6.6-stable review patch. If anyone has any objections, please let me know.
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From: Conor Dooley conor.dooley@microchip.com
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@vger.kernel.org Signed-off-by: Conor Dooley conor.dooley@microchip.com Link: https://lore.kernel.org/r/20250122-pastor-fancied-0b993da2d2d2@spud Signed-off-by: Uwe Kleine-König ukleinek@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 @@ -328,7 +328,7 @@ 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;