From: Thierry Reding <thierry.reding@gmail.com>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Fabrice Gasnier <fabrice.gasnier@st.com>,
jic23@kernel.org, robh+dt@kernel.org, mark.rutland@arm.com,
alexandre.torgue@st.com, mcoquelin.stm32@gmail.com,
linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org,
vilhelm.gray@gmail.com, linux-stm32@st-md-mailman.stormreply.com,
Tomasz Duszynski <tduszyns@gmail.com>
Subject: Re: [PATCH 2/4] pwm: stm32-lp: Add power management support
Date: Wed, 6 Feb 2019 13:55:45 +0100 [thread overview]
Message-ID: <20190206125545.GI21676@ulmo> (raw)
In-Reply-To: <20190206085405.pdiwd3c6wjog5hl7@pengutronix.de>
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On Wed, Feb 06, 2019 at 09:54:05AM +0100, Uwe Kleine-König wrote:
> On Wed, Feb 06, 2019 at 09:42:48AM +0100, Fabrice Gasnier wrote:
> > If you agree with the current approach, I can send a V2 with Tomasz's
> > suggestion to remove the ifdefs and use __maybe_unused instead.
>
> I think the suspend callback should have something like:
>
> if (is_still_enabled) {
> /*
> * The consumer didn't stop us, so refuse to suspend.
> */
> dev_err(dev, "The consumer didn't stop us, so refuse to suspend.\n");
> return -EBUSY;
> }
>
> This way there are no bad surprises if the pwm is suspended before its
> consumer and it's obvious what is missing.
Something that just occurred to me: perhaps as part of pwm_get() we
should track where we were being requested from so that we could give
hints in situations like this as to where the consumer is that forgot
to suspend the PWM.
I suppose we already have pwm_device.label to help with this, but
perhaps we could improve things if we stored __builtin_return_address
during pwm_get() to help users pinpoint where they need to look.
Thierry
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next prev parent reply other threads:[~2019-02-06 12:55 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-05 12:40 [PATCH 0/4] Add PM support to STM32 LP Timer drivers Fabrice Gasnier
2019-02-05 12:40 ` [PATCH 1/4] dt-bindings: pwm-stm32-lp: document pinctrl sleep state Fabrice Gasnier
2019-02-05 12:40 ` [PATCH 2/4] pwm: stm32-lp: Add power management support Fabrice Gasnier
2019-02-05 18:30 ` Tomasz Duszynski
2019-02-06 8:42 ` Fabrice Gasnier
2019-02-05 20:47 ` Uwe Kleine-König
2019-02-05 22:25 ` Thierry Reding
2019-02-06 8:42 ` Fabrice Gasnier
2019-02-06 8:54 ` Uwe Kleine-König
2019-02-06 12:55 ` Thierry Reding [this message]
2019-02-06 14:54 ` Fabrice Gasnier
2019-02-05 12:40 ` [PATCH 3/4] dt-bindings: iio: stm32-lptimer-counter: document pinctrl sleep state Fabrice Gasnier
2019-02-05 12:40 ` [PATCH 4/4] iio: counter: stm32-lptimer: Add power management support Fabrice Gasnier
2019-02-09 16:21 ` Jonathan Cameron
2019-02-10 21:33 ` Uwe Kleine-König
2019-02-11 13:21 ` Fabrice Gasnier
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