The ARR (auto reload register) and CMP (compare) registers are
successively written. The status bits to check the update of these
registers are polled together with regmap_read_poll_timeout().
The condition to end the loop may become true, even if one of the
register isn't correctly updated.
So ensure both status bits are set before clearing them.
Fixes: e70a540b4e02 ("pwm: Add STM32 LPTimer PWM driver")
Signed-off-by: Fabrice Gasnier <[email protected]>
---
drivers/pwm/pwm-stm32-lp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pwm/pwm-stm32-lp.c b/drivers/pwm/pwm-stm32-lp.c
index 3115abb3f52a..61a1c87cd501 100644
--- a/drivers/pwm/pwm-stm32-lp.c
+++ b/drivers/pwm/pwm-stm32-lp.c
@@ -127,7 +127,7 @@ static int stm32_pwm_lp_apply(struct pwm_chip *chip, struct pwm_device *pwm,
/* ensure CMP & ARR registers are properly written */
ret = regmap_read_poll_timeout(priv->regmap, STM32_LPTIM_ISR, val,
- (val & STM32_LPTIM_CMPOK_ARROK),
+ (val & STM32_LPTIM_CMPOK_ARROK) == STM32_LPTIM_CMPOK_ARROK,
100, 1000);
if (ret) {
dev_err(priv->chip.dev, "ARR/CMP registers write issue\n");
--
2.25.1
On Wed, Nov 23, 2022 at 02:36:52PM +0100, Fabrice Gasnier wrote:
> The ARR (auto reload register) and CMP (compare) registers are
> successively written. The status bits to check the update of these
> registers are polled together with regmap_read_poll_timeout().
> The condition to end the loop may become true, even if one of the
> register isn't correctly updated.
> So ensure both status bits are set before clearing them.
>
> Fixes: e70a540b4e02 ("pwm: Add STM32 LPTimer PWM driver")
> Signed-off-by: Fabrice Gasnier <[email protected]>
Looks reasonable
Acked-by: Uwe Kleine-K?nig <[email protected]>
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-K?nig |
Industrial Linux Solutions | https://www.pengutronix.de/ |
On Wed, 23 Nov 2022 14:36:52 +0100, Fabrice Gasnier wrote:
> The ARR (auto reload register) and CMP (compare) registers are
> successively written. The status bits to check the update of these
> registers are polled together with regmap_read_poll_timeout().
> The condition to end the loop may become true, even if one of the
> register isn't correctly updated.
> So ensure both status bits are set before clearing them.
>
> [...]
Applied, thanks!
[1/1] pwm: stm32-lp: fix the check on arr and cmp registers update
commit: 3066bc2d58be31275afb51a589668f265e419c37
Best regards,
--
Thierry Reding <[email protected]>