Re: [PATCH v2 1/2] arm64: dts: amlogic: t7: use the real UART pclk

[Neil Armstrong <neil.armstrong@linaro.org>]

On 8/23/26 13:53, Lucas Tanure wrote:
> uart_a listed the 24MHz crystal for all three of its clocks because the
> T7 clock controller driver did not exist when these boards were added.
> 
> That leaves the real UART bus clock without a user, so the kernel
> turns it off when it disables unused clocks at the end of boot, and
> the board hangs.
> 
> Update the board DTS files to point uart_a's pclk to CLKID_SYS_UART_A
> instead of the dummy crystal clock.
> 
> Fixes: 4fef056588f5 ("arm64: dts: amlogic-t7-a311d2-khadas-vim4: add initial device-tree")
> Fixes: 6f048cc7a635 ("arm64: dts: add board AN400")
> Signed-off-by: Lucas Tanure <tanure@linux.com>
> Assisted-by: Claude:claude-fable-5
> ---
>   arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-an400.dts       | 2 +-
>   arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts | 2 +-
>   2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-an400.dts b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-an400.dts
> index cab2ee9ea0d3..ca7536f772ff 100644
> --- a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-an400.dts
> +++ b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-an400.dts
> @@ -33,7 +33,7 @@ xtal: xtal-clk {
>   };
>   
>   &uart_a {
> -	clocks = <&xtal>, <&xtal>, <&xtal>;
> +	clocks = <&xtal>, <&clkc_periphs CLKID_SYS_UART_A>, <&xtal>;
>   	clock-names = "xtal", "pclk", "baud";
>   	status = "okay";
>   };
> diff --git a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
> index c41525a34b72..75d81ad6830d 100644
> --- a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
> +++ b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
> @@ -266,6 +266,6 @@ &sd_emmc_c {
>   
>   &uart_a {
>   	status = "okay";
> -	clocks = <&xtal>, <&xtal>, <&xtal>;
> +	clocks = <&xtal>, <&clkc_periphs CLKID_SYS_UART_A>, <&xtal>;
>   	clock-names = "xtal", "pclk", "baud";
>   };

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

Thanks,
Neil

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