diff mbox

ARM: dts: Switch i2c0 to 400kHz on rk3288-evb-rk808

Message ID 1410409815-22200-1-git-send-email-dianders@chromium.org
State New, archived
Headers show

Commit Message

Douglas Anderson Sept. 11, 2014, 4:30 a.m. UTC
We should be able to talk to the PMIC at 400kHz.  No need to talk at
the slow 100kHz.

As measured by ftrace (with a bunch of extra patches, since cpufreq
for rk808 hasn't landed yet):
  before this change: cpu0_set_target() => ~500us
  after this change:  cpu0_set_target() => ~300us

Signed-off-by: Doug Anderson <dianders@chromium.org>
---
 arch/arm/boot/dts/rk3288-evb-rk808.dts | 1 +
 1 file changed, 1 insertion(+)

Comments

addy ke Sept. 11, 2014, 9:17 a.m. UTC | #1
On 11 Sep 2014 12:30, Doug Anderson writes:
> We should be able to talk to the PMIC at 400kHz.  No need to talk at
> the slow 100kHz.
>
> As measured by ftrace (with a bunch of extra patches, since cpufreq
> for rk808 hasn't landed yet):
>   before this change: cpu0_set_target() => ~500us
>   after this change:  cpu0_set_target() => ~300us
>
> Signed-off-by: Doug Anderson <dianders@chromium.org>
> ---
>  arch/arm/boot/dts/rk3288-evb-rk808.dts | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/arch/arm/boot/dts/rk3288-evb-rk808.dts b/arch/arm/boot/dts/rk3288-evb-rk808.dts
> index 36db177..ff522f8 100644
> --- a/arch/arm/boot/dts/rk3288-evb-rk808.dts
> +++ b/arch/arm/boot/dts/rk3288-evb-rk808.dts
> @@ -18,6 +18,7 @@
>  };
>  
>  &i2c0 {
> +	clock-frequency = <400000>;
>  	status = "okay";
>  
>  	rk808: pmic@1b {
I have tested on rk3288-pinky board, it work well. so

Reviewed-by Addy Ke <addy.ke@rock-chips.com>
Tested-by Addy Ke <addy.ke@rock-chips.com>
Heiko Stübner Sept. 11, 2014, 9:23 a.m. UTC | #2
Am Mittwoch, 10. September 2014, 21:30:15 schrieb Doug Anderson:
> We should be able to talk to the PMIC at 400kHz.  No need to talk at
> the slow 100kHz.
> 
> As measured by ftrace (with a bunch of extra patches, since cpufreq
> for rk808 hasn't landed yet):
>   before this change: cpu0_set_target() => ~500us
>   after this change:  cpu0_set_target() => ~300us
> 
> Signed-off-by: Doug Anderson <dianders@chromium.org>

looks harmless :-)

I've added it to my v3.18-next/dts branch with Addy's tags


> ---
>  arch/arm/boot/dts/rk3288-evb-rk808.dts | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/arm/boot/dts/rk3288-evb-rk808.dts
> b/arch/arm/boot/dts/rk3288-evb-rk808.dts index 36db177..ff522f8 100644
> --- a/arch/arm/boot/dts/rk3288-evb-rk808.dts
> +++ b/arch/arm/boot/dts/rk3288-evb-rk808.dts
> @@ -18,6 +18,7 @@
>  };
> 
>  &i2c0 {
> +	clock-frequency = <400000>;
>  	status = "okay";
> 
>  	rk808: pmic@1b {
diff mbox

Patch

diff --git a/arch/arm/boot/dts/rk3288-evb-rk808.dts b/arch/arm/boot/dts/rk3288-evb-rk808.dts
index 36db177..ff522f8 100644
--- a/arch/arm/boot/dts/rk3288-evb-rk808.dts
+++ b/arch/arm/boot/dts/rk3288-evb-rk808.dts
@@ -18,6 +18,7 @@ 
 };
 
 &i2c0 {
+	clock-frequency = <400000>;
 	status = "okay";
 
 	rk808: pmic@1b {