On Sat, 5 Oct 2024 22:37:22 +0530
Mohammed Anees <pvmohammedanees2003@xxxxxxxxx> wrote:
> In the current implementation of the ltc2664_channel_config function,
> a variable named span is declared and initialized to 0, intended to
> capture the return value of the ltc2664_set_span function. However,
> the output of ltc2664_set_span is directly assigned to chan->span,
> leaving span unchanged. As a result, when the function later checks
> if (span < 0), this condition will never trigger an error since
> span remains 0, this flaw leads to ineffective error handling. The
> current patch resolves this issue by using the ret variable for
> getting the return value, later assigning if successful and also
> effectively removing span variable.
>
> Signed-off-by: Mohammed Anees <pvmohammedanees2003@xxxxxxxxx>
> Fixes: 4cc2fc445d2e4e63ed6bd5d310752d88d365f8e4
> ---
> v2:
> - Using the ret variable to store the result from ltc2664_set_span
> ---
> drivers/iio/dac/ltc2664.c | 18 +++++++++++-------
> 1 file changed, 11 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/iio/dac/ltc2664.c b/drivers/iio/dac/ltc2664.c
> index 5be5345ac5c8..7dafcba7ece7 100644
> --- a/drivers/iio/dac/ltc2664.c
> +++ b/drivers/iio/dac/ltc2664.c
> @@ -516,7 +516,7 @@ static int ltc2664_channel_config(struct ltc2664_state *st)
> const struct ltc2664_chip_info *chip_info = st->chip_info;
> struct device *dev = &st->spi->dev;
> u32 reg, tmp[2], mspan;
> - int ret, span = 0;
> + int ret;
>
> mspan = LTC2664_MSPAN_SOFTSPAN;
> ret = device_property_read_u32(dev, "adi,manual-span-operation-config",
> @@ -579,20 +579,24 @@ static int ltc2664_channel_config(struct ltc2664_state *st)
> ret = fwnode_property_read_u32_array(child, "output-range-microvolt",
> tmp, ARRAY_SIZE(tmp));
> if (!ret && mspan == LTC2664_MSPAN_SOFTSPAN) {
> - chan->span = ltc2664_set_span(st, tmp[0] / 1000,
> + ret = ltc2664_set_span(st, tmp[0] / 1000,
> tmp[1] / 1000, reg);
> - if (span < 0)
> - return dev_err_probe(dev, span,
> + if (ret < 0)
> + return dev_err_probe(dev, ret,
> "Failed to set span\n");
> + else
else is unnecessary here as we have the standard check and error and return
if set pattern.
> + chan->span = ret;
> }
>
> ret = fwnode_property_read_u32_array(child, "output-range-microamp",
> tmp, ARRAY_SIZE(tmp));
> if (!ret) {
> - chan->span = ltc2664_set_span(st, 0, tmp[1] / 1000, reg);
> - if (span < 0)
> - return dev_err_probe(dev, span,
> + ret = ltc2664_set_span(st, 0, tmp[1] / 1000, reg);
> + if (ret < 0)
> + return dev_err_probe(dev, ret,
> "Failed to set span\n");
> + else
and here.
> + chan->span = ret;
> }
> }
>
