Re: [PATCH 7/8] backlight: lm3630a_bl: Remove invalid checks for unsigned int < 0

Daniel Thompson
2020-06-25T09:45:16Z

On Wed, Jun 24, 2020 at 03:57:20PM +0100, Lee Jones wrote:
> unsigned ints 'sources' and 'bank' cannot be less than LM3630A_SINK_0 (0)
> and LM3630A_BANK_0 (0) respecitively, so change the logic to only check
> for thier two possible valid values.
>
> Fixes W=1 warnings:
>
> drivers/video/backlight/lm3630a_bl.c: In function ‘lm3630a_parse_led_sources’:
> drivers/video/backlight/lm3630a_bl.c:394:18: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits]
> 394 | if (sources[i] < LM3630A_SINK_0 || sources[i] > LM3630A_SINK_1)
> | ^
> drivers/video/backlight/lm3630a_bl.c: In function ‘lm3630a_parse_bank’:
> drivers/video/backlight/lm3630a_bl.c:415:11: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits]
> 415 | if (bank < LM3630A_BANK_0 || bank > LM3630A_BANK_1)
> | ^
>
> Cc: <stable@vger.kernel.org>
> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
> Cc: Daniel Jeong <gshark.jeong@gmail.com>
> Cc: LDD MLP <ldd-mlp@list.ti.com>
> Signed-off-by: Lee Jones <lee.jones@linaro.org>

Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>

> ---
> drivers/video/backlight/lm3630a_bl.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/video/backlight/lm3630a_bl.c b/drivers/video/backlight/lm3630a_bl.c
> index ee320883b7108..e88a2b0e59046 100644
> --- a/drivers/video/backlight/lm3630a_bl.c
> +++ b/drivers/video/backlight/lm3630a_bl.c
> @@ -391,7 +391,7 @@ static int lm3630a_parse_led_sources(struct fwnode_handle *node,
> return ret;
>
> for (i = 0; i < num_sources; i++) {
> - if (sources[i] < LM3630A_SINK_0 || sources[i] > LM3630A_SINK_1)
> + if (sources[i] != LM3630A_SINK_0 && sources[i] != LM3630A_SINK_1)
> return -EINVAL;
>
> ret |= BIT(sources[i]);
> @@ -412,7 +412,7 @@ static int lm3630a_parse_bank(struct lm3630a_platform_data *pdata,
> if (ret)
> return ret;
>
> - if (bank < LM3630A_BANK_0 || bank > LM3630A_BANK_1)
> + if (bank != LM3630A_BANK_0 && bank != LM3630A_BANK_1)
> return -EINVAL;
>
> led_sources = lm3630a_parse_led_sources(node, BIT(bank));
> --
> 2.25.1
>