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[24.155.109.49]) by smtp.gmail.com with ESMTPSA id o2sm8688151otj.2.2018.12.10.15.16.25 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 10 Dec 2018 15:16:25 -0800 (PST) Date: Mon, 10 Dec 2018 17:16:25 -0600 From: Rob Herring To: =?utf-8?B?Vm9rw6HEjQ==?= Michal Cc: Thierry Reding , Mark Rutland , "devicetree@vger.kernel.org" , "linux-pwm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Lukasz Majewski , Fabio Estevam , Lothar =?iso-8859-1?Q?Wa=DFmann?= , Linus Walleij , =?utf-8?B?Vm9rw6HEjQ==?= Michal Subject: Re: [RFC PATCH v3 1/2] dt-bindings: pwm: imx: Allow switching PWM output between PWM and GPIO Message-ID: <20181210231625.GA30721@bogus> References: <1544103655-104466-1-git-send-email-michal.vokac@ysoft.com> <1544103655-104466-2-git-send-email-michal.vokac@ysoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1544103655-104466-2-git-send-email-michal.vokac@ysoft.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 > --- > 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