret != MC3230_CHIP_ID)
+                return (ret < 0) ? ret : -ENODEV;
+
+        ret = i2c_smbus_read_byte_data(client, MC3230_REG_PRODUCT_CODE);
+        if (ret != MC3230_PRODUCT_CODE)
+                return (ret < 0) ? ret : -ENODEV;
+
+        indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+        if (!indio_dev) {
+                dev_err(&client->dev, "iio allocation failed!\n");
+                return -ENOMEM;
+        }
+
+        data = iio_priv(indio_dev);
+        data->client = client;
+        i2c_set_clientdata(client, indio_dev);
+
+        indio_dev->dev.parent = &client->dev;
+        indio_dev->info = &mc3230_info;
+        indio_dev->name = "mc3230";
+        indio_dev->modes = INDIO_DIRECT_MODE;
+        indio_dev->channels = mc3230_channels;
+        indio_dev->num_channels = ARRAY_SIZE(mc3230_channels);
+
+        ret = mc3230_set_opcon(data, MC3230_MODE_OPCON_WAKE);
+        if (ret < 0)
+                return ret;
+
+        ret = iio_device_register(indio_dev);
+        if (ret < 0) {
+                dev_err(&client->dev, "device_register failed\n");
+                mc3230_set_opcon(data, MC3230_MODE_OPCON_STANDBY);
+        }
+
+        return ret;
+}
+
+static int mc3230_remove(struct i2c_client *client)
+{
+        struct iio_dev *indio_dev = i2c_get_clientdata(client);
+
+        iio_device_unregister(indio_dev);
+
+        return mc3230_set_opcon(iio_priv(indio_dev), MC3230_MODE_OPCON_STANDBY);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int mc3230_suspend(struct device *dev)
+{
+        struct mc3230_data *data;
+
+        data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
+
+        return mc3230_set_opcon(data, MC3230_MODE_OPCON_STANDBY);
+}
+
+static int mc3230_resume(struct device *dev)
+{
+        struct mc3230_data *data;
+
+        data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
+
+        return mc3230_set_opcon(data, MC3230_MODE_OPCON_WAKE);
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(mc3230_pm_ops, mc3230_suspend, mc3230_resume);
+
+static const struct i2c_device_id mc3230_i2c_id[] = {
+        {"mc3230", 0},
+        {}
+};
+MODULE_DEVICE_TABLE(i2c, mc3230_i2c_id);
+
+static struct i2c_driver mc3230_driver = {
+        .driver = {
+                .name = "mc3230",
+                .pm = &mc3230_pm_ops,
+        },
+        .probe          = mc3230_probe,
+        .remove         = mc3230_remove,
+        .id_table       = mc3230_i2c_id,
+};
+
+module_i2c_driver(mc3230_driver);
+
+MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
+MODULE_DESCRIPTION("mCube MC3230 3-Axis Accelerometer driver");
+MODULE_LICENSE("GPL v2");