Message-ID: <6af5bb93-650e-5ea3-ac14-4e37baf4a902@linaro.org>
Date:   Wed, 8 Mar 2023 13:19:51 +0100
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From:   neil.armstrong@linaro.org
Reply-To: neil.armstrong@linaro.org
Subject: Re: [PATCH v3 3/3] arm64: dts: meson-g12-common: Use the G12A UART
 compatible string
Content-Language: en-US
To:     Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
        linux-amlogic@lists.infradead.org, devicetree@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        jirislaby@kernel.org, krzysztof.kozlowski+dt@linaro.org,
        robh+dt@kernel.org, gregkh@linuxfoundation.org,
        Christian Hewitt <christianshewitt@gmail.com>
References: <20230307222651.2106615-1-martin.blumenstingl@googlemail.com>
 <20230307222651.2106615-4-martin.blumenstingl@googlemail.com>
Organization: Linaro Developer Services
In-Reply-To: <20230307222651.2106615-4-martin.blumenstingl@googlemail.com>
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On 07/03/2023 23:26, Martin Blumenstingl wrote:
> 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
> 
> Changes from v2 -> v3:
> - none
> 
> 
>   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>;

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>