On Mon, May 9, 2022 at 4:46 PM LI Qingwu
<Qing-wu.Li@xxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> The units after application of scale are 100*m/s^2,
> The scale calculation is only for the device
> with the range of 3, 6, 12, and 24g,
> but some other chips have a range of 2, 4, 6, and 8g.
>
> Modified the formula to a scale list.
> The scales in the list are calculated by 1/sensitivity*9.8.
> The new units after the application of scale are m/s^2.
>
> Signed-off-by: LI Qingwu <Qing-wu.Li@xxxxxxxxxxxxxxxxxxxxxxx>
> ---
> drivers/iio/accel/bmi088-accel-core.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/iio/accel/bmi088-accel-core.c b/drivers/iio/accel/bmi088-accel-core.c
> index a06dae5c971d..0c58ffdd00e3 100644
> --- a/drivers/iio/accel/bmi088-accel-core.c
> +++ b/drivers/iio/accel/bmi088-accel-core.c
> @@ -119,6 +119,7 @@ struct bmi088_accel_chip_info {
> u8 chip_id;
> const struct iio_chan_spec *channels;
> int num_channels;
> + const int scale_table[4][2];
> };
>
> struct bmi088_accel_data {
> @@ -280,6 +281,7 @@ static int bmi088_accel_read_raw(struct iio_dev *indio_dev,
> struct bmi088_accel_data *data = iio_priv(indio_dev);
> struct device *dev = regmap_get_device(data->regmap);
> int ret;
> + int reg;
>
> switch (mask) {
> case IIO_CHAN_INFO_RAW:
> @@ -330,13 +332,12 @@ static int bmi088_accel_read_raw(struct iio_dev *indio_dev,
> return ret;
>
> ret = regmap_read(data->regmap,
> - BMI088_ACCEL_REG_ACC_RANGE, val);
> + BMI088_ACCEL_REG_ACC_RANGE, ®);
Curios: do we need to validate the value of `reg` here?
If it goes outside of the 0...3 range, I can see a bit of access
violation (kernel panic) happening.
> if (ret)
> goto out_read_raw_pm_put;
> -
> - *val2 = 15 - (*val & 0x3);
> - *val = 3 * 980;
> - ret = IIO_VAL_FRACTIONAL_LOG2;
Not sure what the policy is about changing this now.
I'll leave this to Jonathan.
> + *val = data->chip_info->scale_table[reg][0];
> + *val2 = data->chip_info->scale_table[reg][1];
> + ret = IIO_VAL_INT_PLUS_MICRO;
>
> goto out_read_raw_pm_put;
> default:
> @@ -432,6 +433,7 @@ static const struct bmi088_accel_chip_info bmi088_accel_chip_info_tbl[] = {
> .chip_id = 0x1E,
> .channels = bmi088_accel_channels,
> .num_channels = ARRAY_SIZE(bmi088_accel_channels),
> + .scale_table = {{0, 897}, {0, 1795}, {0, 3590}, {0, 7179}},
I like the idea of this scale_table.
It makes things easier to see (what's happening) without looking into
the datasheet much.
> },
> };
>
> --
> 2.25.1
>
