6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
commit 752b6e3af374460a2de18f0c10bfa06bf844dbe8 upstream.
In mchp_core_pwm_apply_locked(), if hw_period_steps is equal to its max,
an error is reported and .apply fails. The max value is actually a
permitted value however, and so this check can fail where multiple
channels are enabled.
For example, the first channel to be configured requests a period that
sets hw_period_steps to the maximum value, and when a second channel
is enabled the driver reads hw_period_steps back from the hardware and
finds it to be the maximum possible value, triggering the warning on a
permitted value. The value to be avoided is 255 (PERIOD_STEPS_MAX + 1),
as that will produce undesired behaviour, so test for greater than,
rather than equal to.
Fixes: 2bf7ecf7b4ff ("pwm: add microchip soft ip corePWM driver")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20250122-pastor-fancied-0b993da2d2d2@spud
Signed-off-by: Uwe Kleine-König <ukleinek@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/pwm/pwm-microchip-core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/pwm/pwm-microchip-core.c
+++ b/drivers/pwm/pwm-microchip-core.c
@@ -327,7 +327,7 @@ static int mchp_core_pwm_apply_locked(st
* mchp_core_pwm_calc_period().
* The period is locked and we cannot change this, so we abort.
*/
- if (hw_period_steps == MCHPCOREPWM_PERIOD_STEPS_MAX)
+ if (hw_period_steps > MCHPCOREPWM_PERIOD_STEPS_MAX)
return -EINVAL;
prescale = hw_prescale;
