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From: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
To: Nishanth Menon <nm@ti.com>, Vignesh Raghavendra <vigneshr@ti.com>,
	Tero Kristo <kristo@kernel.org>
Cc: Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Subject: [PATCH v2] arm64: dts: ti: k3-am64-mcu: remove incorrect UART base clock rates
Date: Tue, 19 Apr 2022 09:51:57 +0200	[thread overview]
Message-ID: <20220419075157.189347-1-matthias.schiffer@ew.tq-group.com> (raw)

We found that (at least some versions of) the sci-fw set the base clock
rate for UARTs in the MCU domain to 96 MHz instead of the expected 48 MHz,
leading to incorrect baud rates when used from Linux.

As the 8250_omap driver will query the actual clock rate from the clk
driver when clock-frequency is unset, removing the incorrect property is
sufficient to fix the baud rate.

Fixes: 8abae9389bdb ("arm64: dts: ti: Add support for AM642 SoC")
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
---

v2: remove incorrect clock-frequency instead of using
    assigned-clock-rates to modify the base clock

 arch/arm64/boot/dts/ti/k3-am64-mcu.dtsi | 2 --
 1 file changed, 2 deletions(-)

diff --git a/arch/arm64/boot/dts/ti/k3-am64-mcu.dtsi b/arch/arm64/boot/dts/ti/k3-am64-mcu.dtsi
index 2bb5c9ff172c..02d4285acbb8 100644
--- a/arch/arm64/boot/dts/ti/k3-am64-mcu.dtsi
+++ b/arch/arm64/boot/dts/ti/k3-am64-mcu.dtsi
@@ -10,7 +10,6 @@ mcu_uart0: serial@4a00000 {
 		compatible = "ti,am64-uart", "ti,am654-uart";
 		reg = <0x00 0x04a00000 0x00 0x100>;
 		interrupts = <GIC_SPI 185 IRQ_TYPE_LEVEL_HIGH>;
-		clock-frequency = <48000000>;
 		current-speed = <115200>;
 		power-domains = <&k3_pds 149 TI_SCI_PD_EXCLUSIVE>;
 		clocks = <&k3_clks 149 0>;
@@ -21,7 +20,6 @@ mcu_uart1: serial@4a10000 {
 		compatible = "ti,am64-uart", "ti,am654-uart";
 		reg = <0x00 0x04a10000 0x00 0x100>;
 		interrupts = <GIC_SPI 186 IRQ_TYPE_LEVEL_HIGH>;
-		clock-frequency = <48000000>;
 		current-speed = <115200>;
 		power-domains = <&k3_pds 160 TI_SCI_PD_EXCLUSIVE>;
 		clocks = <&k3_clks 160 0>;
-- 
2.25.1


WARNING: multiple messages have this Message-ID (diff)
From: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
To: Nishanth Menon <nm@ti.com>, Vignesh Raghavendra <vigneshr@ti.com>,
	Tero Kristo <kristo@kernel.org>
Cc: Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Subject: [PATCH v2] arm64: dts: ti: k3-am64-mcu: remove incorrect UART base clock rates
Date: Tue, 19 Apr 2022 09:51:57 +0200	[thread overview]
Message-ID: <20220419075157.189347-1-matthias.schiffer@ew.tq-group.com> (raw)

We found that (at least some versions of) the sci-fw set the base clock
rate for UARTs in the MCU domain to 96 MHz instead of the expected 48 MHz,
leading to incorrect baud rates when used from Linux.

As the 8250_omap driver will query the actual clock rate from the clk
driver when clock-frequency is unset, removing the incorrect property is
sufficient to fix the baud rate.

Fixes: 8abae9389bdb ("arm64: dts: ti: Add support for AM642 SoC")
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
---

v2: remove incorrect clock-frequency instead of using
    assigned-clock-rates to modify the base clock

 arch/arm64/boot/dts/ti/k3-am64-mcu.dtsi | 2 --
 1 file changed, 2 deletions(-)

diff --git a/arch/arm64/boot/dts/ti/k3-am64-mcu.dtsi b/arch/arm64/boot/dts/ti/k3-am64-mcu.dtsi
index 2bb5c9ff172c..02d4285acbb8 100644
--- a/arch/arm64/boot/dts/ti/k3-am64-mcu.dtsi
+++ b/arch/arm64/boot/dts/ti/k3-am64-mcu.dtsi
@@ -10,7 +10,6 @@ mcu_uart0: serial@4a00000 {
 		compatible = "ti,am64-uart", "ti,am654-uart";
 		reg = <0x00 0x04a00000 0x00 0x100>;
 		interrupts = <GIC_SPI 185 IRQ_TYPE_LEVEL_HIGH>;
-		clock-frequency = <48000000>;
 		current-speed = <115200>;
 		power-domains = <&k3_pds 149 TI_SCI_PD_EXCLUSIVE>;
 		clocks = <&k3_clks 149 0>;
@@ -21,7 +20,6 @@ mcu_uart1: serial@4a10000 {
 		compatible = "ti,am64-uart", "ti,am654-uart";
 		reg = <0x00 0x04a10000 0x00 0x100>;
 		interrupts = <GIC_SPI 186 IRQ_TYPE_LEVEL_HIGH>;
-		clock-frequency = <48000000>;
 		current-speed = <115200>;
 		power-domains = <&k3_pds 160 TI_SCI_PD_EXCLUSIVE>;
 		clocks = <&k3_clks 160 0>;
-- 
2.25.1


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             reply	other threads:[~2022-04-19  7:52 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-19  7:51 Matthias Schiffer [this message]
2022-04-19  7:51 ` [PATCH v2] arm64: dts: ti: k3-am64-mcu: remove incorrect UART base clock rates Matthias Schiffer
2022-04-22  8:48 ` Vignesh Raghavendra
2022-04-22  8:48   ` Vignesh Raghavendra
2022-04-27 15:17 ` Vignesh Raghavendra
2022-04-27 15:17   ` Vignesh Raghavendra

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