Re: [PATCH] iio: imu: st_lsm6dsx: set 10ms as min shub slave timeout

[Jonathan Cameron <jic23@kernel.org>]

On Wed, 21 Oct 2020 23:53:54 +0200
Lorenzo Bianconi <lorenzo@kernel.org> wrote:

> Set 10ms as minimum i2c slave configuration timeout since at high ODRs
> (e.g. 833Hz) the slave sensor may need more cycles than ~3ms
> (2s/833Hz + 1) for the configuration
> 
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>

Hi Lorenzo,

This sounds like a fix to me.  Could you give a bit more detail on what
setup it fails for and a fixes tag so we can get this into appropriate
stable trees?

Thanks,

Jonathan

> ---
>  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c
> index 8c8d8870ca07..99562ba85ee4 100644
> --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c
> +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c
> @@ -156,11 +156,13 @@ static const struct st_lsm6dsx_ext_dev_settings st_lsm6dsx_ext_dev_table[] = {
>  static void st_lsm6dsx_shub_wait_complete(struct st_lsm6dsx_hw *hw)
>  {
>  	struct st_lsm6dsx_sensor *sensor;
> -	u32 odr;
> +	u32 odr, timeout;
>  
>  	sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_ACC]);
>  	odr = (hw->enable_mask & BIT(ST_LSM6DSX_ID_ACC)) ? sensor->odr : 12500;
> -	msleep((2000000U / odr) + 1);
> +	/* set 10ms as minimum timeout for i2c slave configuration */
> +	timeout = max_t(u32, 2000000U / odr + 1, 10);
> +	msleep(timeout);
>  }
>  
>  /*