diff options
Diffstat (limited to 'drivers/iio/accel/mxc6255.c')
| -rw-r--r-- | drivers/iio/accel/mxc6255.c | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/drivers/iio/accel/mxc6255.c b/drivers/iio/accel/mxc6255.c new file mode 100644 index 000000000..ddd50d178 --- /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). + */ + +#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, ®); + 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 = { + .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 & 0x1f) != 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[] = { + {"MXC6225", 0}, + {"MXC6255", 0}, + { } +}; +MODULE_DEVICE_TABLE(acpi, mxc6255_acpi_match); + +static const struct i2c_device_id mxc6255_id[] = { + {"mxc6225", 0}, + {"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"); |