Re: [PATCH 04/10] iio: adc: stm32-dfsdm: Avoid dereferencing ->currentmode

[Alexandru Ardelean <ardeleanalex@gmail.com>]

On Wed, Dec 15, 2021 at 10:03 PM Miquel Raynal
<miquel.raynal@bootlin.com> wrote:
>
> This is an internal variable of the core, let's use the
> iio_buffer_enabled() helper which is exported for the following purpose:
> telling if the current mode is a buffered mode, which is precisely what
> this driver looks for.
>
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> ---
>  drivers/iio/adc/stm32-dfsdm-adc.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c
> index 1cfefb3b5e56..a3b8827d3bbf 100644
> --- a/drivers/iio/adc/stm32-dfsdm-adc.c
> +++ b/drivers/iio/adc/stm32-dfsdm-adc.c
> @@ -466,8 +466,7 @@ static int stm32_dfsdm_channels_configure(struct iio_dev *indio_dev,
>          * In continuous mode, use fast mode configuration,
>          * if it provides a better resolution.
>          */
> -       if (adc->nconv == 1 && !trig &&
> -           (indio_dev->currentmode & INDIO_BUFFER_SOFTWARE)) {
> +       if (adc->nconv == 1 && !trig && iio_buffer_enabled(indio_dev)) {

This may become tricky if other modes get added later.
STM does a relatively good job in updating and re-using their drivers
(even if some of them do look quirky sometimes).

So, the question here would be: is "iio_buffer_enabled(indio_dev)"
going to be valid [in this place] once INDIO_BUFFER_TRIGGERED or
INDIO_BUFFER_HARDWARE get added?

I'd also ping some STM people for some feedback, acks or testing.

>                 if (fl->flo[1].res >= fl->flo[0].res) {
>                         fl->fast = 1;
>                         flo = &fl->flo[1];
> @@ -562,7 +561,7 @@ static int stm32_dfsdm_filter_configure(struct iio_dev *indio_dev,
>                 cr1 = DFSDM_CR1_RCH(chan->channel);
>
>                 /* Continuous conversions triggered by SPI clk in buffer mode */
> -               if (indio_dev->currentmode & INDIO_BUFFER_SOFTWARE)
> +               if (iio_buffer_enabled(indio_dev))
>                         cr1 |= DFSDM_CR1_RCONT(1);
>
>                 cr1 |= DFSDM_CR1_RSYNC(fl->sync_mode);
> --
> 2.27.0
>