This is a note to let you know that I've just added the patch titled
pwm: lp3943: Fix duty calculation in case period was clamped
to the 5.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
pwm-lp3943-fix-duty-calculation-in-case-period-was-c.patch
and it can be found in the queue-5.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 9ebe10f1254b21a060fd72808b84d8b242c4d9e4
Author: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
Date: Fri Apr 8 17:22:38 2022 +0200
pwm: lp3943: Fix duty calculation in case period was clamped
[ Upstream commit 5e3b07ca5cc78cd4a987e78446849e41288d87cb ]
The hardware only supports periods <= 1.6 ms and if a bigger period is
requested it is clamped to 1.6 ms. In this case duty_cycle might be bigger
than 1.6 ms and then the duty cycle register is written with a value
bigger than LP3943_MAX_DUTY. So clamp duty_cycle accordingly.
Fixes: af66b3c0934e ("pwm: Add LP3943 PWM driver")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
Signed-off-by: Thierry Reding <thierry.reding@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/pwm/pwm-lp3943.c b/drivers/pwm/pwm-lp3943.c
index ea17d446a627..2bd04ecb508c 100644
--- a/drivers/pwm/pwm-lp3943.c
+++ b/drivers/pwm/pwm-lp3943.c
@@ -125,6 +125,7 @@ static int lp3943_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
if (err)
return err;
+ duty_ns = min(duty_ns, period_ns);
val = (u8)(duty_ns * LP3943_MAX_DUTY / period_ns);
return lp3943_write_byte(lp3943, reg_duty, val);
