On Wednesday 22 September 2021 17:16:22 Gregory CLEMENT wrote:

Hello Pali,

quoted

This change defines DT node for UART clock "marvell,armada-3700-uart-clock"
and use this UART clock as a base clock for all UART devices.

Sorry to not have pointed this earlier but I found something a little
unusual, see below:

quoted

Signed-off-by: Pali Rohár <pali@kernel.org>
---
 arch/arm64/boot/dts/marvell/armada-3720-db.dts    |  4 ++++
 .../boot/dts/marvell/armada-3720-espressobin.dtsi |  4 ++++
 .../boot/dts/marvell/armada-3720-turris-mox.dts   |  4 ++++
 arch/arm64/boot/dts/marvell/armada-3720-uDPU.dts  |  4 ++++
 arch/arm64/boot/dts/marvell/armada-37xx.dtsi      | 15 +++++++++++++--
 5 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/boot/dts/marvell/armada-3720-db.dts b/arch/arm64/boot/dts/marvell/armada-3720-db.dts
index 3e5789f37206..accf014a6a1e 100644
--- a/arch/arm64/boot/dts/marvell/armada-3720-db.dts
+++ b/arch/arm64/boot/dts/marvell/armada-3720-db.dts

@@ -191,6 +191,10 @@
 	};
 };
 
+&uartclk {
+	status = "okay";

I found unusual to have to enable the clock at device tree level.
Usually the clock driver is always loaded and then the clock is really
enabled or disabled through the clock framework.

[...]

quoted

diff --git a/arch/arm64/boot/dts/marvell/armada-37xx.dtsi b/arch/arm64/boot/dts/marvell/armada-37xx.dtsi
index 9acc5d2b5a00..5bc61c9615f5 100644
--- a/arch/arm64/boot/dts/marvell/armada-37xx.dtsi
+++ b/arch/arm64/boot/dts/marvell/armada-37xx.dtsi

@@ -132,10 +132,21 @@
 				reg = <0x11500 0x40>;
 			};
 
+			uartclk: uartclk@12000 {
+				compatible = "marvell,armada-3700-uart-clock";
+				reg = <0x12010 0x4>, <0x12210 0x4>;
+				clocks = <&tbg 0>, <&tbg 1>, <&tbg 2>,
+					<&tbg 3>, <&xtalclk>;
+				clock-names = "TBG-A-P", "TBG-B-P", "TBG-A-S",
+					"TBG-B-S", "xtal";
+				#clock-cells = <1>;

I think you could remove the following line and thanks to this there
won't be any change in the dts of the board:

quoted

+				status = "disabled";

After removing "status" from dtsi and then also from board bts files,
UART is still working fine.

So I will include this change into V6.

Is there anything else?

quoted

+			};
+

Gregory

quoted

 			uart0: serial@12000 {
 				compatible = "marvell,armada-3700-uart";
 				reg = <0x12000 0x18>;
-				clocks = <&xtalclk>;
+				clocks = <&uartclk 0>;
 				interrupts =
 				<GIC_SPI 11 IRQ_TYPE_LEVEL_HIGH>,
 				<GIC_SPI 12 IRQ_TYPE_LEVEL_HIGH>,

@@ -147,7 +158,7 @@
 			uart1: serial@12200 {
 				compatible = "marvell,armada-3700-uart-ext";
 				reg = <0x12200 0x30>;
-				clocks = <&xtalclk>;
+				clocks = <&uartclk 1>;
 				interrupts =
 				<GIC_SPI 30 IRQ_TYPE_EDGE_RISING>,
 				<GIC_SPI 31 IRQ_TYPE_EDGE_RISING>;

-- 
2.20.1

-- 
Gregory Clement, Bootlin
Embedded Linux and Kernel engineering
http://bootlin.com

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