linux-kernel - [PATCH 3/3] ARM: dts: rockchip: Remove 0 point in backlight

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Date:   Mon, 20 Jul 2020 21:25:22 -0700
From:   Alexandru Stan <amstan@...omium.org>
To:     Thierry Reding <thierry.reding@...il.com>,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>, Lee Jones <lee.jones@...aro.org>,
        Daniel Thompson <daniel.thompson@...aro.org>,
        Jingoo Han <jingoohan1@...il.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Heiko Stuebner <heiko@...ech.de>,
        Rob Herring <robh+dt@...nel.org>
Cc:     Matthias Kaehlcke <mka@...omium.org>,
        Douglas Anderson <dianders@...omium.org>,
        Enric Balletbo i Serra <enric.balletbo@...labora.com>,
        Alexandru Stan <amstan@...omium.org>,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, linux-rockchip@...ts.infradead.org
Subject: [PATCH 3/3] ARM: dts: rockchip: Remove 0 point in backlight

After the "PWM backlight interpolation adjustments" patches, the
backlight interpolation works a little differently. The way these
dts files were working before was relying on a bug (IMHO).

Remove the 0-3 range since otherwise we would have a 252 long
interpolation that would slowly go between 0 and 3, looking really bad
in userspace.

We'll still have the 0% point available to userspace, "backlight:
pwm_bl: Artificially add 0% during interpolation" takes care of that.

Signed-off-by: Alexandru Stan <amstan@...omium.org>
---

 arch/arm/boot/dts/rk3288-veyron-jaq.dts    | 2 +-
 arch/arm/boot/dts/rk3288-veyron-minnie.dts | 2 +-
 arch/arm/boot/dts/rk3288-veyron-tiger.dts  | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm/boot/dts/rk3288-veyron-jaq.dts b/arch/arm/boot/dts/rk3288-veyron-jaq.dts
index 171ba6185b6d..af4b21636c08 100644
--- a/arch/arm/boot/dts/rk3288-veyron-jaq.dts
+++ b/arch/arm/boot/dts/rk3288-veyron-jaq.dts
@@ -20,7 +20,7 @@ / {
 
 &backlight {
 	/* Jaq panel PWM must be >= 3%, so start non-zero brightness at 8 */
-	brightness-levels = <0 8 255>;
+	brightness-levels = <8 255>;
 	num-interpolated-steps = <247>;
 };
 
diff --git a/arch/arm/boot/dts/rk3288-veyron-minnie.dts b/arch/arm/boot/dts/rk3288-veyron-minnie.dts
index 383fad1a88a1..b25aa2f3cbee 100644
--- a/arch/arm/boot/dts/rk3288-veyron-minnie.dts
+++ b/arch/arm/boot/dts/rk3288-veyron-minnie.dts
@@ -39,7 +39,7 @@ volum_up {
 
 &backlight {
 	/* Minnie panel PWM must be >= 1%, so start non-zero brightness at 3 */
-	brightness-levels = <0 3 255>;
+	brightness-levels = <3 255>;
 	num-interpolated-steps = <252>;
 };
 
diff --git a/arch/arm/boot/dts/rk3288-veyron-tiger.dts b/arch/arm/boot/dts/rk3288-veyron-tiger.dts
index 069f0c2c1fdf..52a84cbe7a90 100644
--- a/arch/arm/boot/dts/rk3288-veyron-tiger.dts
+++ b/arch/arm/boot/dts/rk3288-veyron-tiger.dts
@@ -23,7 +23,7 @@ / {
 
 &backlight {
 	/* Tiger panel PWM must be >= 1%, so start non-zero brightness at 3 */
-	brightness-levels = <0 3 255>;
+	brightness-levels = <3 255>;
 	num-interpolated-steps = <252>;
 };
 
-- 
2.27.0