On Tue, 4 Feb 2025 12:50:23 +0100
Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxx> wrote:
> If one or more of the 16 channels are enabled and the driver is not
> aware of that, unexpected things happen because different channels are
> used than intended. To prevent that, all channels should be disabled at
> probe time. In Commit 4be339af334c ("iio: adc: ad7124: Disable all
> channels at probe time") I intended do that, however only the channels
> that are potentially used by the driver and not all channels are
> disabled since then. So disable all 16 channels and not only the used
> ones.
>
> Also fix the same issue in the .disable_all() callback.
>
> Fixes: 4be339af334c ("iio: adc: ad7124: Disable all channels at probe time")
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxx>
I've applied this on the togreg branch of iio.git but you may need
to do a manual backport of the fix to get it on 6.14 once that's
released.
Jonathan
> ---
> Hello,
>
> this patch is based on v6.14-rc1 + the patch "iio: adc: ad7124: Micro-optimize
> channel disabling"
> (https://lore.kernel.org/linux-iio/20250120140708.1093655-2-u.kleine-koenig@xxxxxxxxxxxx)
> that Jonathan claimed to have taken already.
>
> Best regards
> Uwe
>
> drivers/iio/adc/ad7124.c | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/iio/adc/ad7124.c b/drivers/iio/adc/ad7124.c
> index 2fdeb3247952..6bc418d38820 100644
> --- a/drivers/iio/adc/ad7124.c
> +++ b/drivers/iio/adc/ad7124.c
> @@ -550,11 +550,10 @@ static int ad7124_disable_one(struct ad_sigma_delta *sd, unsigned int chan)
>
> static int ad7124_disable_all(struct ad_sigma_delta *sd)
> {
> - struct ad7124_state *st = container_of(sd, struct ad7124_state, sd);
> int ret;
> int i;
>
> - for (i = 0; i < st->num_channels; i++) {
> + for (i = 0; i < 16; i++) {
> ret = ad7124_disable_one(sd, i);
> if (ret < 0)
> return ret;
> @@ -1017,11 +1016,10 @@ static int ad7124_setup(struct ad7124_state *st)
> * set all channels to this default value.
> */
> ad7124_set_channel_odr(st, i, 10);
> -
> - /* Disable all channels to prevent unintended conversions. */
> - ad_sd_write_reg(&st->sd, AD7124_CHANNEL(i), 2, 0);
> }
>
> + ad7124_disable_all(&st->sd);
> +
> ret = ad_sd_write_reg(&st->sd, AD7124_ADC_CONTROL, 2, st->adc_control);
> if (ret < 0)
> return dev_err_probe(dev, ret, "Failed to setup CONTROL register\n");
>
> base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b
> prerequisite-patch-id: c8d3727852b9c3bb4dcd2f16508bebbd093a3768
