On Wed, 16 May 2018, Amelie DELAUNAY wrote:

On 05/16/2018 04:20 PM, Linus Walleij wrote:

quoted

On Wed, May 9, 2018 at 9:56 AM, Amelie DELAUNAY [off-list ref] wrote:

quoted

Indeed, stmfx has other functions than GPIO. But, after comments done
here: [1] and there: [2], it has been decided to move MFD parent/GPIO
child drivers into a single PINCTRL/GPIO driver because of the following
reasons:
- Other stmfx functions (IDD measurement and TouchScreen controller) are
not used on any of the boards using an stmfx and supported by Linux, so
no way to test these functions, and no need to maintain them while they
are not being used.
- But, in the case a new board will use more than GPIO function on
stmfx, the actual implementation allow to easily extract common init
part of stmfx and put it in an MFD driver.

So I could remove gpio sub-node and put its contents in stmfx node and
keep single PINCTRL/GPIO driver for the time being.
Please advise,

I would normally advice to use the right modeling from the start, create
the MFD driver and spawn the devices from there. It is confusing
if the layout of the driver(s) doesn't really match the layout of the
hardware.

I understand that it is a pain to write new MFD drivers to get your
things going and it would be "nice to get this working really quick
now" but in my experience it is better to do it right from the start.

Hi Linus,

Thanks for your advice. I understand the point.
So, the right modeling would be to:
- create an MFD driver with the common init part of stmfx
- remove all common init part of stmfx-pinctrl driver and keep only all 
gpio/pinctrl functions.

I will not develop the other stmfx functions (IDD measurement driver and 
TouchScreen controller driver) because, as explained ealier, they are 
not used on any of the boards using an stmfx and supported by Linux, so 
no way to test these functions, and no need to maintain them while they 
are not being used.

Lee, are you OK with that ?

I missed a lot of this conversation I think, but from what I've read,
it sounds fine.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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