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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Hans de Goede <hdegoede@redhat.com>
Cc: "Thierry Reding" <thierry.reding@gmail.com>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	"Jani Nikula" <jani.nikula@linux.intel.com>,
	"Joonas Lahtinen" <joonas.lahtinen@linux.intel.com>,
	"Rodrigo Vivi" <rodrigo.vivi@intel.com>,
	"Ville Syrjälä" <ville.syrjala@linux.intel.com>,
	"Rafael J . Wysocki" <rjw@rjwysocki.net>,
	"Len Brown" <lenb@kernel.org>,
	linux-pwm@vger.kernel.org,
	intel-gfx <intel-gfx@lists.freedesktop.org>,
	dri-devel@lists.freedesktop.org,
	"Mika Westerberg" <mika.westerberg@linux.intel.com>,
	linux-acpi@vger.kernel.org
Subject: Re: [PATCH v5 06/16] pwm: lpss: Use pwm_lpss_apply() when restoring state on resume
Date: Wed, 29 Jul 2020 11:12:18 +0300
Message-ID: <20200729081218.GH3703480@smile.fi.intel.com> (raw)
In-Reply-To: <1e19e31f-cf68-5607-3027-3b963ce53c39@redhat.com>

On Tue, Jul 28, 2020 at 09:55:22PM +0200, Hans de Goede wrote:
> On 7/28/20 8:57 PM, Andy Shevchenko wrote:
> > On Fri, Jul 17, 2020 at 03:37:43PM +0200, Hans de Goede wrote:

...

> > Maybe I'm too picky, but I would go even further and split apply to two versions
> > 
> > static int pwm_lpss_apply_on_resume(struct pwm_chip *chip, struct pwm_device *pwm,
> > 			  const struct pwm_state *state)
> > >   {
> > >   	struct pwm_lpss_chip *lpwm = to_lpwm(chip);
> > >   	if (state->enabled)
> > >   		return pwm_lpss_prepare_enable(lpwm, pwm, state, !pwm_is_enabled(pwm));
> > >   	if (pwm_is_enabled(pwm)) {
> > >   		pwm_lpss_write(pwm, pwm_lpss_read(pwm) & ~PWM_ENABLE);
> > >   	return 0;
> > >   }
> > 
> > and another one for !from_resume.
> 
> It is a bit picky :) But that is actually not a bad idea, although I would write
> it like this for more symmetry with the normal (not on_resume) apply version,
> while at it I also renamed the function:
> 
> /*
>  * This is a mirror of pwm_lpss_apply() without pm_runtime reference handling
>  * for restoring the PWM state on resume.
>  */
> static int pwm_lpss_restore_state(struct pwm_chip *chip, struct pwm_device *pwm,
>                                   const struct pwm_state *state)
> {
>    	struct pwm_lpss_chip *lpwm = to_lpwm(chip);
> 	int ret = 0;
> 
>    	if (state->enabled)
>    		ret = pwm_lpss_prepare_enable(lpwm, pwm, state, !pwm_is_enabled(pwm));
>    	else if (pwm_is_enabled(pwm))
>    		pwm_lpss_write(pwm, pwm_lpss_read(pwm) & ~PWM_ENABLE);
> 
>    	return ret;
> }
> 
> Would that work for you?

Yes.

...

> > > +		ret = __pwm_lpss_apply(&lpwm->chip, pwm, &saved_state, true);
> > > +		if (ret)
> > > +			dev_err(dev, "Error restoring state on resume\n");
> > 
> > I'm wondering if it's a real error why we do not bail out?
> > Otherwise dev_warn() ?
> 
> It is a real error, but a single PWM chip might have multiple controllers
> and bailing out early would mean not even trying to restore the state on
> the other controllers.  As for propagating the error, AFAIK the pm framework
> does not do anything with resume errors other then log an extra error.

OK.

-- 
With Best Regards,
Andy Shevchenko



  reply index

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-17 13:37 [PATCH v5 00/16] acpi/pwm/i915: Convert pwm-crc and i915 driver's PWM code to use the atomic PWM API Hans de Goede
2020-07-17 13:37 ` [PATCH v5 01/16] ACPI / LPSS: Resume Cherry Trail PWM controller in no-irq phase Hans de Goede
2020-07-17 13:37 ` [PATCH v5 02/16] ACPI / LPSS: Save Cherry Trail PWM ctx registers only once (at activation) Hans de Goede
2020-07-17 13:37 ` [PATCH v5 03/16] pwm: lpss: Fix off by one error in base_unit math in pwm_lpss_prepare() Hans de Goede
2020-07-17 13:37 ` [PATCH v5 04/16] pwm: lpss: Add range limit check for the base_unit register value Hans de Goede
2020-07-17 13:37 ` [PATCH v5 05/16] pwm: lpss: Add pwm_lpss_prepare_enable() helper Hans de Goede
2020-07-28 18:45   ` Andy Shevchenko
2020-07-28 19:49     ` Hans de Goede
2020-07-17 13:37 ` [PATCH v5 06/16] pwm: lpss: Use pwm_lpss_apply() when restoring state on resume Hans de Goede
2020-07-28 18:57   ` Andy Shevchenko
2020-07-28 19:55     ` Hans de Goede
2020-07-29  8:12       ` Andy Shevchenko [this message]
2020-08-02 20:51         ` Hans de Goede
2020-08-03  8:41           ` Andy Shevchenko
2020-07-17 13:37 ` [PATCH v5 07/16] pwm: crc: Fix period / duty_cycle times being off by a factor of 256 Hans de Goede
2020-07-28 19:36   ` Andy Shevchenko
2020-07-28 20:00     ` Hans de Goede
2020-07-29  8:13   ` Andy Shevchenko
2020-07-17 13:37 ` [PATCH v5 08/16] pwm: crc: Fix off-by-one error in the clock-divider calculations Hans de Goede
2020-07-29 10:28   ` Andy Shevchenko
2020-07-17 13:37 ` [PATCH v5 09/16] pwm: crc: Fix period changes not having any effect Hans de Goede
2020-07-29 10:30   ` Andy Shevchenko
2020-07-17 13:37 ` [PATCH v5 10/16] pwm: crc: Enable/disable PWM output on enable/disable Hans de Goede
2020-07-29 10:32   ` Andy Shevchenko
2020-07-17 13:37 ` [PATCH v5 11/16] pwm: crc: Implement apply() method to support the new atomic PWM API Hans de Goede
2020-07-29 10:51   ` Andy Shevchenko
2020-07-17 13:37 ` [PATCH v5 12/16] pwm: crc: Implement get_state() method Hans de Goede
2020-07-17 13:37 ` [PATCH v5 13/16] drm/i915: panel: Add get_vbt_pwm_freq() helper Hans de Goede
2020-07-17 13:37 ` [PATCH v5 14/16] drm/i915: panel: Honor the VBT PWM frequency for devs with an external PWM controller Hans de Goede
2020-07-17 13:44 ` [PATCH v5 15/16] drm/i915: panel: Honor the VBT PWM min setting " Hans de Goede
2020-07-17 13:44   ` [PATCH v5 16/16] drm/i915: panel: Use atomic PWM API " Hans de Goede
2020-07-27  7:41 ` [PATCH v5 00/16] acpi/pwm/i915: Convert pwm-crc and i915 driver's PWM code to use the atomic PWM API Thierry Reding
2020-07-29  8:23   ` Andy Shevchenko
2020-07-29  9:32     ` Hans de Goede
2020-07-30  9:26       ` Thierry Reding
2020-08-01 14:33         ` Hans de Goede
2020-07-29 10:54 ` Andy Shevchenko
2020-08-01 14:38   ` Hans de Goede
2020-08-02 11:25     ` Andy Shevchenko
2020-08-02 19:43       ` Hans de Goede

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