linux-kernel - Re: [PATCH v2 4/6] pwm: omap-dmtimer: Fix pwm disabling sequence

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Date:   Fri, 13 Mar 2020 08:34:49 -0700
From:   Tony Lindgren <tony@...mide.com>
To:     Lokesh Vutla <lokeshvutla@...com>
Cc:     Thierry Reding <thierry.reding@...il.com>,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>,
        Linux OMAP Mailing List <linux-omap@...r.kernel.org>,
        linux-kernel@...r.kernel.org, linux-pwm@...r.kernel.org,
        Sekhar Nori <nsekhar@...com>, Vignesh R <vigneshr@...com>,
        Sebastian Reichel <sre@...nel.org>
Subject: Re: [PATCH v2 4/6] pwm: omap-dmtimer: Fix pwm disabling sequence

* Tony Lindgren <tony@...mide.com> [200312 00:59]:
> * Lokesh Vutla <lokeshvutla@...com> [200311 04:14]:
> > However, I see an issue with the patch itself as pm_runtime is not disabled
> > after the pwm is stopped. Not sure how that could be nullified with this approach.
> 
> Hmm yeah not sure what could be used to clear things
> when the current cycle is completed unless there's
> some interrupt for it.

You could enable pm_runtime_use_autosuspend() for pwm use,
then set the timeout to the cycle length, then in the
runtime_suspend make sure the enable bit is cleared if
requested.

But this too seems inaccurate, it would be best to clear
the enable bit on some cycle completion interrupt if
such thing is available.

Regards,

Tony