linux-kernel - Re: [PATCH v4] pwm: tiehrpwm: Enable pwmchip's parent device before setting configuration

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Message-ID: <3ck3abtfdqzmatsvfqcbp7bxu7ydy7u37hfkke4xvpatpcg5uk@wfnya5hxrplo>
Date: Wed, 21 Jan 2026 11:18:22 +0100
From: Uwe Kleine-König <ukleinek@...nel.org>
To: Gokul Praveen <g-praveen@...com>
Cc: j-keerthy@...com, linux-pwm@...r.kernel.org, 
	linux-kernel@...r.kernel.org, u-kumar1@...com, n-francis@...com
Subject: Re: [PATCH v4] pwm: tiehrpwm: Enable pwmchip's parent device before
 setting  configuration

Hello Gokul,

On Wed, Jan 21, 2026 at 11:41:34AM +0530, Gokul Praveen wrote:
> The period and duty cycle configurations on J7200 and J784S4 SoCs
> does not get reflected after setting them using sysfs nodes.
> This is because at the end of ehrpwm_pwm_config function,
> the put_sync function is called which resets the hardware.
> 
> Hold the PWM controller out of low-power mode during .apply() to
> make sure it accepts the writes to its registers.
> 
> This renders the calls to pm_runtime_get_sync() and
> pm_runtime_put_sync() in ehrpwm_pwm_config() into no-ops, so
> these can be dropped.
> 
> Fixes: 5f027d9b83db("pwm: tiehrpwm: Implement .apply() callback")
> Signed-off-by: Gokul Praveen <g-praveen@...com>

I applied this patch to

	https://git.kernel.org/pub/scm/linux/kernel/git/ukleinek/linux.git pwm/for-next

and will send it during the next merge window. The problem is old
(v5.18-rc1~54^2~29 from 2021) and it's late in the development cycle, so
I won't bother Linus with it for 6.19.

Best regards
Uwe

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