iio: accel: add support for mxc4005 accelerometer
authorTeodora Baluta <teodora.baluta@intel.com>
Thu, 20 Aug 2015 14:37:31 +0000 (17:37 +0300)
committerJonathan Cameron <jic23@kernel.org>
Mon, 31 Aug 2015 16:32:05 +0000 (17:32 +0100)
This patch adds support for Memsic MXC4005XC 3-axis accelerometer. The
current implementation is a minimal one as it adds raw readings for the
three axes and setting scale from userspace.

Signed-off-by: Teodora Baluta <teodora.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
drivers/iio/accel/Kconfig
drivers/iio/accel/Makefile
drivers/iio/accel/mxc4005.c [new file with mode: 0644]

index a59047d7657eb414999d1f9081d914073a645f19..69302bed28609f6bcfffd3cb971ccff742f4bede 100644 (file)
@@ -137,6 +137,17 @@ config MMA9553
          To compile this driver as a module, choose M here: the module
          will be called mma9553.
 
+config MXC4005
+       tristate "Memsic MXC4005XC 3-Axis Accelerometer Driver"
+       depends on I2C
+       select REGMAP_I2C
+       help
+         Say yes here to build support for the Memsic MXC4005XC 3-axis
+         accelerometer.
+
+         To compile this driver as a module, choose M. The module will be
+         called mxc4005.
+
 config STK8312
        tristate "Sensortek STK8312 3-Axis Accelerometer Driver"
        depends on I2C
index ebd2675b2a0230d6aa07a7be8bec36bfd9a379aa..020dda0ae508e7d5105af891f88e4b047938ba79 100644 (file)
@@ -14,6 +14,8 @@ obj-$(CONFIG_MMA9551_CORE)    += mma9551_core.o
 obj-$(CONFIG_MMA9551)          += mma9551.o
 obj-$(CONFIG_MMA9553)          += mma9553.o
 
+obj-$(CONFIG_MXC4005)          += mxc4005.o
+
 obj-$(CONFIG_STK8312)          += stk8312.o
 obj-$(CONFIG_STK8BA50)         += stk8ba50.o
 
diff --git a/drivers/iio/accel/mxc4005.c b/drivers/iio/accel/mxc4005.c
new file mode 100644 (file)
index 0000000..e15c1bd
--- /dev/null
@@ -0,0 +1,354 @@
+/*
+ * 3-axis accelerometer driver for MXC4005XC Memsic sensor
+ *
+ * Copyright (c) 2014, Intel Corporation.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/acpi.h>
+#include <linux/regmap.h>
+#include <linux/iio/sysfs.h>
+
+#define MXC4005_DRV_NAME               "mxc4005"
+#define MXC4005_REGMAP_NAME            "mxc4005_regmap"
+
+#define MXC4005_REG_XOUT_UPPER         0x03
+#define MXC4005_REG_XOUT_LOWER         0x04
+#define MXC4005_REG_YOUT_UPPER         0x05
+#define MXC4005_REG_YOUT_LOWER         0x06
+#define MXC4005_REG_ZOUT_UPPER         0x07
+#define MXC4005_REG_ZOUT_LOWER         0x08
+
+#define MXC4005_REG_CONTROL            0x0D
+#define MXC4005_REG_CONTROL_MASK_FSR   GENMASK(6, 5)
+#define MXC4005_CONTROL_FSR_SHIFT      5
+
+#define MXC4005_REG_DEVICE_ID          0x0E
+
+enum mxc4005_axis {
+       AXIS_X,
+       AXIS_Y,
+       AXIS_Z,
+};
+
+enum mxc4005_range {
+       MXC4005_RANGE_2G,
+       MXC4005_RANGE_4G,
+       MXC4005_RANGE_8G,
+};
+
+struct mxc4005_data {
+       struct device *dev;
+       struct mutex mutex;
+       struct regmap *regmap;
+};
+
+/*
+ * MXC4005 can operate in the following ranges:
+ * +/- 2G, 4G, 8G (the default +/-2G)
+ *
+ * (2 + 2) * 9.81 / (2^12 - 1) = 0.009582
+ * (4 + 4) * 9.81 / (2^12 - 1) = 0.019164
+ * (8 + 8) * 9.81 / (2^12 - 1) = 0.038329
+ */
+static const struct {
+       u8 range;
+       int scale;
+} mxc4005_scale_table[] = {
+       {MXC4005_RANGE_2G, 9582},
+       {MXC4005_RANGE_4G, 19164},
+       {MXC4005_RANGE_8G, 38329},
+};
+
+
+static IIO_CONST_ATTR(in_accel_scale_available, "0.009582 0.019164 0.038329");
+
+static struct attribute *mxc4005_attributes[] = {
+       &iio_const_attr_in_accel_scale_available.dev_attr.attr,
+       NULL,
+};
+
+static const struct attribute_group mxc4005_attrs_group = {
+       .attrs = mxc4005_attributes,
+};
+
+static bool mxc4005_is_readable_reg(struct device *dev, unsigned int reg)
+{
+       switch (reg) {
+       case MXC4005_REG_XOUT_UPPER:
+       case MXC4005_REG_XOUT_LOWER:
+       case MXC4005_REG_YOUT_UPPER:
+       case MXC4005_REG_YOUT_LOWER:
+       case MXC4005_REG_ZOUT_UPPER:
+       case MXC4005_REG_ZOUT_LOWER:
+       case MXC4005_REG_DEVICE_ID:
+       case MXC4005_REG_CONTROL:
+               return true;
+       default:
+               return false;
+       }
+}
+
+static bool mxc4005_is_writeable_reg(struct device *dev, unsigned int reg)
+{
+       switch (reg) {
+       case MXC4005_REG_CONTROL:
+               return true;
+       default:
+               return false;
+       }
+}
+
+static const struct regmap_config mxc4005_regmap_config = {
+       .name = MXC4005_REGMAP_NAME,
+
+       .reg_bits = 8,
+       .val_bits = 8,
+
+       .max_register = MXC4005_REG_DEVICE_ID,
+
+       .readable_reg = mxc4005_is_readable_reg,
+       .writeable_reg = mxc4005_is_writeable_reg,
+};
+
+static int mxc4005_read_axis(struct mxc4005_data *data,
+                            unsigned int addr)
+{
+       __be16 reg;
+       int ret;
+
+       ret = regmap_bulk_read(data->regmap, addr, (u8 *) &reg, sizeof(reg));
+       if (ret < 0) {
+               dev_err(data->dev, "failed to read reg %02x\n", addr);
+               return ret;
+       }
+
+       return be16_to_cpu(reg);
+}
+
+static int mxc4005_read_scale(struct mxc4005_data *data)
+{
+       unsigned int reg;
+       int ret;
+       int i;
+
+       ret = regmap_read(data->regmap, MXC4005_REG_CONTROL, &reg);
+       if (ret < 0) {
+               dev_err(data->dev, "failed to read reg_control\n");
+               return ret;
+       }
+
+       i = reg >> MXC4005_CONTROL_FSR_SHIFT;
+
+       if (i < 0 || i >= ARRAY_SIZE(mxc4005_scale_table))
+               return -EINVAL;
+
+       return mxc4005_scale_table[i].scale;
+}
+
+static int mxc4005_set_scale(struct mxc4005_data *data, int val)
+{
+       unsigned int reg;
+       int i;
+       int ret;
+
+       for (i = 0; i < ARRAY_SIZE(mxc4005_scale_table); i++) {
+               if (mxc4005_scale_table[i].scale == val) {
+                       reg = i << MXC4005_CONTROL_FSR_SHIFT;
+                       ret = regmap_update_bits(data->regmap,
+                                                MXC4005_REG_CONTROL,
+                                                MXC4005_REG_CONTROL_MASK_FSR,
+                                                reg);
+                       if (ret < 0)
+                               dev_err(data->dev,
+                                       "failed to write reg_control\n");
+                       return ret;
+               }
+       }
+
+       return -EINVAL;
+}
+
+static int mxc4005_read_raw(struct iio_dev *indio_dev,
+                           struct iio_chan_spec const *chan,
+                           int *val, int *val2, long mask)
+{
+       struct mxc4005_data *data = iio_priv(indio_dev);
+       int ret;
+
+       switch (mask) {
+       case IIO_CHAN_INFO_RAW:
+               switch (chan->type) {
+               case IIO_ACCEL:
+                       if (iio_buffer_enabled(indio_dev))
+                               return -EBUSY;
+
+                       ret = mxc4005_read_axis(data, chan->address);
+                       if (ret < 0)
+                               return ret;
+                       *val = sign_extend32(ret >> 4, 11);
+                       return IIO_VAL_INT;
+               default:
+                       return -EINVAL;
+               }
+       case IIO_CHAN_INFO_SCALE:
+               ret = mxc4005_read_scale(data);
+               if (ret < 0)
+                       return ret;
+
+               *val = 0;
+               *val2 = ret;
+               return IIO_VAL_INT_PLUS_MICRO;
+       default:
+               return -EINVAL;
+       }
+}
+
+static int mxc4005_write_raw(struct iio_dev *indio_dev,
+                            struct iio_chan_spec const *chan,
+                            int val, int val2, long mask)
+{
+       struct mxc4005_data *data = iio_priv(indio_dev);
+
+       switch (mask) {
+       case IIO_CHAN_INFO_SCALE:
+               if (val != 0)
+                       return -EINVAL;
+
+               return mxc4005_set_scale(data, val2);
+       default:
+               return -EINVAL;
+       }
+}
+
+static const struct iio_info mxc4005_info = {
+       .driver_module  = THIS_MODULE,
+       .read_raw       = mxc4005_read_raw,
+       .write_raw      = mxc4005_write_raw,
+       .attrs          = &mxc4005_attrs_group,
+};
+
+#define MXC4005_CHANNEL(_axis, _addr) {                                \
+       .type = IIO_ACCEL,                                      \
+       .modified = 1,                                          \
+       .channel2 = IIO_MOD_##_axis,                            \
+       .address = _addr,                                       \
+       .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
+       .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
+}
+
+static const struct iio_chan_spec mxc4005_channels[] = {
+       MXC4005_CHANNEL(X, MXC4005_REG_XOUT_UPPER),
+       MXC4005_CHANNEL(Y, MXC4005_REG_YOUT_UPPER),
+       MXC4005_CHANNEL(Z, MXC4005_REG_ZOUT_UPPER),
+};
+
+static int mxc4005_chip_init(struct mxc4005_data *data)
+{
+       int ret;
+       unsigned int reg;
+
+       ret = regmap_read(data->regmap, MXC4005_REG_DEVICE_ID, &reg);
+       if (ret < 0) {
+               dev_err(data->dev, "failed to read chip id\n");
+               return ret;
+       }
+
+       dev_dbg(data->dev, "MXC4005 chip id %02x\n", reg);
+
+       return 0;
+}
+
+static int mxc4005_probe(struct i2c_client *client,
+                        const struct i2c_device_id *id)
+{
+       struct mxc4005_data *data;
+       struct iio_dev *indio_dev;
+       struct regmap *regmap;
+       int ret;
+
+       indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+       if (!indio_dev)
+               return -ENOMEM;
+
+       regmap = devm_regmap_init_i2c(client, &mxc4005_regmap_config);
+       if (IS_ERR(regmap)) {
+               dev_err(&client->dev, "failed to initialize regmap\n");
+               return PTR_ERR(regmap);
+       }
+
+       data = iio_priv(indio_dev);
+       i2c_set_clientdata(client, indio_dev);
+       data->dev = &client->dev;
+       data->regmap = regmap;
+
+       ret = mxc4005_chip_init(data);
+       if (ret < 0) {
+               dev_err(&client->dev, "failed to initialize chip\n");
+               return ret;
+       }
+
+       mutex_init(&data->mutex);
+
+       indio_dev->dev.parent = &client->dev;
+       indio_dev->channels = mxc4005_channels;
+       indio_dev->num_channels = ARRAY_SIZE(mxc4005_channels);
+       indio_dev->name = MXC4005_DRV_NAME;
+       indio_dev->modes = INDIO_DIRECT_MODE;
+       indio_dev->info = &mxc4005_info;
+
+       ret = iio_device_register(indio_dev);
+       if (ret < 0) {
+               dev_err(&client->dev,
+                       "unable to register iio device %d\n", ret);
+               return ret;
+       }
+
+       return 0;
+}
+
+static int mxc4005_remove(struct i2c_client *client)
+{
+       iio_device_unregister(i2c_get_clientdata(client));
+
+       return 0;
+}
+
+static const struct acpi_device_id mxc4005_acpi_match[] = {
+       {"MXC4005",     0},
+       { },
+};
+MODULE_DEVICE_TABLE(acpi, mxc4005_acpi_match);
+
+static const struct i2c_device_id mxc4005_id[] = {
+       {"mxc4005",     0},
+       { },
+};
+MODULE_DEVICE_TABLE(i2c, mxc4005_id);
+
+static struct i2c_driver mxc4005_driver = {
+       .driver = {
+               .name = MXC4005_DRV_NAME,
+               .acpi_match_table = ACPI_PTR(mxc4005_acpi_match),
+       },
+       .probe          = mxc4005_probe,
+       .remove         = mxc4005_remove,
+       .id_table       = mxc4005_id,
+};
+
+module_i2c_driver(mxc4005_driver);
+
+MODULE_AUTHOR("Teodora Baluta <teodora.baluta@intel.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("MXC4005 3-axis accelerometer driver");