Re: [PATCH V4 1/5] DT: mfd: add device-tree binding doc fro PMIC max77620/max20024

From: Lee Jones
Date: Wed Jan 27 2016 - 02:24:43 EST

On Tue, 26 Jan 2016, Laxman Dewangan wrote:

> On Tuesday 26 January 2016 08:28 PM, Lee Jones wrote:
> >On Mon, 25 Jan 2016, Laxman Dewangan wrote:
> >
> >>Hmm. I describe the boolean and tristate only. Do I need to define
> >>type for integer,string also?
> >I wouldn't describe any of them. It's normally pretty obvious which
> >properties are boolean by the lack of required cell description.
> >
> Rob suggested to use the type also for Boolean and tristate. I think
> it is good to have for all places that what type of values are
> valid.

It's fine, and some people do describe them. I've just never seen the
point, especially if you have a nice example of their use in the
document. But if you insist, please ensure you are consistent, so
*all* bools need to be described. That is not currently the case.

> >>>>+The property for fps child nodes as:
> >>>>+Required properties:
> >>>>+ -reg: FPS number like 0, 1, 2 for FPS0, FPS1 and FPS2 respectively.
> >>>I'm surprised Rob Acked this. We don't usually do device numbers in DT.
> >>What is best way to make the child node for FPS and differentiate FPS0,1, 2?
> >>What is your suggestion here?
> >There are lots of ways you can solve this and so many examples of
> >others doing so. I suggest you have a look at some DTS files and
> >figure it out. One possible solution is to use different compatible
> >strings.
> Here, I think I can go similar to regulators where child node name
> identifies the regulators.
> fps-config {
> fps0 {
> maxim,fps-time-period-us = <1280>;
> maxim,fps-enable-input = <FPS_EN_SRC_EN0>;
> };
> fps1 {
> maxim,fps-time-period-us = <2560>;
> maxim,fps-enable-input = <FPS_EN_SRC_EN1>;
> };
> fps2 {
> maxim,fps-time-period-us = <640>;
> maxim,fps-enable-input = <FPS_EN_SRC_SW>;
> };
> };
> So node name gives the FPS name.

That is also an acceptable means to solve the issue.

As I said, there are many ways to skin a cat.

> >>>+Pinmux and GPIO:
> >>>+===============
> >>>I think this whole section needs moving to ../pinctrl and needs to be
> >>>reviewed by Linus W.
> >>Is this mean I need to create DT binding doc for the each subsystem
> >>differently?
> >>Actually during AS3722, I had different understanding to have single file.
> >Yes, that way you have each of the the subsystem experts review your
> >documentation. You can then link to them from this document.
> OK, I will add different dt binding doc in respective driver and
> squash that with respected submodule drivers.

Lee Jones
Linaro STMicroelectronics Landing Team Lead â Open source software for ARM SoCs
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