> -----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>
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
