pxa27x and pinctrl-single

[Haojian Zhuang]

On 8 June 2013 01:41, Mike Dunn <mikedunn at newsguy.com> wrote:
> On 06/07/2013 08:16 AM, Haojian Zhuang wrote:
>>
>
> [...]
>
>
>> Since you need to configure both GPDRx and GAFRx. If we are talking
>> pinctrl-single
>> as reference, we can make it work by this way.
>>
>> We need to define two pinmux controllers. One is for GPDRx, and the
>> other is for GAFRx.
>> Both of them need to support pinctrl-single,bits property. For any
>> alternate pins in DTS,
>> we could include these two pins from two pinmux controllers. What's
>> your opinion?
>
>
> Are you are suggesting that the dts file can be defined such that the desired
> values are written to GAFR and GPDR, without having to make any changes to the
> pinctrl-single driver code?  If I understand correctly, we would be defining two
> "pins" in the device tree for each actual pin.  That seems very ugly.
>
> I was thinking that pinctrl-single could be modified to support multiple
> reg/value/mask pairs for each pin listed in the pinctrl-single,bits property.
> There is a comment at the top of pcs_parse_one_pinctrl_entry() that seems to
> suggest the possibility...

We only support continuous register offset in pinctrl-single driver.
GPDRx is in range of 0x40e0000c~0x40e0010c, GAFRx is in range of
0x40e00054~0x40e00070.

So I suggest you to split them as two pinmux controller. If you define them into
one pinmux controler, it's also OK. But they are still two pins in the on pinmux
controller. And you should avoid to access those spare pins in the middle.

I don't suggest you to support multiple reg/value/mask pairs for each pin in
pinctrl-single driver. It's too complex. It already exceeds the design scope
of the pinctrl-single driver.

Regards
Haojian
>
>  * Note that this binding currently supports only sets of one register + value.
>
> I am still learning pinctrl and devicetree and studying the driver, so I am not
> adament about anything at this point.  Guidance appreciated!
>
> Thanks,
> Mike