Re: [PATCH] ARM: dt: tegra: ventana: define pinmux for ddc

From: Mark Zhang
Date: Mon Oct 22 2012 - 03:35:50 EST

On 10/19/2012 11:48 PM, Stephen Warren wrote:
On 10/18/2012 11:58 PM, Mark Zhang wrote:
Define pinmux for DDC. The DDC pinmux in Ventana is 2 pins in I2C2.

+++ b/arch/arm/boot/dts/tegra20-ventana.dts

- ddc {
- nvidia,pins = "ddc", "owc", "spdi", "spdo",
- "uac";
- nvidia,function = "rsvd2";
- };

So that removes the entries for 5 pin groups, yet below, entries are
only added for the ddc and pta pingroups, so the other 4 pin groups
become unconfigured.

Right. So I think it should be changed to:

owc {
nvidia,pins = "owc", "spdi", "spdo", "uac";
nvidia,function = "rsvd2";

Is this right?

+ state_i2cmux_ddc: pinmux_i2cmux_ddc {
+ ddc {
+ nvidia,pins = "ddc";
+ nvidia,function = "i2c2";
+ };
+ pta {
+ nvidia,pins = "pta";
+ nvidia,function = "rsvd4";
+ };

Does this actually work? The pta pingroup is configured by the "hog"
pinctrl state of the pinctrl node itself, so this state should fail to
be applied since it attempts to touch the same pingroup.

I know little about kernel pinctrl subsystem. After reading some docs and codes, I think what you mean is, in Ventana's pinmux configuration, pta pingroup has been defined as "hdmi" function and this can't be changed(non-dynamic pinmuxing).
So I want to know why we have defined pta pingroup as hdmi function?
Can we remove this definition to make the i2cmux above working?

+ i2cmux {
+ i2c@1 {
+ reg = <1>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+ smart-battery@b {
+ compatible = "ti,bq24617", "smart-battery-1.1";
+ reg = <0xb>;
+ ti,i2c-retry-count = <2>;
+ ti,poll-retry-count = <10>;
+ };

That wasn't there before. Does that device actually exist on Ventana?
Adding it should be a separate patch if so, since this one is just about
introducing the I2C mux, not adding an SBS device. Was this all just
cut/paste from Seaboard without validation?

Yes, I didn't validate this. Actually, I don't know how to validate. I have no idea about SBS device. But I have checked the schematic of Ventana and it has this "bq24617" battery charge controller(for seaboard, it's bq20z75).
So I agree with you not to include this part in the patch.
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