Re: [PATCH] iio: adc: max9611: Fix temperature reading in probe

From: Jacopo Mondi
Date: Tue Aug 06 2019 - 03:29:58 EST


Hi Jonathan,

On Mon, Aug 05, 2019 at 06:12:44PM +0100, Jonathan Cameron wrote:
> On Mon, 5 Aug 2019 17:55:15 +0200
> Jacopo Mondi <jacopo+renesas@xxxxxxxxxx> wrote:
>
> > The max9611 driver reads the die temperature at probe time to validate
> > the communication channel. Use the actual read value to perform the test
> > instead of the read function return value, which was mistakenly used so
> > far.
> >
> > The temperature reading test was only successful because the 0 return
> > value is in the range of supported temperatures.
> >
> > Fixes: 69780a3bbc0b ("iio: adc: Add Maxim max9611 ADC driver")
> > Signed-off-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
>
> Applied to the fixes-togreg branch of iio.git and marked for
> stable. That'll be a bit fiddly given other changes around this
> so we may need to do backports.
>

Indeed, I should have mentioned this patch depends on Joe's
ae8cc91a7d85 ("iio: adc: max9611: Fix misuse of GENMASK macro")
which is now in linux-next, otherwise it might atually trigger errors
due to the wrong mask value.

I wonder if there's a way to keep track of these dependencies for the
sake of backporting, or it's an operation that has to be carried out
manually...

Thanks
j

>
> > ---
> > drivers/iio/adc/max9611.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/iio/adc/max9611.c b/drivers/iio/adc/max9611.c
> > index 917223d5ff5b..e9f6b1da1b94 100644
> > --- a/drivers/iio/adc/max9611.c
> > +++ b/drivers/iio/adc/max9611.c
> > @@ -480,7 +480,7 @@ static int max9611_init(struct max9611_dev *max9611)
> > if (ret)
> > return ret;
> >
> > - regval = ret & MAX9611_TEMP_MASK;
> > + regval &= MAX9611_TEMP_MASK;
> >
> > if ((regval > MAX9611_TEMP_MAX_POS &&
> > regval < MAX9611_TEMP_MIN_NEG) ||
> > --
> > 2.22.0
> >
>

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