linux-kernel - Re: [PATCH] ARM: dts: dra7: Correct clock tree for sys_32k

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <56E6A83B.5000908@ti.com>
Date:	Mon, 14 Mar 2016 17:32:03 +0530
From:	Keerthy <a0393675@...com>
To:	Keerthy <j-keerthy@...com>, <tony@...mide.com>,
	<linux-omap@...r.kernel.org>, <devicetree@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>, <robh+dt@...nel.org>
CC:	<galak@...eaurora.org>, <mark.rutland@....com>
Subject: Re: [PATCH] ARM: dts: dra7: Correct clock tree for sys_32k_ck



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@...com>
> ---
> 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>;
> +	};
>   };
>