Re: [PATCH] ARM: dts: dra7: Correct clock tree for sys_32k_ck

[Keerthy]

On Monday 14 March 2016 05:29 PM, Keerthy wrote:
> This is w.r.t J6/J6eco: 32clk is pseudo (erratum i856) - clock source.
> Errata i856 for the AM572x (DRA7xx) points out that the 32.768KHz external
> crystal is not enabled at power up. Instead the CPU falls back to using
> an emulation for the 32KHz clock which is SYSCLK1/610.  SYSCLK1 is usually
> 20MHz on boards so far (which gives an emulated frequency of 32.786KHz)

Missing signed-off. Please ignore this patch.

> Modelling the same in device tree.
>
> Signed-off-by: Keerthy <j-keerthy@xxxxxx>
> ---
> Errata Document: http://www.ti.com/lit/er/sprz429h/sprz429h.pdf
> Errata number: i856
>
> Tested the debugfs clock tree nodes on DRA7-EVM.
>
>   arch/arm/boot/dts/dra7xx-clocks.dtsi | 18 +++++++++++++++++-
>   1 file changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/boot/dts/dra7xx-clocks.dtsi b/arch/arm/boot/dts/dra7xx-clocks.dtsi
> index 357bede..7f1f892 100644
> --- a/arch/arm/boot/dts/dra7xx-clocks.dtsi
> +++ b/arch/arm/boot/dts/dra7xx-clocks.dtsi
> @@ -98,12 +98,20 @@
>   		clock-frequency = <32768>;
>   	};
>
> -	sys_32k_ck: sys_32k_ck {
> +	sys_clk32_crystal_ck: sys_clk32_crystal_ck {
>   		#clock-cells = <0>;
>   		compatible = "fixed-clock";
>   		clock-frequency = <32768>;
>   	};
>
> +	sys_clk32_pseudo_ck: sys_clk32_pseudo_ck {
> +		#clock-cells = <0>;
> +		compatible = "fixed-factor-clock";
> +		clocks = <&sys_clkin1>;
> +		clock-mult = <1>;
> +		clock-div = <610>;
> +	};
> +
>   	virt_12000000_ck: virt_12000000_ck {
>   		#clock-cells = <0>;
>   		compatible = "fixed-clock";
> @@ -2146,4 +2154,12 @@
>   		ti,bit-shift = <0>;
>   		reg = <0x558>;
>   	};
> +
> +	sys_32k_ck: sys_32k_ck {
> +		#clock-cells = <0>;
> +		compatible = "ti,mux-clock";
> +		clocks = <&sys_clk32_crystal_ck>, <&sys_clk32_pseudo_ck>, <&sys_clk32_pseudo_ck>, <&sys_clk32_pseudo_ck>;
> +		ti,bit-shift = <8>;
> +		reg = <0x6c4>;
> +	};
>   };