On Tue, Aug 1, 2017 at 11:26 AM, Ladislav Michl <ladis@xxxxxxxxxxxxxx> wrote:
> When reading diffrent channel value than device is currently processing
> wait time of conversion period is applied, which is not enough as device
> might be already in the middle of conversion and therefore previously
> converted value is returned - the one belonging to another channel.
> Fix it by waiting for two sampling periods.
>
> Signed-off-by: Ladislav Michl <ladis@xxxxxxxxxxxxxx>
Did you actually experienced this in practice? I guess you are right,
if you change the channel during a conversion, this change will be applied
to the next conversion *but* reading will still return old value because the
current conversion hasn't finished yet.
So,
Acked-by: Daniel Baluta <daniel.baluta@xxxxxxxxx>
> ---
> drivers/iio/adc/ti-ads1015.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/iio/adc/ti-ads1015.c b/drivers/iio/adc/ti-ads1015.c
> index 884b8e461b17..86fd2753869d 100644
> --- a/drivers/iio/adc/ti-ads1015.c
> +++ b/drivers/iio/adc/ti-ads1015.c
> @@ -260,7 +260,7 @@ int ads1015_get_adc_result(struct ads1015_data *data, int chan, int *val)
> return ret;
>
> if (change) {
> - conv_time = DIV_ROUND_UP(USEC_PER_SEC, data->data_rate[dr]);
> + conv_time = 2 * DIV_ROUND_UP(USEC_PER_SEC, data->data_rate[dr]);
> usleep_range(conv_time, conv_time + 1);
> }
>
> --
> 2.11.0
>
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