linux-kernel - [PATCH v3 2/4] arm64: dts: exynos: gs101-oriole: configure simple-framebuffer

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Message-Id: <20250115-gs101-simplefb-v3-2-52eca3a582b7@linaro.org>
Date: Wed, 15 Jan 2025 16:11:10 +0000
From: André Draszik <andre.draszik@...aro.org>
To: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, 
 Peter Griffin <peter.griffin@...aro.org>, 
 Tudor Ambarus <tudor.ambarus@...aro.org>, 
 Alim Akhtar <alim.akhtar@...sung.com>
Cc: Will McVicker <willmcvicker@...gle.com>, kernel-team@...roid.com, 
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-arm-kernel@...ts.infradead.org, linux-samsung-soc@...r.kernel.org, 
 André Draszik <andre.draszik@...aro.org>
Subject: [PATCH v3 2/4] arm64: dts: exynos: gs101-oriole: configure
 simple-framebuffer

The bootloader configures the display hardware for a framebuffer at the
given address, let's add a simple-framebuffer node here until we get a
proper DRM driver.

This has several benefits since it's an OLED display:
* energy consumption goes down significantly, as it changes from white
  (as left by bootloader) to black (linux console), and we generally
  don't run out of battery anymore when plugged into a USB port
* less of a burn-in effect I assume
* phone stays cooler due to reduced energy consumption by display

Signed-off-by: André Draszik <andre.draszik@...aro.org>
---
v3:
- replace property 'reg' with 'memory-region' and related properties to
  reduce churn in preparation for Pixel 6Pro support
- drop tags due to that
---
 arch/arm64/boot/dts/exynos/google/gs101-oriole.dts | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/arch/arm64/boot/dts/exynos/google/gs101-oriole.dts b/arch/arm64/boot/dts/exynos/google/gs101-oriole.dts
index e58881c61d53..d3dd411c9bd0 100644
--- a/arch/arm64/boot/dts/exynos/google/gs101-oriole.dts
+++ b/arch/arm64/boot/dts/exynos/google/gs101-oriole.dts
@@ -26,6 +26,16 @@ chosen {
 		/* Bootloader expects bootargs specified otherwise it crashes */
 		bootargs = "";
 		stdout-path = &serial_0;
+
+		/* Use display framebuffer as setup by bootloader */
+		framebuffer0: framebuffer-0 {
+			compatible = "simple-framebuffer";
+			memory-region = <&cont_splash_mem>;
+			width = <1080>;
+			height = <2400>;
+			stride = <(1080 * 4)>;
+			format = "a8r8g8b8";
+		};
 	};
 
 	gpio-keys {
@@ -69,6 +79,13 @@ ufs_0_fixed_vcc_reg: regulator-1 {
 		regulator-boot-on;
 		enable-active-high;
 	};
+
+	reserved-memory {
+		cont_splash_mem: splash@...00000 {
+			reg = <0x0 0xfac00000 (1080 * 2400 * 4)>;
+			no-map;
+		};
+	};
 };
 
 &ext_24_5m {

-- 
2.48.0.rc2.279.g1de40edade-goog