P1010: How to do pin muxing for P1010RDB in linux kernel

[nobelsharanyanj]

Hi,

How to do pin muxing for the board p1010? what are the files I need to check?

[ufedor]

> Is there any standard way to define in device tree regarding pin muxing?

No. This has to be done in U-Boot.

[scottwood]

Actually, there is.  See Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt

Currently we usually handle this in U-Boot, but putting it in the device tree would be better, as it could allow Linux to dynamically reconfigure.

[ufedor]

Please explain which exactly "pin muxing" and "board p1010" are in question.

[nobelsharanyanj]

Hi ufedor,

I am using P1010 rev 2, custom board.

I wish to use GPIO[6:9] instead of SPI,

GUTS_PMUXCR1 by default expose to SPI signal.

I like to know what is the suitable way of modifying the register to support my need.

Thanks

[ufedor]

It is needed to set GUTS_PMUXCR1[SPI]=0b10 in the p1010rdb.c

[nobelsharanyanj]

ok,

Where does "GUTS_PMUXCR1" defined in kernel.

Thanks

[ufedor · Accepted solution]

The "p1010rdb.c" is U-Boot component.

[nobelsharanyanj]

ok, I will look into uboot too,

In kernel,

compatible = "fsl,p1010-guts"; is been defined in "arch/powerpc/boot/dts/fsl/p1010si-post.dtsi".

That mean we can use device tree to get io_mem of that structure and we can re modify it in arch/powerpc/platforms/85xx/p1010rdb.c

Is there any standard way to define in device tree regarding pin muxing? so that I have kernel image common, for which I can support two or more board with device tree alone.