* [PATCH] leds: mt6323: move period calculation
@ 2020-08-09 16:32 trix
2020-08-09 22:33 ` Pavel Machek
0 siblings, 1 reply; 2+ messages in thread
From: trix @ 2020-08-09 16:32 UTC (permalink / raw)
To: sean.wang, pavel, dmurphy, matthias.bgg, jacek.anaszewski
Cc: linux-leds, linux-arm-kernel, linux-mediatek, linux-kernel, Tom Rix
From: Tom Rix <trix@redhat.com>
clang static analysis reports this problem
leds-mt6323.c:275:12: warning: Division by zero
duty_hw = MT6323_CAL_HW_DUTY(*delay_on, period);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This is because period can be 0.
period = *delay_on + *delay_off;
There is a later check that *delay_on/off are valid.
if (!*delay_on && !*delay_off) {
*delay_on = 500;
*delay_off = 500;
}
Setting the delay_on/off means period needs to be recalculated
anyway. So move the period statements after this check.
Fixes: 216ec6cc4c19 ("leds: Add LED support for MT6323 PMIC")
Signed-off-by: Tom Rix <trix@redhat.com>
---
drivers/leds/leds-mt6323.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/leds/leds-mt6323.c b/drivers/leds/leds-mt6323.c
index 2a13e3161bf4..7b240771e45b 100644
--- a/drivers/leds/leds-mt6323.c
+++ b/drivers/leds/leds-mt6323.c
@@ -248,15 +248,6 @@ static int mt6323_led_set_blink(struct led_classdev *cdev,
u8 duty_hw;
int ret;
- /*
- * Units are in ms, if over the hardware able
- * to support, fallback into software blink
- */
- period = *delay_on + *delay_off;
-
- if (period > MT6323_MAX_PERIOD)
- return -EINVAL;
-
/*
* LED subsystem requires a default user
* friendly blink pattern for the LED so using
@@ -268,6 +259,15 @@ static int mt6323_led_set_blink(struct led_classdev *cdev,
*delay_off = 500;
}
+ /*
+ * Units are in ms, if over the hardware able
+ * to support, fallback into software blink
+ */
+ period = *delay_on + *delay_off;
+
+ if (period > MT6323_MAX_PERIOD)
+ return -EINVAL;
+
/*
* Calculate duty_hw based on the percentage of period during
* which the led is ON.
--
2.18.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] leds: mt6323: move period calculation
2020-08-09 16:32 [PATCH] leds: mt6323: move period calculation trix
@ 2020-08-09 22:33 ` Pavel Machek
0 siblings, 0 replies; 2+ messages in thread
From: Pavel Machek @ 2020-08-09 22:33 UTC (permalink / raw)
To: trix
Cc: sean.wang, dmurphy, matthias.bgg, jacek.anaszewski, linux-leds,
linux-arm-kernel, linux-mediatek, linux-kernel
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Hi!
> Setting the delay_on/off means period needs to be recalculated
> anyway. So move the period statements after this check.
>
> Fixes: 216ec6cc4c19 ("leds: Add LED support for MT6323 PMIC")
Makes sense, thanks, applied.
Best regards,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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