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SubjectRe: [PATCH v2] iio: accel: add support for Memsic MXC6255XC sensor
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On 22/10/15 13:44, Teodora Baluta wrote:
> This patch adds a minimal implementation for the Memsic MXC6255XC
> orientation sensing accelerometer. The supported operations are reading
> raw acceleration values for X/Y axis that can be scaled using the
> exposed scale.
>
> Signed-off-by: Teodora Baluta <teodora.baluta@intel.com>
Other than a tiny nitpick below (which I'll fix up when applying)
looks good to me. Small and perfectly formed!

Jonathan
> ---
> Changes since v1:
>
> - remove scale_available attribute
> - use chan->address instead
> - drop _AXIS_TO_REG macro
> - put register address in .address field of MXC6255_CHANNEL macro
> - check chip id
> - use "as follows" instead of "as following"
>
> drivers/iio/accel/Kconfig | 11 +++
> drivers/iio/accel/Makefile | 1 +
> drivers/iio/accel/mxc6255.c | 199 ++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 211 insertions(+)
> create mode 100644 drivers/iio/accel/mxc6255.c
>
> diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
> index 969428d..75ac087 100644
> --- a/drivers/iio/accel/Kconfig
> +++ b/drivers/iio/accel/Kconfig
> @@ -158,6 +158,17 @@ config MXC4005
> To compile this driver as a module, choose M. The module will be
> called mxc4005.
>
> +config MXC6255
> + tristate "Memsic MXC6255 Orientation Sensing Accelerometer Driver"
> + depends on I2C
> + select REGMAP_I2C
> + help
> + Say yes here to build support for the Memsic MXC6255 Orientation
> + Sensing Accelerometer Driver.
> +
> + To compile this driver as a module, choose M here: the module will be
> + called mxc6255.
> +
> 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 7925f16..525ed52 100644
> --- a/drivers/iio/accel/Makefile
> +++ b/drivers/iio/accel/Makefile
> @@ -17,6 +17,7 @@ obj-$(CONFIG_MMA9551) += mma9551.o
> obj-$(CONFIG_MMA9553) += mma9553.o
>
> obj-$(CONFIG_MXC4005) += mxc4005.o
> +obj-$(CONFIG_MXC6255) += mxc6255.o
>
> obj-$(CONFIG_STK8312) += stk8312.o
> obj-$(CONFIG_STK8BA50) += stk8ba50.o
> diff --git a/drivers/iio/accel/mxc6255.c b/drivers/iio/accel/mxc6255.c
> new file mode 100644
> index 0000000..b853ff0
> --- /dev/null
> +++ b/drivers/iio/accel/mxc6255.c
> @@ -0,0 +1,199 @@
> +/*
> + * MXC6255 - MEMSIC orientation sensing accelerometer
> + *
> + * Copyright (c) 2015, Intel Corporation.
> + *
> + * This file is subject to the terms and conditions of version 2 of
> + * the GNU General Public License. See the file COPYING in the main
> + * directory of this archive for more details.
> + *
> + * IIO driver for MXC6255 (7-bit I2C slave address 0x15).
No need for the blank line below.
> + *
> + */
> +
> +#include <linux/module.h>
> +#include <linux/i2c.h>
> +#include <linux/init.h>
> +#include <linux/iio/iio.h>
> +#include <linux/delay.h>
> +#include <linux/acpi.h>
> +#include <linux/regmap.h>
> +#include <linux/iio/sysfs.h>
> +
> +#define MXC6255_DRV_NAME "mxc6255"
> +#define MXC6255_REGMAP_NAME "mxc6255_regmap"
> +
> +#define MXC6255_REG_XOUT 0x00
> +#define MXC6255_REG_YOUT 0x01
> +#define MXC6255_REG_CHIP_ID 0x08
> +
> +#define MXC6255_CHIP_ID 0x05
> +
> +/*
> + * MXC6255 has only one measurement range: +/- 2G.
> + * The acceleration output is an 8-bit value.
> + *
> + * Scale is calculated as follows:
> + * (2 + 2) * 9.80665 / (2^8 - 1) = 0.153829
> + *
> + * Scale value for +/- 2G measurement range
> + */
> +#define MXC6255_SCALE 153829
> +
> +enum mxc6255_axis {
> + AXIS_X,
> + AXIS_Y,
> +};
> +
> +struct mxc6255_data {
> + struct i2c_client *client;
> + struct regmap *regmap;
> +};
> +
> +static int mxc6255_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int *val, int *val2, long mask)
> +{
> + struct mxc6255_data *data = iio_priv(indio_dev);
> + unsigned int reg;
> + int ret;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + ret = regmap_read(data->regmap, chan->address, &reg);
> + if (ret < 0) {
> + dev_err(&data->client->dev,
> + "Error reading reg %lu\n", chan->address);
> + return ret;
> + }
> +
> + *val = sign_extend32(reg, 7);
> + return IIO_VAL_INT;
> + case IIO_CHAN_INFO_SCALE:
> + *val = 0;
> + *val2 = MXC6255_SCALE;
> + return IIO_VAL_INT_PLUS_MICRO;
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static const struct iio_info mxc6255_info = {
> + .driver_module = THIS_MODULE,
> + .read_raw = mxc6255_read_raw,
> +};
> +
> +#define MXC6255_CHANNEL(_axis, reg) { \
> + .type = IIO_ACCEL, \
> + .modified = 1, \
> + .channel2 = IIO_MOD_##_axis, \
> + .address = reg, \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
> +}
> +
> +static const struct iio_chan_spec mxc6255_channels[] = {
> + MXC6255_CHANNEL(X, MXC6255_REG_XOUT),
> + MXC6255_CHANNEL(Y, MXC6255_REG_YOUT),
> +};
> +
> +static bool mxc6255_is_readable_reg(struct device *dev, unsigned int reg)
> +{
> + switch (reg) {
> + case MXC6255_REG_XOUT:
> + case MXC6255_REG_YOUT:
> + case MXC6255_REG_CHIP_ID:
> + return true;
> + default:
> + return false;
> + }
> +}
> +
> +static const struct regmap_config mxc6255_regmap_config = {
> + .name = MXC6255_REGMAP_NAME,
> +
> + .reg_bits = 8,
> + .val_bits = 8,
> +
> + .readable_reg = mxc6255_is_readable_reg,
> +};
> +
> +static int mxc6255_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct mxc6255_data *data;
> + struct iio_dev *indio_dev;
> + struct regmap *regmap;
> + unsigned int chip_id;
> + int ret;
> +
> + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
> + if (!indio_dev)
> + return -ENOMEM;
> +
> + regmap = devm_regmap_init_i2c(client, &mxc6255_regmap_config);
> + if (IS_ERR(regmap)) {
> + dev_err(&client->dev, "Error initializing regmap\n");
> + return PTR_ERR(regmap);
> + }
> +
> + data = iio_priv(indio_dev);
> + i2c_set_clientdata(client, indio_dev);
> + data->client = client;
> + data->regmap = regmap;
> +
> + indio_dev->name = MXC6255_DRV_NAME;
> + indio_dev->dev.parent = &client->dev;
> + indio_dev->channels = mxc6255_channels;
> + indio_dev->num_channels = ARRAY_SIZE(mxc6255_channels);
> + indio_dev->modes = INDIO_DIRECT_MODE;
> + indio_dev->info = &mxc6255_info;
> +
> + ret = regmap_read(data->regmap, MXC6255_REG_CHIP_ID, &chip_id);
> + if (ret < 0) {
> + dev_err(&client->dev, "Error reading chip id %d\n", ret);
> + return ret;
> + }
> +
> + if (chip_id != MXC6255_CHIP_ID) {
> + dev_err(&client->dev, "Invalid chip id %x\n", chip_id);
> + return -ENODEV;
> + }
> +
> + dev_dbg(&client->dev, "Chip id %x\n", chip_id);
> +
> + ret = devm_iio_device_register(&client->dev, indio_dev);
> + if (ret < 0) {
> + dev_err(&client->dev, "Could not register IIO device\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static const struct acpi_device_id mxc6255_acpi_match[] = {
> + {"MXC6255", 0},
> + { }
> +};
> +MODULE_DEVICE_TABLE(acpi, mxc6255_acpi_match);
> +
> +static const struct i2c_device_id mxc6255_id[] = {
> + {"mxc6255", 0},
> + { }
> +};
> +MODULE_DEVICE_TABLE(i2c, mxc6255_id);
> +
> +static struct i2c_driver mxc6255_driver = {
> + .driver = {
> + .name = MXC6255_DRV_NAME,
> + .acpi_match_table = ACPI_PTR(mxc6255_acpi_match),
> + },
> + .probe = mxc6255_probe,
> + .id_table = mxc6255_id,
> +};
> +
> +module_i2c_driver(mxc6255_driver);
> +
> +MODULE_AUTHOR("Teodora Baluta <teodora.baluta@intel.com>");
> +MODULE_DESCRIPTION("MEMSIC MXC6255 orientation sensing accelerometer driver");
> +MODULE_LICENSE("GPL v2");
>



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