Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752887AbeAJWbr (ORCPT + 1 other); Wed, 10 Jan 2018 17:31:47 -0500 Received: from bhuna.collabora.co.uk ([46.235.227.227]:36972 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752224AbeAJWa5 (ORCPT ); Wed, 10 Jan 2018 17:30:57 -0500 From: Enric Balletbo i Serra To: Daniel Thompson , Doug Anderson , Pavel Machek , Rob Herring Cc: Jingoo Han , Richard Purdie , Jacek Anaszewski , Brian Norris , Guenter Roeck , Lee Jones , Alexandru Stan , linux-leds@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/4] dt-bindings: pwm-backlight: add a num-interpolation-steps property. Date: Wed, 10 Jan 2018 23:30:44 +0100 Message-Id: <20180110223046.17696-3-enric.balletbo@collabora.com> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20180110223046.17696-1-enric.balletbo@collabora.com> References: <20180110223046.17696-1-enric.balletbo@collabora.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: The num-interpolated-steps property specifies the number of interpolated steps between each value of brightness-level table. This is useful for high resolution PWMs to not have to list out every possible value in the brightness-level array. Signed-off-by: Enric Balletbo i Serra --- .../bindings/leds/backlight/pwm-backlight.txt | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt b/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt index 310810906613..605432c910c5 100644 --- a/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt +++ b/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt @@ -21,6 +21,11 @@ Optional properties: and enabling the backlight using GPIO. - pwm-off-delay-ms: Delay in ms between disabling the backlight using GPIO and setting PWM value to 0. + - num-interpolated-steps: Number of interpolated steps between each value + of brightness-levels table. This way a high + resolution pwm duty cycle can be used without + having to list out every possible value in the + brightness-level array. [0]: Documentation/devicetree/bindings/pwm/pwm.txt [1]: Documentation/devicetree/bindings/gpio/gpio.txt @@ -39,3 +44,19 @@ Example: post-pwm-on-delay-ms = <10>; pwm-off-delay-ms = <10>; }; + +Example using num-interpolation-steps: + + backlight { + compatible = "pwm-backlight"; + pwms = <&pwm 0 5000000>; + + brightness-levels = <0 65535>; + num-interpolated-steps = <4096>; + default-brightness-level = <6>; + + power-supply = <&vdd_bl_reg>; + enable-gpios = <&gpio 58 0>; + post-pwm-on-delay-ms = <10>; + pwm-off-delay-ms = <10>; + }; -- 2.15.1