From mboxrd@z Thu Jan 1 00:00:00 1970 From: Claudiu Beznea Subject: [PATCH v3 06/10] pwm: add PWM modes Date: Thu, 22 Feb 2018 14:01:17 +0200 Message-ID: <1519300881-8136-7-git-send-email-claudiu.beznea@microchip.com> References: <1519300881-8136-1-git-send-email-claudiu.beznea@microchip.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1519300881-8136-1-git-send-email-claudiu.beznea@microchip.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: thierry.reding@gmail.com, shc_work@mail.ru, kgene@kernel.org, krzk@kernel.org, linux@armlinux.org.uk, mturquette@baylibre.com, sboyd@codeaurora.org, jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com, rodrigo.vivi@intel.com, airlied@linux.ie, kamil@wypas.org, b.zolnierkie@samsung.com, jdelvare@suse.com, linux@roeck-us.net, dmitry.torokhov@gmail.com, rpurdie@rpsys.net, jacek.anaszewski@gmail.com, pavel@ucw.cz, mchehab@kernel.org, sean@mess.org, lee.jones@linaro.org, daniel.thompson@linaro.org, jingoohan1@gmail.com, milo.kim@ti.com, robh+dt@kernel.org, mark.rutland@arm.com, corbet@lwn.net, nicolas.ferre@microchip.com, alexandre.belloni@free-electrons.com Cc: linux-hwmon@vger.kernel.org, linux-pwm@vger.kernel.org, linux-fbdev@vger.kernel.org, linux-samsung-soc@vger.kernel.org, devicetree@vger.kernel.org, intel-gfx@lists.freedesktop.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Claudiu Beznea , linux-leds@vger.kernel.org, linux-input@vger.kernel.org, linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org List-Id: linux-input@vger.kernel.org Add PWM normal and complementary modes. Signed-off-by: Claudiu Beznea --- Documentation/devicetree/bindings/pwm/pwm.txt | 9 +++++++-- Documentation/pwm.txt | 26 +++++++++++++++++++++++--- include/dt-bindings/pwm/pwm.h | 1 + 3 files changed, 31 insertions(+), 5 deletions(-) diff --git a/Documentation/devicetree/bindings/pwm/pwm.txt b/Documentation/devicetree/bindings/pwm/pwm.txt index 8556263b8502..c2b4b9ba0e3f 100644 --- a/Documentation/devicetree/bindings/pwm/pwm.txt +++ b/Documentation/devicetree/bindings/pwm/pwm.txt @@ -46,11 +46,16 @@ period in nanoseconds. Optionally, the pwm-specifier can encode a number of flags (defined in ) in a third cell: - PWM_POLARITY_INVERTED: invert the PWM signal polarity +- PWM_DTMODE_COMPLEMENTARY: PWM complementary working mode (for PWM +channels two outputs); if not specified, the default for PWM channel will +be used -Example with optional PWM specifier for inverse polarity +Example with optional PWM specifier for inverse polarity and complementary +mode: bl: backlight { - pwms = <&pwm 0 5000000 PWM_POLARITY_INVERTED>; + pwms = <&pwm 0 5000000 + (PWM_DTMODE_COMPLEMENTARY | PWM_POLARITY_INVERTED)>; pwm-names = "backlight"; }; diff --git a/Documentation/pwm.txt b/Documentation/pwm.txt index 8fbf0aa3ba2d..59592f8cc381 100644 --- a/Documentation/pwm.txt +++ b/Documentation/pwm.txt @@ -61,9 +61,9 @@ In addition to the PWM state, the PWM API also exposes PWM arguments, which are the reference PWM config one should use on this PWM. PWM arguments are usually platform-specific and allows the PWM user to only care about dutycycle relatively to the full period (like, duty = 50% of the -period). struct pwm_args contains 2 fields (period and polarity) and should -be used to set the initial PWM config (usually done in the probe function -of the PWM user). PWM arguments are retrieved with pwm_get_args(). +period). struct pwm_args contains 3 fields (period, polarity and mode) and +should be used to set the initial PWM config (usually done in the probe +function of the PWM user). PWM arguments are retrieved with pwm_get_args(). Using PWMs with the sysfs interface ----------------------------------- @@ -110,6 +110,26 @@ channel that was exported. The following properties will then be available: - 0 - disabled - 1 - enabled + mode + Get/set PWM channel working mode. + + Normal mode - for PWM channels with one output; this should be the + default working mode for every PWM channel; output waveforms looks + like this: + __ __ __ __ + PWM __| |__| |__| |__| |__ + <--T--> + + Complementary mode - for PWM channels two outputs; output waveforms + looks line this: + __ __ __ __ + PWMH1 __| |__| |__| |__| |__ + __ __ __ __ __ + PWML1 |__| |__| |__| |__| + <--T--> + + Where T is the signal period. + Implementing a PWM driver ------------------------- diff --git a/include/dt-bindings/pwm/pwm.h b/include/dt-bindings/pwm/pwm.h index ab9a077e3c7d..b4d61269aced 100644 --- a/include/dt-bindings/pwm/pwm.h +++ b/include/dt-bindings/pwm/pwm.h @@ -11,5 +11,6 @@ #define _DT_BINDINGS_PWM_PWM_H #define PWM_POLARITY_INVERTED (1 << 0) +#define PWM_DTMODE_COMPLEMENTARY (1 << 1) #endif -- 2.7.4