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leds: lp55xx: Fix check for invalid channel number

Message ID 1728464547-31722-1-git-send-email-michal.vokac@ysoft.com
State New
Headers show
Series leds: lp55xx: Fix check for invalid channel number | expand

Commit Message

Michal Vokáč Oct. 9, 2024, 9:02 a.m. UTC
Prior to commit 92a81562e695 ("leds: lp55xx: Add multicolor framework
support to lp55xx") the reg property (chan_nr) was parsed and stored
as it was. Then, in lp55xx_init_led() function, it was checked if it
is within valid range. In case it was not, an error message was
printed and the driver probe failed.

With the mentioned commit the reg property is checked right after it
is read from the device tree. Comparison to the upper range is not
correct though. Valid reg values are 0 to (max_channel - 1). So in
case the parsed value is out of this (wrong) range the probe just
fails and no error message is shown.

Fix it by using proper comparison and print a message in case of
an error. The check that is done in lp55xx_init_led() function is now
redundant and can be removed.

Fixes: 92a81562e695 ("leds: lp55xx: Add multicolor framework support to lp55xx")
Cc: <stable@vger.kernel.org>
Signed-off-by: Michal Vokáč <michal.vokac@ysoft.com>
---
 drivers/leds/leds-lp55xx-common.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

Comments

Michal Vokáč Oct. 10, 2024, 7:16 a.m. UTC | #1
On 10. 10. 24 8:00, kernel test robot wrote:

> vim +1130 drivers/leds/leds-lp55xx-common.c
> 
>    1111	
>    1112	static int lp55xx_parse_common_child(struct device_node *np,
>    1113					     struct lp55xx_led_config *cfg,
>    1114					     int led_number, int *chan_nr)
>    1115	{
>    1116		int ret;
>    1117	
>    1118		of_property_read_string(np, "chan-name",
>    1119					&cfg[led_number].name);
>    1120		of_property_read_u8(np, "led-cur",
>    1121				    &cfg[led_number].led_current);
>    1122		of_property_read_u8(np, "max-cur",
>    1123				    &cfg[led_number].max_current);
>    1124	
>    1125		ret = of_property_read_u32(np, "reg", chan_nr);
>    1126		if (ret)
>    1127			return ret;
>    1128	
>    1129		if (*chan_nr < 0 || *chan_nr >= cfg->max_channel) {
>> 1130			dev_err(dev, "Use channel numbers between 0 and %d\n",

Ahh, rookie mistake. Of course the dev is not available here. I feel dumb
as I think I at least compile tested this..

Anyway, the comparison is wrong and I still think it is not nice to
the user/DT developer to quietly fail here. I suggest to remove this
check here completely and keep the one in the lp55xx_init_led().

Michal

>    1131				cfg->max_channel - 1);
>    1132			return -EINVAL;
>    1133		}
>    1134	
>    1135		return 0;
>    1136	}
>    1137	
>
diff mbox series

Patch

diff --git a/drivers/leds/leds-lp55xx-common.c b/drivers/leds/leds-lp55xx-common.c
index 5a2e259679cf..055ee77455f9 100644
--- a/drivers/leds/leds-lp55xx-common.c
+++ b/drivers/leds/leds-lp55xx-common.c
@@ -512,12 +512,6 @@  static int lp55xx_init_led(struct lp55xx_led *led,
 	led->max_current = pdata->led_config[chan].max_current;
 	led->chan_nr = pdata->led_config[chan].chan_nr;
 
-	if (led->chan_nr >= max_channel) {
-		dev_err(dev, "Use channel numbers between 0 and %d\n",
-			max_channel - 1);
-		return -EINVAL;
-	}
-
 	if (pdata->led_config[chan].num_colors > 1)
 		ret = devm_led_classdev_multicolor_register(dev, &led->mc_cdev);
 	else
@@ -1132,8 +1126,11 @@  static int lp55xx_parse_common_child(struct device_node *np,
 	if (ret)
 		return ret;
 
-	if (*chan_nr < 0 || *chan_nr > cfg->max_channel)
+	if (*chan_nr < 0 || *chan_nr >= cfg->max_channel) {
+		dev_err(dev, "Use channel numbers between 0 and %d\n",
+			cfg->max_channel - 1);
 		return -EINVAL;
+	}
 
 	return 0;
 }