[PATCH 1/3] ARM: dts: renesas: r8a73a4: Fix external clocks and clock rate

Geert Uytterhoeven geert+renesas at glider.be
Mon Jan 15 03:03:03 PST 2024


External clocks should be defined as zero-Hz clocks in the SoC .dtsi,
and overridden in the board .dts when present.

Correct the clock rate of extal1 from 25 to 26 MHz, to match the crystal
oscillator present on the APE6-EVM board.

Fixes: a76809a329d6ebae ("ARM: shmobile: r8a73a4: Common clock framework DT description")
Signed-off-by: Geert Uytterhoeven <geert+renesas at glider.be>
---
Before, DMIPS/MHZ for the Cortex-A15 CPU cores was slightly higher
than on R-Car M2-W, due to most clocks running 4% faster than assumed.

Also verified by measuring I2C clock rates using a logic analyzer.
---
 arch/arm/boot/dts/renesas/r8a73a4-ape6evm.dts | 12 ++++++++++++
 arch/arm/boot/dts/renesas/r8a73a4.dtsi        |  9 ++++++---
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/arch/arm/boot/dts/renesas/r8a73a4-ape6evm.dts b/arch/arm/boot/dts/renesas/r8a73a4-ape6evm.dts
index de87f2682e323866..ae656ee27124c745 100644
--- a/arch/arm/boot/dts/renesas/r8a73a4-ape6evm.dts
+++ b/arch/arm/boot/dts/renesas/r8a73a4-ape6evm.dts
@@ -223,6 +223,18 @@ &cmt1 {
 	status = "okay";
 };
 
+&extal1_clk {
+	clock-frequency = <26000000>;
+};
+
+&extal2_clk {
+	clock-frequency = <48000000>;
+};
+
+&extalr_clk {
+	clock-frequency = <32768>;
+};
+
 &pfc {
 	scifa0_pins: scifa0 {
 		groups = "scifa0_data";
diff --git a/arch/arm/boot/dts/renesas/r8a73a4.dtsi b/arch/arm/boot/dts/renesas/r8a73a4.dtsi
index 704b0e4acb4dedf6..b9c20e8ac14f2156 100644
--- a/arch/arm/boot/dts/renesas/r8a73a4.dtsi
+++ b/arch/arm/boot/dts/renesas/r8a73a4.dtsi
@@ -553,17 +553,20 @@ clocks {
 		extalr_clk: extalr {
 			compatible = "fixed-clock";
 			#clock-cells = <0>;
-			clock-frequency = <32768>;
+			/* This value must be overridden by the board. */
+			clock-frequency = <0>;
 		};
 		extal1_clk: extal1 {
 			compatible = "fixed-clock";
 			#clock-cells = <0>;
-			clock-frequency = <25000000>;
+			/* This value must be overridden by the board. */
+			clock-frequency = <0>;
 		};
 		extal2_clk: extal2 {
 			compatible = "fixed-clock";
 			#clock-cells = <0>;
-			clock-frequency = <48000000>;
+			/* This value must be overridden by the board. */
+			clock-frequency = <0>;
 		};
 		fsiack_clk: fsiack {
 			compatible = "fixed-clock";
-- 
2.34.1




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