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

Reviewed-by: Peter Griffin <peter.griffin@linaro.org>
Tested-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: André Draszik <andre.draszik@linaro.org>
---
This is marked as v2, because it has been split out from my original
series in [1] to make it independent, for two reasons:
* drop the dependency on other patches touching the same file
* no need to mingle this one with adding Pixel 6 Pro support

Other than that, there are no changes and I kept the existing trailers.

For those who want to try this out:
The stock bootloader disables the decon hardware trigger before jumping
to Linux, preventing framebuffer updates from reaching the display. We
have added a work-around in our Yocto BSP layer for the time being
(until a proper display exists upstream). An alternative might be to
port and use uniLoader from https://github.com/ivoszbg/uniLoader, as
seems to be done for some other Exynos platforms.
---
Changes in v2:
- split out of original series
- Link to v1 series: https://lore.kernel.org/r/20241216-gs101-simplefb-v1-0-8ccad1830281@linaro.org
---
 arch/arm64/boot/dts/exynos/google/gs101-oriole.dts | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/arch/arm64/boot/dts/exynos/google/gs101-oriole.dts b/arch/arm64/boot/dts/exynos/google/gs101-oriole.dts
index 387fb779bd29..a00cb27e167e 100644
--- a/arch/arm64/boot/dts/exynos/google/gs101-oriole.dts
+++ b/arch/arm64/boot/dts/exynos/google/gs101-oriole.dts
@@ -22,9 +22,23 @@ aliases {
 	};
 
 	chosen {
+		#address-cells = <2>;
+		#size-cells = <1>;
+		ranges;
+
 		/* Bootloader expects bootargs specified otherwise it crashes */
 		bootargs = "";
 		stdout-path = &serial_0;
+
+		/* Use display framebuffer as setup by bootloader */
+		framebuffer0: framebuffer@fac00000 {
+			compatible = "simple-framebuffer";
+			reg = <0x0 0xfac00000 (1080 * 2400 * 4)>;
+			width = <1080>;
+			height = <2400>;
+			stride = <(1080 * 4)>;
+			format = "a8r8g8b8";
+		};
 	};
 
 	gpio-keys {
@@ -68,6 +82,13 @@ ufs_0_fixed_vcc_reg: regulator-1 {
 		regulator-boot-on;
 		enable-active-high;
 	};
+
+	reserved-memory {
+		cont_splash_mem: splash@fac00000 {
+			reg = <0x0 0xfac00000 (1080 * 2400 * 4)>;
+			no-map;
+		};
+	};
 };
 
 &ext_24_5m {

---
base-commit: 8503810115fbff903f626adc0788daa048302bc0
change-id: 20241219-gs101-simplefb-oriole-d3fad1f5b498

Best regards,
-- 
André Draszik <andre.draszik@linaro.org>

On Fri, 20 Dec 2024 10:32:50 +0000, André Draszik wrote:
> 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
> 
> [...]

Applied, thanks!

[1/1] arm64: dts: exynos: gs101-oriole: configure simple-framebuffer
      https://git.kernel.org/krzk/linux/c/e32a7fc0b14564f9094f90053c74f500809ddf3c

Best regards,
-- 
Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>