Re: [PATCH] pwm: lpc18xx-sct: don't reconfigure PWM in .request and .free - Uwe Kleine-König

From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Vladimir Zapolskiy <vz@mleia.com>
Cc: linux-pwm@vger.kernel.org,
	Thierry Reding <thierry.reding@gmail.com>,
	linux-arm-kernel@lists.infradead.org, kernel@pengutronix.de
Subject: Re: [PATCH] pwm: lpc18xx-sct: don't reconfigure PWM in .request and .free
Date: Fri, 16 Nov 2018 10:48:02 +0100	[thread overview]
Message-ID: <20181116094802.5qpaygab5epnmwp5@pengutronix.de> (raw)
In-Reply-To: <1391bbe1-75b5-c86e-ed3a-1e1afb393917@mleia.com>

On Fri, Nov 16, 2018 at 11:22:49AM +0200, Vladimir Zapolskiy wrote:
> Hello Uwe,
> 
> On 11/16/2018 08:52 AM, Uwe Kleine-König wrote:
> > Regarding the .request case: The consumer might be interested in taking
> > over the configured state from the boot loader. So the initially
> > configured state should be retained.
> > 
> > For the free case the PWM consumer is responsible to disable the PWM
> > before calling pwm_release and there are three subcases to consider:
> > 
> 
> the changes are fine per se, but please split them into two.
> 
> Probably pwm_disable() misusage began spreading from commit 54b2a999a1675.

I see little benefit, but if that's the only problem I can split.

Note that the behaviours of .request and .free are not unrelated.
Currently because .free sets a duty cycle of 0 we have
pwm_get_duty_cycle always return 0 in .request.

Waiting on what Thierry thinks.

Best regards
Uwe

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Pengutronix e.K.                           | Uwe Kleine-König            |
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