Re: [PATCH] iio: adc: ad7192: Avoid disabling a clock that was never enabled.

[Jonathan Cameron <Jonathan.Cameron@Huawei.com>]

On Mon, 10 May 2021 14:30:48 +0300
Alexandru Ardelean <ardeleanalex@gmail.com> wrote:

> On Sun, May 9, 2021 at 2:42 PM Jonathan Cameron <jic23@kernel.org> wrote:
> >
> > From: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> >
> > Found by inspection.
> >
> > If the internal clock source is being used, the driver doesn't
> > call clk_prepare_enable() and as such we should not call
> > clk_disable_unprepare()
> >
> > Use the same condition to protect the disable path as is used
> > on the enable one.  Note this will all get simplified when
> > the driver moves over to a full devm_ flow, but that would make
> > backporting the fix harder.
> >
> > Fix obviously predates move out of staging, but backporting will
> > become more complex (and is unlikely to happen), hence that patch
> > is given in the fixes tag.
> >  
> 
> This also looks like a conversion to devm_ would help.
> But later.

Absolutely.  I decided to do a pre parse of likely targets for
devmification to see if we had fixed that needed to go first and
that's when I noticed this one.

That way we don't end up with the mess I caused in the previous
set where I have to remember to finally pick up the non fix
part after the fixes are in.

Jonathan

> 
> Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>

> 
> > Fixes: b581f748cce0 ("staging: iio: adc: ad7192: move out of staging")
> > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> > Cc: Alexandru Tachici <alexandru.tachici@analog.com>
> > Cc: Alexandru Ardelean <ardeleanalex@gmail.com>
> > ---
> >  drivers/iio/adc/ad7192.c | 8 ++++++--
> >  1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/iio/adc/ad7192.c b/drivers/iio/adc/ad7192.c
> > index 2ed580521d81..d3be67aa0522 100644
> > --- a/drivers/iio/adc/ad7192.c
> > +++ b/drivers/iio/adc/ad7192.c
> > @@ -1014,7 +1014,9 @@ static int ad7192_probe(struct spi_device *spi)
> >         return 0;
> >
> >  error_disable_clk:
> > -       clk_disable_unprepare(st->mclk);
> > +       if (st->clock_sel == AD7192_CLK_EXT_MCLK1_2 ||
> > +           st->clock_sel == AD7192_CLK_EXT_MCLK2)
> > +               clk_disable_unprepare(st->mclk);
> >  error_remove_trigger:
> >         ad_sd_cleanup_buffer_and_trigger(indio_dev);
> >  error_disable_dvdd:
> > @@ -1031,7 +1033,9 @@ static int ad7192_remove(struct spi_device *spi)
> >         struct ad7192_state *st = iio_priv(indio_dev);
> >
> >         iio_device_unregister(indio_dev);
> > -       clk_disable_unprepare(st->mclk);
> > +       if (st->clock_sel == AD7192_CLK_EXT_MCLK1_2 ||
> > +           st->clock_sel == AD7192_CLK_EXT_MCLK2)
> > +               clk_disable_unprepare(st->mclk);
> >         ad_sd_cleanup_buffer_and_trigger(indio_dev);
> >
> >         regulator_disable(st->dvdd);
> > --
> > 2.31.1
> >