[PATCH/RFC] ARM: shmobile: lager: Add I2C2 clock frequency to device tree

[PATCH/RFC] ARM: shmobile: lager: Add I2C2 clock frequency to device tree

[Simon Horman]

From: Ryo Kataoka <ryo.kataoka.wt@renesas.com>

Signed-off-by: Ryo Kataoka <ryo.kataoka.wt@renesas.com>
[simon: rebased]
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
---
Based on the renesas-devel-20141030-v3.18-rc2 branch of my renesas tree

If this is useful I wonder if it is should be set in the lager board DTS
file instead of the r8a7790 SoC DTSI file.


 arch/arm/boot/dts/r8a7790-lager.dts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/boot/dts/r8a7790-lager.dts b/arch/arm/boot/dts/r8a7790-lager.dts
index 830f2e8..32c7e48 100644
--- a/arch/arm/boot/dts/r8a7790-lager.dts
+++ b/arch/arm/boot/dts/r8a7790-lager.dts
@@ -426,6 +426,7 @@
 
 &iic2	{
 	status = "ok";
+	clock-frequency = <400000>;
 	pinctrl-0 = <&iic2_pins>;
 	pinctrl-names = "default";
 
-- 
2.1.1

Re: [PATCH/RFC] ARM: shmobile: lager: Add I2C2 clock frequency to device tree

[Wolfram Sang]

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On Thu, Oct 30, 2014 at 02:55:20PM +0900, Simon Horman wrote:
> From: Ryo Kataoka <ryo.kataoka.wt@renesas.com>
> 
> Signed-off-by: Ryo Kataoka <ryo.kataoka.wt@renesas.com>
> [simon: rebased]
> Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
> ---
> Based on the renesas-devel-20141030-v3.18-rc2 branch of my renesas tree
> 
> If this is useful I wonder if it is should be set in the lager board DTS
> file instead of the r8a7790 SoC DTSI file.

? This IS set in the .dts and not the .dtsi.

400kHz should never be set in a .dtsi. Not all i2c slave devices support
it. 100kHz is the default which all slaves need to support. But since
I've seen cases where the board needs to lower even further because of
board design issues, I'm getting reluctant to set even 100kHz in dtsi
files in general.

> 
> 
>  arch/arm/boot/dts/r8a7790-lager.dts | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/arm/boot/dts/r8a7790-lager.dts b/arch/arm/boot/dts/r8a7790-lager.dts
> index 830f2e8..32c7e48 100644
> --- a/arch/arm/boot/dts/r8a7790-lager.dts
> +++ b/arch/arm/boot/dts/r8a7790-lager.dts
> @@ -426,6 +426,7 @@
>  
>  &iic2	{
>  	status = "ok";
> +	clock-frequency = <400000>;
>  	pinctrl-0 = <&iic2_pins>;
>  	pinctrl-names = "default";
>  
> -- 
> 2.1.1
> 

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Re: [PATCH/RFC] ARM: shmobile: lager: Add I2C2 clock frequency to device tree

[Simon Horman]

On Thu, Oct 30, 2014 at 02:54:18PM +0100, Wolfram Sang wrote:
> On Thu, Oct 30, 2014 at 02:55:20PM +0900, Simon Horman wrote:
> > From: Ryo Kataoka <ryo.kataoka.wt@renesas.com>
> > 
> > Signed-off-by: Ryo Kataoka <ryo.kataoka.wt@renesas.com>
> > [simon: rebased]
> > Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
> > ---
> > Based on the renesas-devel-20141030-v3.18-rc2 branch of my renesas tree
> > 
> > If this is useful I wonder if it is should be set in the lager board DTS
> > file instead of the r8a7790 SoC DTSI file.
> 
> ? This IS set in the .dts and not the .dtsi.

So it is. I got confused between several similar patches.

> 400kHz should never be set in a .dtsi. Not all i2c slave devices support
> it. 100kHz is the default which all slaves need to support. But since
> I've seen cases where the board needs to lower even further because of
> board design issues, I'm getting reluctant to set even 100kHz in dtsi
> files in general.

Thanks, I will drop this patch.

> 
> > 
> > 
> >  arch/arm/boot/dts/r8a7790-lager.dts | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/arch/arm/boot/dts/r8a7790-lager.dts b/arch/arm/boot/dts/r8a7790-lager.dts
> > index 830f2e8..32c7e48 100644
> > --- a/arch/arm/boot/dts/r8a7790-lager.dts
> > +++ b/arch/arm/boot/dts/r8a7790-lager.dts
> > @@ -426,6 +426,7 @@
> >  
> >  &iic2	{
> >  	status = "ok";
> > +	clock-frequency = <400000>;
> >  	pinctrl-0 = <&iic2_pins>;
> >  	pinctrl-names = "default";
> >  
> > -- 
> > 2.1.1
> >