From: Conor Dooley conor.dooley@microchip.com

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 --- CC: Conor Dooley conor.dooley@microchip.com CC: Daire McNamara daire.mcnamara@microchip.com CC: Uwe Kleine-König ukleinek@kernel.org CC: Thierry Reding thierry.reding@gmail.com CC: linux-riscv@lists.infradead.org CC: linux-pwm@vger.kernel.org CC: linux-kernel@vger.kernel.org --- drivers/pwm/pwm-microchip-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-microchip-core.c b/drivers/pwm/pwm-microchip-core.c index c1f2287b8e97..12821b4bbf97 100644 --- 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(struct pwm_chip *chip, struct pwm_device * * 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;