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From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
To: linux-amlogic@lists.infradead.org, devicetree@vger.kernel.org
Cc: neil.armstrong@linaro.org,
	Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
	gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
	robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org,
	jirislaby@kernel.org, linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 3/3] arm64: dts: meson-g12-common: Use the G12A UART compatible string
Date: Mon,  6 Mar 2023 20:42:23 +0100	[thread overview]
Message-ID: <20230306194223.1869814-4-martin.blumenstingl@googlemail.com> (raw)
In-Reply-To: <20230306194223.1869814-1-martin.blumenstingl@googlemail.com>

Switch meson-12-common.dtsi to use the Meson G12A specific UART
compatible string. This enables the "divide XTAL by 2" divider which
improves support for UART attached Bluetooth modules (for example
RTL8822CS) running at a baud rate of 1500000. Without dividing XTAL
(24MHz) by 2 a baud rate of 1500000 cannot be generated cleanly and the
resulting jitter breaks communication with the module.

Tested-by: Christian Hewitt <christianshewitt@gmail.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
Greg, please don't take this through your tree. I included this patch
to show the overall goal of this series. If Neil won't take this as
part of another series then I'll send it separately.

Changes from v1 -> v2:
- keep meson-gx-uart as fallback compatible string


 arch/arm64/boot/dts/amlogic/meson-g12-common.dtsi | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/boot/dts/amlogic/meson-g12-common.dtsi b/arch/arm64/boot/dts/amlogic/meson-g12-common.dtsi
index 123a56f7f818..904bcd4d2acf 100644
--- a/arch/arm64/boot/dts/amlogic/meson-g12-common.dtsi
+++ b/arch/arm64/boot/dts/amlogic/meson-g12-common.dtsi
@@ -2046,7 +2046,8 @@ pwm_AO_cd: pwm@2000 {
 			};
 
 			uart_AO: serial@3000 {
-				compatible = "amlogic,meson-gx-uart",
+				compatible = "amlogic,meson-g12a-uart",
+					     "amlogic,meson-gx-uart",
 					     "amlogic,meson-ao-uart";
 				reg = <0x0 0x3000 0x0 0x18>;
 				interrupts = <GIC_SPI 193 IRQ_TYPE_EDGE_RISING>;
@@ -2056,7 +2057,8 @@ uart_AO: serial@3000 {
 			};
 
 			uart_AO_B: serial@4000 {
-				compatible = "amlogic,meson-gx-uart",
+				compatible = "amlogic,meson-g12a-uart",
+					     "amlogic,meson-gx-uart",
 					     "amlogic,meson-ao-uart";
 				reg = <0x0 0x4000 0x0 0x18>;
 				interrupts = <GIC_SPI 197 IRQ_TYPE_EDGE_RISING>;
@@ -2293,7 +2295,8 @@ clk_msr: clock-measure@18000 {
 			};
 
 			uart_C: serial@22000 {
-				compatible = "amlogic,meson-gx-uart";
+				compatible = "amlogic,meson-g12a-uart",
+					     "amlogic,meson-gx-uart";
 				reg = <0x0 0x22000 0x0 0x18>;
 				interrupts = <GIC_SPI 93 IRQ_TYPE_EDGE_RISING>;
 				clocks = <&xtal>, <&clkc CLKID_UART2>, <&xtal>;
@@ -2302,7 +2305,8 @@ uart_C: serial@22000 {
 			};
 
 			uart_B: serial@23000 {
-				compatible = "amlogic,meson-gx-uart";
+				compatible = "amlogic,meson-g12a-uart",
+					     "amlogic,meson-gx-uart";
 				reg = <0x0 0x23000 0x0 0x18>;
 				interrupts = <GIC_SPI 75 IRQ_TYPE_EDGE_RISING>;
 				clocks = <&xtal>, <&clkc CLKID_UART1>, <&xtal>;
@@ -2311,7 +2315,8 @@ uart_B: serial@23000 {
 			};
 
 			uart_A: serial@24000 {
-				compatible = "amlogic,meson-gx-uart";
+				compatible = "amlogic,meson-g12a-uart",
+					     "amlogic,meson-gx-uart";
 				reg = <0x0 0x24000 0x0 0x18>;
 				interrupts = <GIC_SPI 26 IRQ_TYPE_EDGE_RISING>;
 				clocks = <&xtal>, <&clkc CLKID_UART0>, <&xtal>;
-- 
2.39.2


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      parent reply	other threads:[~2023-03-06 19:43 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-06 19:42 [PATCH v2 0/3] meson-uart: Use "divide XTAL by 2" bit on G12A Martin Blumenstingl
2023-03-06 19:42 ` [PATCH v2 1/3] dt-bindings: serial: amlogic,meson-uart: Add compatible string for G12A Martin Blumenstingl
2023-03-07  8:47   ` Krzysztof Kozlowski
2023-03-06 19:42 ` [PATCH v2 2/3] tty: serial: meson: Add a new compatible string for the G12A SoC Martin Blumenstingl
2023-03-06 19:42 ` Martin Blumenstingl [this message]

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