Thread (35 messages) 35 messages, 6 authors, 2022-01-25

Re: [PATCH v7 5/6] arm64: dts: marvell: armada-37xx: add device node for UART clock and use it

From: Gregory CLEMENT <gregory.clement@bootlin.com>
Date: 2021-10-13 14:13:32
Also in: linux-clk, linux-devicetree, linux-serial, lkml

Hello Pali,
quoted hunk ↗ jump to hunk
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.

Signed-off-by: Pali Rohár <pali@kernel.org>

---
Changes in v6:
* Do not disable uartclk by default
* Rename node to clock-controller@12010
---
 arch/arm64/boot/dts/marvell/armada-37xx.dtsi | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/boot/dts/marvell/armada-37xx.dtsi b/arch/arm64/boot/dts/marvell/armada-37xx.dtsi
index 9acc5d2b5a00..f9bfe73d8ec2 100644
--- a/arch/arm64/boot/dts/marvell/armada-37xx.dtsi
+++ b/arch/arm64/boot/dts/marvell/armada-37xx.dtsi
@@ -132,10 +132,20 @@
 				reg = <0x11500 0x40>;
 			};
 
+			uartclk: clock-controller@12010 {
+				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>;
+			};
+
 			uart0: serial@12000 {
 				compatible = "marvell,armada-3700-uart";
 				reg = <0x12000 0x18>;
-				clocks = <&xtalclk>;
+				clocks = <&uartclk 0>;
What happens if we have a new kernel using on old device tree ?

Gregory
quoted hunk ↗ jump to hunk
 				interrupts =
 				<GIC_SPI 11 IRQ_TYPE_LEVEL_HIGH>,
 				<GIC_SPI 12 IRQ_TYPE_LEVEL_HIGH>,
@@ -147,7 +157,7 @@
 			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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