On Wed, 15 Feb 2023 02:16:40 +0000
Bough Chen <haibo.chen@xxxxxxx> wrote:
> > -----Original Message-----
> > From: Dan Carpenter <error27@xxxxxxxxx>
> > Sent: 2023年2月14日 23:48
> > To: Bough Chen <haibo.chen@xxxxxxx>
> > Cc: Jonathan Cameron <jic23@xxxxxxxxxx>; Lars-Peter Clausen
> > <lars@xxxxxxxxxx>; Shawn Guo <shawnguo@xxxxxxxxxx>; Sascha Hauer
> > <s.hauer@xxxxxxxxxxxxxx>; Pengutronix Kernel Team
> > <kernel@xxxxxxxxxxxxxx>; Fabio Estevam <festevam@xxxxxxxxx>; dl-linux-imx
> > <linux-imx@xxxxxxx>; linux-iio@xxxxxxxxxxxxxxx;
> > kernel-janitors@xxxxxxxxxxxxxxx
> > Subject: [PATCH] iio: adc: imx93: fix a signedness bug in imx93_adc_read_raw()
> >
> > The problem is these lines:
> >
> > ret = vref_uv = regulator_get_voltage(adc->vref);
> > if (ret < 0)
> >
> > The "ret" variable is type long and "vref_uv" is u32 so that means the condition
> > can never be true on a 64bit system. A negative error code from
> > regulator_get_voltage() would be cast to a high positive
> > u32 value and then remain a high positive value when cast to a long.
> >
> > The "ret" variable only ever stores ints so it should be declared as an int. We
> > can delete the "vref_uv" variable and use "ret" directly.
>
> Thanks for the catching!
>
> Reviewed-by: Haibo Chen <haibo.chen@xxxxxxx>
Applied to the fixes-togreg branch of iio.git.
Thanks
Jonathan
>
> Best Regards
> Haibo Chen
> >
> > Fixes: 7d02296ac8b8 ("iio: adc: add imx93 adc support")
> > Signed-off-by: Dan Carpenter <error27@xxxxxxxxx>
> > ---
> > drivers/iio/adc/imx93_adc.c | 7 +++----
> > 1 file changed, 3 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/iio/adc/imx93_adc.c b/drivers/iio/adc/imx93_adc.c index
> > d8de8284e13d..8c68f0cd48f2 100644
> > --- a/drivers/iio/adc/imx93_adc.c
> > +++ b/drivers/iio/adc/imx93_adc.c
> > @@ -236,8 +236,7 @@ static int imx93_adc_read_raw(struct iio_dev
> > *indio_dev, {
> > struct imx93_adc *adc = iio_priv(indio_dev);
> > struct device *dev = adc->dev;
> > - long ret;
> > - u32 vref_uv;
> > + int ret;
> >
> > switch (mask) {
> > case IIO_CHAN_INFO_RAW:
> > @@ -253,10 +252,10 @@ static int imx93_adc_read_raw(struct iio_dev
> > *indio_dev,
> > return IIO_VAL_INT;
> >
> > case IIO_CHAN_INFO_SCALE:
> > - ret = vref_uv = regulator_get_voltage(adc->vref);
> > + ret = regulator_get_voltage(adc->vref);
> > if (ret < 0)
> > return ret;
> > - *val = vref_uv / 1000;
> > + *val = ret / 1000;
> > *val2 = 12;
> > return IIO_VAL_FRACTIONAL_LOG2;
> >
> > --
> > 2.35.1
>
