diff options
Diffstat (limited to 'drivers/iio/accel/dmard09.c')
| -rw-r--r-- | drivers/iio/accel/dmard09.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/drivers/iio/accel/dmard09.c b/drivers/iio/accel/dmard09.c new file mode 100644 index 000000000..16a7e74f5 --- /dev/null +++ b/drivers/iio/accel/dmard09.c @@ -0,0 +1,156 @@ +/* + * IIO driver for the 3-axis accelerometer Domintech DMARD09. + * + * Copyright (c) 2016, Jelle van der Waa <jelle@vdwaa.nl> + * + * 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 <asm/unaligned.h> +#include <linux/module.h> +#include <linux/i2c.h> +#include <linux/iio/iio.h> + +#define DMARD09_DRV_NAME "dmard09" + +#define DMARD09_REG_CHIPID 0x18 +#define DMARD09_REG_STAT 0x0A +#define DMARD09_REG_X 0x0C +#define DMARD09_REG_Y 0x0E +#define DMARD09_REG_Z 0x10 +#define DMARD09_CHIPID 0x95 + +#define DMARD09_BUF_LEN 8 +#define DMARD09_AXIS_X 0 +#define DMARD09_AXIS_Y 1 +#define DMARD09_AXIS_Z 2 +#define DMARD09_AXIS_X_OFFSET ((DMARD09_AXIS_X + 1) * 2) +#define DMARD09_AXIS_Y_OFFSET ((DMARD09_AXIS_Y + 1 )* 2) +#define DMARD09_AXIS_Z_OFFSET ((DMARD09_AXIS_Z + 1) * 2) + +struct dmard09_data { + struct i2c_client *client; +}; + +#define DMARD09_CHANNEL(_axis, offset) { \ + .type = IIO_ACCEL, \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ + .modified = 1, \ + .address = offset, \ + .channel2 = IIO_MOD_##_axis, \ +} + +static const struct iio_chan_spec dmard09_channels[] = { + DMARD09_CHANNEL(X, DMARD09_AXIS_X_OFFSET), + DMARD09_CHANNEL(Y, DMARD09_AXIS_Y_OFFSET), + DMARD09_CHANNEL(Z, DMARD09_AXIS_Z_OFFSET), +}; + +static int dmard09_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct dmard09_data *data = iio_priv(indio_dev); + u8 buf[DMARD09_BUF_LEN]; + int ret; + s16 accel; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + /* + * Read from the DMAR09_REG_STAT register, since the chip + * caches reads from the individual X, Y, Z registers. + */ + ret = i2c_smbus_read_i2c_block_data(data->client, + DMARD09_REG_STAT, + DMARD09_BUF_LEN, buf); + if (ret < 0) { + dev_err(&data->client->dev, "Error reading reg %d\n", + DMARD09_REG_STAT); + return ret; + } + + accel = get_unaligned_le16(&buf[chan->address]); + + /* Remove lower 3 bits and sign extend */ + accel <<= 4; + accel >>= 7; + + *val = accel; + + return IIO_VAL_INT; + default: + return -EINVAL; + } +} + +static const struct iio_info dmard09_info = { + .read_raw = dmard09_read_raw, +}; + +static int dmard09_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + int ret; + struct iio_dev *indio_dev; + struct dmard09_data *data; + + 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; + + ret = i2c_smbus_read_byte_data(data->client, DMARD09_REG_CHIPID); + if (ret < 0) { + dev_err(&client->dev, "Error reading chip id %d\n", ret); + return ret; + } + + if (ret != DMARD09_CHIPID) { + dev_err(&client->dev, "Invalid chip id %d\n", ret); + return -ENODEV; + } + + i2c_set_clientdata(client, indio_dev); + indio_dev->dev.parent = &client->dev; + indio_dev->name = DMARD09_DRV_NAME; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = dmard09_channels; + indio_dev->num_channels = ARRAY_SIZE(dmard09_channels); + indio_dev->info = &dmard09_info; + + return devm_iio_device_register(&client->dev, indio_dev); +} + +static const struct i2c_device_id dmard09_id[] = { + { "dmard09", 0}, + { }, +}; + +MODULE_DEVICE_TABLE(i2c, dmard09_id); + +static struct i2c_driver dmard09_driver = { + .driver = { + .name = DMARD09_DRV_NAME + }, + .probe = dmard09_probe, + .id_table = dmard09_id, +}; + +module_i2c_driver(dmard09_driver); + +MODULE_AUTHOR("Jelle van der Waa <jelle@vdwaa.nl>"); +MODULE_DESCRIPTION("DMARD09 3-axis accelerometer driver"); +MODULE_LICENSE("GPL"); |