> Minimal implementation of an IIO driver for the Domintech DMARD09 3-axis
> accelerometer. Only supports reading the x,y,z axes at the moment.
comments below
> Implementation based on the Android driver from the Acer Liquid E2
> kernel sources.
>
> Signed-off-by: Jelle van der Waa <jelle@xxxxxxxx>
> ---
> .../devicetree/bindings/iio/accel/dmard09.txt | 13 ++
> drivers/iio/accel/Kconfig | 10 ++
> drivers/iio/accel/Makefile | 1 +
> drivers/iio/accel/dmard09.c | 180 +++++++++++++++++++++
> 4 files changed, 204 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/iio/accel/dmard09.txt
> create mode 100644 drivers/iio/accel/dmard09.c
>
> diff --git a/Documentation/devicetree/bindings/iio/accel/dmard09.txt b/Documentation/devicetree/bindings/iio/accel/dmard09.txt
> new file mode 100644
> index 0000000..69b2a03
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/accel/dmard09.txt
> @@ -0,0 +1,13 @@
> +Domintech DMARD09 accelerometer devicetree bindings
> +
> +Required properties:
> +
> + - compatible : should be "domintech,dmard09"
> + - reg : the I2C address of the sensor
> +
> +Example:
> +
> +dmard09@0x1d {
> + compatible = "domintech,dmard09";
> + reg = <0x1d>;
> +};
> diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
> index e4a758c..3fb16eb 100644
> --- a/drivers/iio/accel/Kconfig
> +++ b/drivers/iio/accel/Kconfig
> @@ -40,6 +40,16 @@ config BMC150_ACCEL_SPI
> tristate
> select REGMAP_SPI
>
> +config DMARD09
> + tristate "Domintech DMARD09 3-axis Accelerometer Driver"
> + select I2C
> + help
> + Say yes here to get support for the Domintech DMARD09 3-axis
> + accelerometer.
> +
> + Choosing M will build the driver as a module. If so, the module
> + will be called dmard09.
> +
> config HID_SENSOR_ACCEL_3D
> depends on HID_SENSOR_HUB
> select IIO_BUFFER
> diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
> index 71b6794..b1022a0 100644
> --- a/drivers/iio/accel/Makefile
> +++ b/drivers/iio/accel/Makefile
> @@ -7,6 +7,7 @@ obj-$(CONFIG_BMA180) += bma180.o
> obj-$(CONFIG_BMC150_ACCEL) += bmc150-accel-core.o
> obj-$(CONFIG_BMC150_ACCEL_I2C) += bmc150-accel-i2c.o
> obj-$(CONFIG_BMC150_ACCEL_SPI) += bmc150-accel-spi.o
> +obj-$(CONFIG_DMARD09) += dmard09.o
> obj-$(CONFIG_HID_SENSOR_ACCEL_3D) += hid-sensor-accel-3d.o
> obj-$(CONFIG_KXCJK1013) += kxcjk-1013.o
> obj-$(CONFIG_KXSD9) += kxsd9.o
> diff --git a/drivers/iio/accel/dmard09.c b/drivers/iio/accel/dmard09.c
> new file mode 100644
> index 0000000..8689c5a
> --- /dev/null
> +++ b/drivers/iio/accel/dmard09.c
> @@ -0,0 +1,180 @@
> +/*
> + * 3-axis accelerometer driver for DMARD09 3-axis sensor.
remove extra space at beginning of line
3-axis mentioned twice
> + *
> + * Copyright (c) 2016, Jelle van der Waa <jelle@xxxxxxxx>
> + *
> + * 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>
> +
> +#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_AXES_NUM 3
> +#define DMARD09_AXIS_X 0
> +#define DMARD09_AXIS_Y 1
> +#define DMARD09_AXIS_Z 2
> +
> +/* Used for dev_info() */
> +struct dmard09_data {
> + struct i2c_client *client;
> + struct device *dev;
what is this good for? use client->dev?
> +};
> +
> +static const struct iio_chan_spec dmard09_channels[] = {
a #define would help to write this in a more concise way
> + {
> + .type = IIO_ACCEL,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
> + .modified = 1,
> + .address = DMARD09_REG_X,
I suggest to store _AXIS_N here or rather AXIS_N_OFFSET which would be
(AXIS+1)*2
> + .channel2 = IIO_MOD_X,
> + },
> + {
> + .type = IIO_ACCEL,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
> + .modified = 1,
> + .address = DMARD09_REG_Y,
> + .channel2 = IIO_MOD_Y,
> + },
> + {
> + .type = IIO_ACCEL,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
> + .modified = 1,
> + .address = DMARD09_REG_Z,
> + .channel2 = IIO_MOD_Z,
> + }
> +};
> +
> +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] = {0};
why initialize buf?
> + int ret;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + ret = i2c_smbus_read_i2c_block_data(data->client,
> + DMARD09_REG_STAT,
> + DMARD09_BUF_LEN, buf);
> + if (ret < 0) {
a comment explaining the read stragegy would be nice
I guess that _STAT would have some information if the data is
ready/valid? why not start reading at AXIS_X?
> + dev_err(data->dev, "Error reading reg %lu\n",
> + chan->address);
> + return ret;
> + }
> +
check stat?
the if block is not necessary, maybe
*val = (s16) le16_to_cpup(&buf[chan->address])
where chan->address is the offset into buf
> + if (chan->address == DMARD09_REG_X)
> + *val = (s16)((buf[(DMARD09_AXIS_X+1)*2+1] << 8)
> + | (buf[(DMARD09_AXIS_X+1)*2]));
> + if (chan->address == DMARD09_REG_Y)
> + *val = (s16)((buf[(DMARD09_AXIS_Y+1)*2+1] << 8)
> + | (buf[(DMARD09_AXIS_Y+1)*2]));
> + if (chan->address == DMARD09_REG_Z)
> + *val = (s16)((buf[(DMARD09_AXIS_Z+1)*2+1] << 8)
> + | (buf[(DMARD09_AXIS_Z+1)*2]));
> +
> + return IIO_VAL_INT;
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static const struct iio_info dmard09_info = {
> + .driver_module = THIS_MODULE,
> + .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->dev = &client->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 = DMARD09_AXES_NUM;
I suggest ARRAY_SIZE(dmard09_channels)
> + indio_dev->info = &dmard09_info;
> +
> + ret = iio_device_register(indio_dev);
could use devm_iio_device_register, just
return devm_iio_device_register(...) and drop the if
> + if (ret < 0)
> + return ret;
> +
> + return 0;
> +}
> +
> +static int dmard09_remove(struct i2c_client *client)
> +{
> + struct iio_dev *indio_dev = i2c_get_clientdata(client);
> +
> + iio_device_unregister(indio_dev);
> +
> + return 0;
> +}
> +
> +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,
> + .remove = dmard09_remove,
> + .id_table = dmard09_id,
> +};
> +
> +module_i2c_driver(dmard09_driver);
> +
> +MODULE_AUTHOR("Jelle van der Waa <jelle@xxxxxxxx>");
> +MODULE_DESCRIPTION("DMARD09 3-axis accelerometer driver");
> +MODULE_LICENSE("GPL");
>
--
Peter Meerwald-Stadler
+43-664-2444418 (mobile)
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