Re: [PATCH] iio: invensense: fix odr switching to same value

[Jonathan Cameron <jic23@kernel.org>]

On Fri, 24 May 2024 12:48:51 +0000
inv.git-commit@tdk.com wrote:

> From: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
> 
> ODR switching happens in 2 steps, update to store the new value and then
> apply when the ODR change flag is received in the data. When switching to
> the same ODR value, the ODR change flag is never happening, and frequency
> switching is blocked waiting for the never coming apply.
> 
> Fix the issue by preventing update to happen when switching to same ODR
> value.
> 
> Fixes: 0ecc363ccea7 ("iio: make invensense timestamp module generic")
> Cc: stable@vger.kernel.org
> Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>

Applied to the fixes-togreg branch of iio.git

Note I'll rebase that tree on rc1 once available.

> ---
>  drivers/iio/common/inv_sensors/inv_sensors_timestamp.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/common/inv_sensors/inv_sensors_timestamp.c b/drivers/iio/common/inv_sensors/inv_sensors_timestamp.c
> index fa205f17bd90..f44458c380d9 100644
> --- a/drivers/iio/common/inv_sensors/inv_sensors_timestamp.c
> +++ b/drivers/iio/common/inv_sensors/inv_sensors_timestamp.c
> @@ -60,11 +60,15 @@ EXPORT_SYMBOL_NS_GPL(inv_sensors_timestamp_init, IIO_INV_SENSORS_TIMESTAMP);
>  int inv_sensors_timestamp_update_odr(struct inv_sensors_timestamp *ts,
>  				     uint32_t period, bool fifo)
>  {
> +	uint32_t mult;
> +
>  	/* when FIFO is on, prevent odr change if one is already pending */
>  	if (fifo && ts->new_mult != 0)
>  		return -EAGAIN;
>  
> -	ts->new_mult = period / ts->chip.clock_period;
> +	mult = period / ts->chip.clock_period;
> +	if (mult != ts->mult)
> +		ts->new_mult = mult;
>  
>  	return 0;
>  }