[PATCH v2] pwm: berlin: Fix wrong register in suspend/resume

[PATCH v2] pwm: berlin: Fix wrong register in suspend/resume

[Jisheng Zhang]

The 'enable' register should be BERLIN_PWM_EN rather than
BERLIN_PWM_ENABLE, otherwise, the driver accesses wrong address, there
will be cpu exception then kernel panic during suspend/resume.

Fixes: bbf0722c1c66 ("pwm: berlin: Add suspend/resume support")
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
since v1:
 - update commit log to mention cpu exception then kernel panic w/o
   the patch

 drivers/pwm/pwm-berlin.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/pwm/pwm-berlin.c b/drivers/pwm/pwm-berlin.c
index 831aed228caf..858d36991374 100644
--- a/drivers/pwm/pwm-berlin.c
+++ b/drivers/pwm/pwm-berlin.c
@@ -234,7 +234,7 @@ static int berlin_pwm_suspend(struct device *dev)
 	for (i = 0; i < chip->npwm; i++) {
 		struct berlin_pwm_channel *channel = &bpc->channel[i];
 
-		channel->enable = berlin_pwm_readl(bpc, i, BERLIN_PWM_ENABLE);
+		channel->enable = berlin_pwm_readl(bpc, i, BERLIN_PWM_EN);
 		channel->ctrl = berlin_pwm_readl(bpc, i, BERLIN_PWM_CONTROL);
 		channel->duty = berlin_pwm_readl(bpc, i, BERLIN_PWM_DUTY);
 		channel->tcnt = berlin_pwm_readl(bpc, i, BERLIN_PWM_TCNT);
@@ -262,7 +262,7 @@ static int berlin_pwm_resume(struct device *dev)
 		berlin_pwm_writel(bpc, i, channel->ctrl, BERLIN_PWM_CONTROL);
 		berlin_pwm_writel(bpc, i, channel->duty, BERLIN_PWM_DUTY);
 		berlin_pwm_writel(bpc, i, channel->tcnt, BERLIN_PWM_TCNT);
-		berlin_pwm_writel(bpc, i, channel->enable, BERLIN_PWM_ENABLE);
+		berlin_pwm_writel(bpc, i, channel->enable, BERLIN_PWM_EN);
 	}
 
 	return 0;
-- 
2.50.0

Re: [PATCH v2] pwm: berlin: Fix wrong register in suspend/resume

[Uwe Kleine-König]

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Hello,

On Tue, Aug 19, 2025 at 07:42:24PM +0800, Jisheng Zhang wrote:
> The 'enable' register should be BERLIN_PWM_EN rather than
> BERLIN_PWM_ENABLE, otherwise, the driver accesses wrong address, there
> will be cpu exception then kernel panic during suspend/resume.
> 
> Fixes: bbf0722c1c66 ("pwm: berlin: Add suspend/resume support")
> Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> ---
> since v1:
>  - update commit log to mention cpu exception then kernel panic w/o
>    the patch

Applied this patch to

https://git.kernel.org/pub/scm/linux/kernel/git/ukleinek/linux.git pwm/fixes

with a Cc: stable now. Given this issue is nearly 9 years old I'm not
sure yet this fix is urgent enough to justify a fixes PR to Linus.

However there are two such patches now, so maybe I will prepare another
pull request before 6.17. But for now I will give it a few days in next
first.

Best regards
Uwe

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