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

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Message-ID: <d773qlfhifbtn6xtkuowdu3l3h6em7hrk2etsg3n5umuiuhfu7@yuetzfci7pni>
Date: Fri, 23 Jan 2026 19:01:38 +0100
From: Uwe Kleine-König <ukleinek@...nel.org>
To: "Kumar, Udit" <u-kumar1@...com>
Cc: Gokul Praveen <g-praveen@...com>, j-keerthy@...com, 
	linux-pwm@...r.kernel.org, linux-kernel@...r.kernel.org, n-francis@...com
Subject: Re: [PATCH v4] pwm: tiehrpwm: Enable pwmchip's parent device before
 setting configuration

Hello,

On Fri, Jan 23, 2026 at 08:28:48PM +0530, Kumar, Udit wrote:
> On 1/21/2026 4:19 PM, Gokul Praveen wrote:
> > Hello Uwe,
> > 
> > On 21/01/26 15:48, Uwe Kleine-König wrote:
> > > 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.
> > > 
> > 
> fyi,
> 
> We are hitting compilation error with this patch
> 
> https://gist.github.com/uditkumarti/d23bc9ee1886bfce70cc76e4b19fbb59

I assume you tried to compile this patch on top of a tree that doesn't
also has commit 9a0abc39450a3123fd52533a662fbd37e0d1508c?

Best regards
Uwe

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