[PATCH v2 1/3] iio: accel: add support for mxc4005 accelerometer

From: Teodora Baluta
Date: Thu Aug 13 2015 - 13:32:13 EST

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@xxxxxxxxx>
---
drivers/iio/accel/Kconfig | 11 ++
drivers/iio/accel/Makefile | 2 +
drivers/iio/accel/mxc4005.c | 358 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 371 insertions(+)
create mode 100644 drivers/iio/accel/mxc4005.c

diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
index a59047d..69302be 100644
--- a/drivers/iio/accel/Kconfig
+++ b/drivers/iio/accel/Kconfig
@@ -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
diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
index ebd2675..020dda0 100644
--- a/drivers/iio/accel/Makefile
+++ b/drivers/iio/accel/Makefile
@@ -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
index 0000000..76a7954
--- /dev/null
+++ b/drivers/iio/accel/mxc4005.c
@@ -0,0 +1,358 @@
+/*
+ * 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 i2c_client *client;
+ 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_DRV_NAME,
+
+ .reg_bits = 8,
+ .val_bits = 8,
+
+ .max_register = MXC4005_REG_DEVICE_ID,
+ .cache_type = REGCACHE_NONE,
+
+ .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->client->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->client->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->client->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->client->dev, "failed to read chip id\n");
+ return ret;
+ }
+
+ dev_dbg(&data->client->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->client = client;
+ data->regmap = regmap;
+
+ ret = mxc4005_chip_init(data);
+ if (ret < 0) {
+ dev_err(&client->dev, "failed to init 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)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(client);
+
+ iio_device_unregister(indio_dev);
+
+ 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@xxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("MXC4005 3-axis accelerometer driver");
--
1.9.1

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