On 10/16/2015 12:29 PM, 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.bal...@intel.com>
Looks quite good in general, a few minor things inline.
[...]
> +/* scale value for +/- 2G measurement range */
> +static const int mxc6255_scale = 153829;
> +
> +static IIO_CONST_ATTR(in_accel_scale_available, MXC6255_SCALE_AVAIL);
If there is only one scale available it does not make too much sense to have
a scale_available attribute.
[..]
> +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 axis = chan->channel2 - 1;
1 is a bit of a magic constant here. Use IIO_MOD_X instead. Or even better
use chan->address.
> + int ret;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + ret = regmap_read(data->regmap,
> + MXC6255_AXIS_TO_REG(axis), ®);
> + if (ret < 0) {
> + dev_err(&data->client->dev,
> + "Error reading axis %d\n", axis);
> + 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 int mxc6255_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
[...]
> + 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;
> + }
Does it make sense to check whether chip ID matches the expected value, to
catch mistakes where the I2C address is incorrect?
> +
> + 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;
> +}
[...]
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