Re: [PATCH 7/7] ARM: tegra: Add the EC i2c tunnel to tegra124-venice2

From: Doug Anderson
Date: Mon Apr 21 2014 - 15:36:00 EST


Stephen,

On Mon, Apr 21, 2014 at 11:18 AM, Stephen Warren <swarren@xxxxxxxxxxxxx> wrote:
> On 04/17/2014 11:59 AM, Doug Anderson wrote:
>> This adds the EC i2c tunnel (and devices under it) to the
>> tegra124-venice2 device tree.
>
> The series,
> Tested-by: Stephen Warren <swarren@xxxxxxxxxx>
>
> I can apply this one patch once the other patches in the series are
> acked or applied (in order to make sure the DT binding is acceptable to
> others).

Sounds good. If I don't get any feedback (positive or negative) in
the next few days I'll resend with your Tested-by.


> I guess I'll send separate patches for tegra_defconfig and
> multi_v7_defconfig to add the required options once I've applied this,
> unless you beat me to it.
>
>> diff --git a/arch/arm/boot/dts/tegra124-venice2.dts b/arch/arm/boot/dts/tegra124-venice2.dts
>
>> aliases {
>> + i2c20 = "/spi@0,7000d400/cros-ec@0/i2c-tunnel";
>
> Is that needed? I'd prefer not to add it unless there's a specific
> reason. I don't think I2C buses need specific names, do they?

It is not strictly needed, but from a usability standpoint it is
terribly helpful. It serves to make it obvious to someone looking at
the device that it's _not_ an i2c bus associated with the main SoC.
If you don't include a number I believe that the i2c core will pick
the first available number.

It seems worth it to save a few people a few hours of head scratching.

...but this is your dts and if you think it's a terrible idea then
I'll remove it. It looks to be less critical on tegra than it is on
exynos (which has ~9 i2c busses, they are numbered in the user manual,
and if you have one set to "disable" in the dts then the tunnel will
end up getting a very confusing number).

-Doug
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