linux-kernel - Re: [PATCH v4 1/1] pwm: pca9685: fix gpio-only operation.

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Date:   Thu, 13 Apr 2017 17:34:16 +0200
From:   Thierry Reding <thierry.reding@...il.com>
To:     Sven Van Asbroeck <thesven73@...il.com>
Cc:     linux-pwm@...r.kernel.org, linux-kernel@...r.kernel.org,
        clemens.gruber@...ruber.com, mika.westerberg@...ux.intel.com,
        andriy.shevchenko@...ux.intel.com,
        Sven Van Asbroeck <TheSven73@...glemail.com>
Subject: Re: [PATCH v4 1/1] pwm: pca9685: fix gpio-only operation.

On Thu, Apr 13, 2017 at 08:58:11AM -0400, Sven Van Asbroeck wrote:
> gpio-only driver operation never clears the SLEEP bit, which can
> cause the gpios to become unusable.
> 
> Example:
> 1. user requests first pwm  ->      driver clears SLEEP bit
> 2. user frees last pwm      ->      driver sets SLEEP bit
> 3. user requests gpio
> 4. user switches gpio on    ->      output does not turn on
>                                     because SLEEP bit is set
> 
> Prevent this behaviour by letting the runtime_pm framework
> control the SLEEP bit. This will put the chip to SLEEP if
> no pwms/gpios are exported/in use.
> 
> Fixes: bccec89f0a35 ("Allow any of the 16 PWMs to be used as a GPIO")
> Reported-by: Sven Van Asbroeck <TheSven73@...glemail.com>
> Signed-off-by: Sven Van Asbroeck <TheSven73@...glemail.com>
> Suggested-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
> Reviewed-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
> ---
>  drivers/pwm/pwm-pca9685.c | 112 ++++++++++++++++++++++++++++++++--------------
>  1 file changed, 79 insertions(+), 33 deletions(-)

Applied with s/gpio/GPIO/ and s/pwm/PWM/.

Thanks,
Thierry

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