From: Rob Herring <robh@kernel.org>
To: "Vokáč Michal" <Michal.Vokac@ysoft.com>
Cc: "Thierry Reding" <thierry.reding@gmail.com>,
"Mark Rutland" <mark.rutland@arm.com>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-pwm@vger.kernel.org" <linux-pwm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Lukasz Majewski" <l.majewski@majess.pl>,
"Fabio Estevam" <fabio.estevam@nxp.com>,
"Lothar Waßmann" <LW@karo-electronics.de>,
"Linus Walleij" <linus.walleij@linaro.org>,
"Vokáč Michal" <Michal.Vokac@ysoft.com>
Subject: Re: [RFC PATCH v3 1/2] dt-bindings: pwm: imx: Allow switching PWM output between PWM and GPIO
Date: Mon, 10 Dec 2018 17:16:25 -0600 [thread overview]
Message-ID: <20181210231625.GA30721@bogus> (raw)
In-Reply-To: <1544103655-104466-2-git-send-email-michal.vokac@ysoft.com>
On Thu, 6 Dec 2018 13:41:30 +0000, =?utf-8?B?Vm9rw6HEjSBNaWNoYWw=?= wrote:
> Output of the PWM block on i.MX SoCs is always low when the block is
> disabled. This can cause issues when inverted PWM polarity is needed.
> With inverted polarity a duty cycle = 0% corresponds to high level on
> the output. Now, when PWM is disabled its output instantly goes low
> which corresponds to duty cycle = 100%.
>
> To get a truly inverted PWM output two pinctrl states of the PWM pin
> can be used. Configure the pin to GPIO function when PWM is disabled
> and switch back to PWM function whenever non-zero duty cycle is needed.
>
> Signed-off-by: Michal Vokáč <michal.vokac@ysoft.com>
> ---
> Changes in v3:
> - Slightly different description of the pinctrl and pwm-gpio.
>
> Changes in v2:
> - Do not use the "default" pinctrl state for GPIO.
> - Use two new "pwm" and "gpio" pinctrl states.
> - Add a new pwm-gpios signal.
>
> Documentation/devicetree/bindings/pwm/imx-pwm.txt | 49 +++++++++++++++++++++++
> 1 file changed, 49 insertions(+)
>
Reviewed-by: Rob Herring <robh@kernel.org>
next prev parent reply other threads:[~2018-12-10 23:16 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-06 13:41 [RFC PATCH v3 0/2] pwm: imx: Configure output to GPIO in disabled state Vokáč Michal
2018-12-06 13:41 ` [RFC PATCH v3 1/2] dt-bindings: pwm: imx: Allow switching PWM output between PWM and GPIO Vokáč Michal
2018-12-10 23:16 ` Rob Herring [this message]
2018-12-14 13:45 ` Linus Walleij
2018-12-06 13:41 ` [RFC PATCH v3 2/2] pwm: imx: Configure output to GPIO in disabled state Vokáč Michal
2018-12-06 13:59 ` Uwe Kleine-König
2018-12-06 15:37 ` Vokáč Michal
2018-12-06 16:16 ` Uwe Kleine-König
2018-12-10 11:15 ` Vokáč Michal
2018-12-10 11:17 ` Uwe Kleine-König
2018-12-10 11:38 ` Vokáč Michal
2018-12-12 8:01 ` Uwe Kleine-König
2018-12-12 11:42 ` Vokáč Michal
2018-12-12 12:12 ` Uwe Kleine-König
2019-01-24 8:59 ` Michal Vokáč
2019-01-24 9:22 ` Uwe Kleine-König
2019-01-24 10:12 ` Michal Vokáč
2019-01-24 10:44 ` Uwe Kleine-König
2019-01-30 14:42 ` Michal Vokáč
2019-01-30 15:39 ` Uwe Kleine-König
2019-02-01 15:50 ` Michal Vokáč
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