[PATCH 1/4] ARM: imx: update i.MX6Q dts setting of VDDARM_CAP voltage

[Shawn Guo]

On Mon, Dec 16, 2013 at 04:07:37PM -0500, Anson Huang wrote:
> According to datasheet, VDD_CACHE_CAP must not exceed VDDARM_CAP
> by more than 200mV, as all of i.MX6Q boards' VDD_CACHE_CAP currently
> are connected to VDDSOC_CAP, so we need to follow this rule by
> increasing VDDARM_CAP's voltage.

The commit log is a little bit vague, and you should probably make the
following points clearer.

1. This is only a problem for 396MHz operating-point, and the other 3
   are fine.

2. What's the VDDSOC_CAP value for 396MHz operating-point right now?
   From what I read drivers/cpufreq/imx6q-cpufreq.c, it's 1250mV.  Then
   the obvious question is why we're not increasing VDDARM_CAP to
   1250 - 200 = 1050mV but 975mV?

Shawn

> 
> Signed-off-by: Anson Huang <b20788 at freescale.com>
> ---
>  arch/arm/boot/dts/imx6q.dtsi |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm/boot/dts/imx6q.dtsi b/arch/arm/boot/dts/imx6q.dtsi
> index 101c434..e7e8332 100644
> --- a/arch/arm/boot/dts/imx6q.dtsi
> +++ b/arch/arm/boot/dts/imx6q.dtsi
> @@ -28,7 +28,7 @@
>  				1200000 1275000
>  				996000  1250000
>  				792000  1150000
> -				396000  950000
> +				396000  975000
>  			>;
>  			clock-latency = <61036>; /* two CLK32 periods */
>  			clocks = <&clks 104>, <&clks 6>, <&clks 16>,
> -- 
> 1.7.9.5
> 
>