From: Chen-Yu Tsai <wenst@chromium.org>
Date: Thu, 1 Dec 2022 16:42:26 +0800
Subject: [PATCH] arm64: dts: mediatek: mt8183: Fix systimer 13 MHz clock
 description
References: bsc#1012628
Patch-mainline: 6.2.3
Git-commit: ce8a06b5bac75ccce99c0cf91b96b767d64f28a7

[ Upstream commit ce8a06b5bac75ccce99c0cf91b96b767d64f28a7 ]

The systimer block derives its 13 MHz clock by dividing the main 26 MHz
oscillator clock by 2 internally, not through the TOPCKGEN clock
controller.

On the MT8183 this divider is set either by power-on-reset or by the
bootloader. The bootloader may then make the divider unconfigurable to,
but can be read out by, the operating system.

Making the systimer block take the 26 MHz clock directly requires
changing the implementations. As an ABI compatible fix, change the
input clock of the systimer block a fixed factor divide-by-2 clock
that takes the 26 MHz oscillator as its input.

Fixes: 5bc8e2875ffb ("arm64: dts: mt8183: add systimer0 device node")
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20221201084229.3464449-2-wenst@chromium.org
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 arch/arm64/boot/dts/mediatek/mt8183.dtsi | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/boot/dts/mediatek/mt8183.dtsi b/arch/arm64/boot/dts/mediatek/mt8183.dtsi
index 402136bf..268a1f28 100644
--- a/arch/arm64/boot/dts/mediatek/mt8183.dtsi
+++ b/arch/arm64/boot/dts/mediatek/mt8183.dtsi
@@ -585,6 +585,15 @@ psci {
 		method = "smc";
 	};
 
+	clk13m: fixed-factor-clock-13m {
+		compatible = "fixed-factor-clock";
+		#clock-cells = <0>;
+		clocks = <&clk26m>;
+		clock-div = <2>;
+		clock-mult = <1>;
+		clock-output-names = "clk13m";
+	};
+
 	clk26m: oscillator {
 		compatible = "fixed-clock";
 		#clock-cells = <0>;
@@ -968,8 +977,7 @@ systimer: timer@10017000 {
 				     "mediatek,mt6765-timer";
 			reg = <0 0x10017000 0 0x1000>;
 			interrupts = <GIC_SPI 200 IRQ_TYPE_LEVEL_HIGH>;
-			clocks = <&topckgen CLK_TOP_CLK13M>;
-			clock-names = "clk13m";
+			clocks = <&clk13m>;
 		};
 
 		iommu: iommu@10205000 {
-- 
2.35.3