From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: "Jonathan Neuschäfer" <j.neuschaefer@gmx.net>
Cc: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Alexandre Belloni" <alexandre.belloni@bootlin.com>,
"Heiko Stuebner" <heiko@sntech.de>,
devicetree <devicetree@vger.kernel.org>,
"Linus Walleij" <linus.walleij@linaro.org>,
"Thierry Reding" <thierry.reding@gmail.com>,
"Sam Ravnborg" <sam@ravnborg.org>,
"open list:REAL TIME CLOCK (RTC) SUBSYSTEM"
<linux-rtc@vger.kernel.org>, "Arnd Bergmann" <arnd@arndb.de>,
"Mauro Carvalho Chehab" <mchehab+huawei@kernel.org>,
"Fabio Estevam" <festevam@gmail.com>,
"Daniel Palmer" <daniel@0x0f.com>,
"Andreas Kemnade" <andreas@kemnade.info>,
"NXP Linux Team" <linux-imx@nxp.com>,
linux-pwm@vger.kernel.org,
"Stephan Gerhold" <stephan@gerhold.net>,
allen <allen.chen@ite.com.tw>,
"Sascha Hauer" <s.hauer@pengutronix.de>,
"Lubomir Rintel" <lkundrak@v3.sk>,
"Rob Herring" <robh+dt@kernel.org>,
"Lee Jones" <lee.jones@linaro.org>,
"linux-arm Mailing List" <linux-arm-kernel@lists.infradead.org>,
"Alessandro Zummo" <a.zummo@towertech.it>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
"Mark Brown" <broonie@kernel.org>,
"Pengutronix Kernel Team" <kernel@pengutronix.de>,
"Heiko Stuebner" <heiko.stuebner@theobroma-systems.com>,
"Josua Mayer" <josua.mayer@jm0.eu>,
"Shawn Guo" <shawnguo@kernel.org>,
"David S. Miller" <davem@davemloft.net>
Subject: Re: [PATCH v3 4/7] pwm: ntxec: Add driver for PWM function in Netronix EC
Date: Sat, 3 Oct 2020 11:17:58 +0300 [thread overview]
Message-ID: <CAHp75VeSB4i_QNOX1UbrooNo0twqgbOhoaxnwk5a+=dEFWMzqA@mail.gmail.com> (raw)
In-Reply-To: <20201002233630.GB500800@latitude>
On Sat, Oct 3, 2020 at 2:36 AM Jonathan Neuschäfer
<j.neuschaefer@gmx.net> wrote:
> On Mon, Sep 28, 2020 at 10:35:46AM +0200, Uwe Kleine-König wrote:
> > On Sun, Sep 27, 2020 at 11:10:44PM +0200, Jonathan Neuschäfer wrote:
...
> > You can even check this with an LED using something like:
> >
> > pwm_apply(mypwm, {.enabled = true, .duty_cycle = $big, .period = $big});
> > pwm_apply(mypwm, {.enabled = false, ... });
> >
> > . If the period is completed the LED is on for $big ns, if not the LED
> > is on for a timespan that is probably hardly noticable with the human
> > eye.
>
> The longest configurable period is about 8ms, so it's not long enough to
> see anything. However, after writing enable=0, it can take about a
> second for the PWM signal to turn off... this hardware is a bit weird.
Sounds like you have 1/128 divisor and off/on is done on lower
frequency. (We saw PWMs with an additional 7-bit counter, reminds me
Crystal Cove PMIC PWM).
--
With Best Regards,
Andy Shevchenko
WARNING: multiple messages have this Message-ID (diff)
From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: "Jonathan Neuschäfer" <j.neuschaefer@gmx.net>
Cc: "Alexandre Belloni" <alexandre.belloni@bootlin.com>,
"Heiko Stuebner" <heiko@sntech.de>,
"Sam Ravnborg" <sam@ravnborg.org>,
linux-pwm@vger.kernel.org,
"Linus Walleij" <linus.walleij@linaro.org>,
"Thierry Reding" <thierry.reding@gmail.com>,
"Fabio Estevam" <festevam@gmail.com>,
"open list:REAL TIME CLOCK (RTC) SUBSYSTEM"
<linux-rtc@vger.kernel.org>, "Arnd Bergmann" <arnd@arndb.de>,
"Mauro Carvalho Chehab" <mchehab+huawei@kernel.org>,
"Lee Jones" <lee.jones@linaro.org>,
"Daniel Palmer" <daniel@0x0f.com>,
"Andreas Kemnade" <andreas@kemnade.info>,
"NXP Linux Team" <linux-imx@nxp.com>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
devicetree <devicetree@vger.kernel.org>,
"Stephan Gerhold" <stephan@gerhold.net>,
allen <allen.chen@ite.com.tw>,
"Sascha Hauer" <s.hauer@pengutronix.de>,
"Lubomir Rintel" <lkundrak@v3.sk>,
"Rob Herring" <robh+dt@kernel.org>,
"linux-arm Mailing List" <linux-arm-kernel@lists.infradead.org>,
"Alessandro Zummo" <a.zummo@towertech.it>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
"Mark Brown" <broonie@kernel.org>,
"Pengutronix Kernel Team" <kernel@pengutronix.de>,
"Heiko Stuebner" <heiko.stuebner@theobroma-systems.com>,
"Josua Mayer" <josua.mayer@jm0.eu>,
"Shawn Guo" <shawnguo@kernel.org>,
"David S. Miller" <davem@davemloft.net>
Subject: Re: [PATCH v3 4/7] pwm: ntxec: Add driver for PWM function in Netronix EC
Date: Sat, 3 Oct 2020 11:17:58 +0300 [thread overview]
Message-ID: <CAHp75VeSB4i_QNOX1UbrooNo0twqgbOhoaxnwk5a+=dEFWMzqA@mail.gmail.com> (raw)
In-Reply-To: <20201002233630.GB500800@latitude>
On Sat, Oct 3, 2020 at 2:36 AM Jonathan Neuschäfer
<j.neuschaefer@gmx.net> wrote:
> On Mon, Sep 28, 2020 at 10:35:46AM +0200, Uwe Kleine-König wrote:
> > On Sun, Sep 27, 2020 at 11:10:44PM +0200, Jonathan Neuschäfer wrote:
...
> > You can even check this with an LED using something like:
> >
> > pwm_apply(mypwm, {.enabled = true, .duty_cycle = $big, .period = $big});
> > pwm_apply(mypwm, {.enabled = false, ... });
> >
> > . If the period is completed the LED is on for $big ns, if not the LED
> > is on for a timespan that is probably hardly noticable with the human
> > eye.
>
> The longest configurable period is about 8ms, so it's not long enough to
> see anything. However, after writing enable=0, it can take about a
> second for the PWM signal to turn off... this hardware is a bit weird.
Sounds like you have 1/128 divisor and off/on is done on lower
frequency. (We saw PWMs with an additional 7-bit counter, reminds me
Crystal Cove PMIC PWM).
--
With Best Regards,
Andy Shevchenko
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-10-03 8:18 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-24 19:24 [PATCH v3 0/7] Netronix embedded controller driver for Kobo and Tolino ebook readers Jonathan Neuschäfer
2020-09-24 19:24 ` Jonathan Neuschäfer
2020-09-24 19:24 ` [PATCH v3 1/7] dt-bindings: Add vendor prefix for Netronix, Inc Jonathan Neuschäfer
2020-09-24 19:24 ` Jonathan Neuschäfer
2020-10-12 7:19 ` Uwe Kleine-König
2020-10-12 7:19 ` Uwe Kleine-König
2020-10-12 11:48 ` Lee Jones
2020-10-12 11:48 ` Lee Jones
2020-09-24 19:24 ` [PATCH v3 2/7] dt-bindings: mfd: Add binding for Netronix embedded controller Jonathan Neuschäfer
2020-09-24 19:24 ` Jonathan Neuschäfer
2020-09-29 18:52 ` Rob Herring
2020-09-29 18:52 ` Rob Herring
2020-09-24 19:24 ` [PATCH v3 3/7] mfd: Add base driver " Jonathan Neuschäfer
2020-09-24 19:24 ` Jonathan Neuschäfer
2020-09-25 9:29 ` Andy Shevchenko
2020-09-25 9:29 ` Andy Shevchenko
2020-09-25 21:32 ` Jonathan Neuschäfer
2020-09-25 21:32 ` Jonathan Neuschäfer
2020-09-29 16:37 ` Andy Shevchenko
2020-09-29 16:37 ` Andy Shevchenko
2020-10-02 22:54 ` Jonathan Neuschäfer
2020-10-02 22:54 ` Jonathan Neuschäfer
2020-09-24 19:24 ` [PATCH v3 4/7] pwm: ntxec: Add driver for PWM function in Netronix EC Jonathan Neuschäfer
2020-09-24 19:24 ` Jonathan Neuschäfer
2020-09-25 6:30 ` Uwe Kleine-König
2020-09-25 6:30 ` Uwe Kleine-König
2020-09-27 21:10 ` Jonathan Neuschäfer
2020-09-27 21:10 ` Jonathan Neuschäfer
2020-09-28 8:35 ` Uwe Kleine-König
2020-09-28 8:35 ` Uwe Kleine-König
2020-10-02 23:36 ` Jonathan Neuschäfer
2020-10-02 23:36 ` Jonathan Neuschäfer
2020-10-03 8:17 ` Andy Shevchenko [this message]
2020-10-03 8:17 ` Andy Shevchenko
2020-09-24 19:24 ` [PATCH v3 5/7] rtc: New driver for RTC in Netronix embedded controller Jonathan Neuschäfer
2020-09-24 19:24 ` Jonathan Neuschäfer
2020-09-24 20:40 ` Andreas Kemnade
2020-09-24 20:40 ` Andreas Kemnade
2020-10-02 23:41 ` Jonathan Neuschäfer
2020-10-02 23:41 ` Jonathan Neuschäfer
2020-09-25 5:44 ` Uwe Kleine-König
2020-09-25 5:44 ` Uwe Kleine-König
2020-10-04 1:43 ` Jonathan Neuschäfer
2020-10-04 1:43 ` Jonathan Neuschäfer
2020-10-04 8:42 ` Alexandre Belloni
2020-10-04 8:42 ` Alexandre Belloni
2020-10-11 19:09 ` Jonathan Neuschäfer
2020-10-11 19:09 ` Jonathan Neuschäfer
2020-10-05 7:35 ` Uwe Kleine-König
2020-10-05 7:35 ` Uwe Kleine-König
2020-09-25 9:36 ` Alexandre Belloni
2020-09-25 9:36 ` Alexandre Belloni
2020-09-25 22:00 ` Jonathan Neuschäfer
2020-09-25 22:00 ` Jonathan Neuschäfer
2020-09-24 19:24 ` [PATCH v3 6/7] MAINTAINERS: Add entry for " Jonathan Neuschäfer
2020-09-24 19:24 ` Jonathan Neuschäfer
2020-09-25 5:08 ` [PATCH v3 7/7] ARM: dts: imx50-kobo-aura: Add " Jonathan Neuschäfer
2020-09-25 5:08 ` Jonathan Neuschäfer
2020-10-07 7:46 ` Krzysztof Kozlowski
2020-10-07 7:46 ` Krzysztof Kozlowski
2020-10-11 19:42 ` Jonathan Neuschäfer
2020-10-11 19:42 ` Jonathan Neuschäfer
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