Hi,

On Wed, Oct 24, 2012 at 09:18:01AM -0700, Dmitry Torokhov wrote:

On Wed, Oct 24, 2012 at 02:54:23PM +0200, Linus Walleij wrote:

quoted

On Tue, Oct 23, 2012 at 10:02 PM, Dmitry Torokhov
[off-list ref] wrote:

quoted

I have seen just in a few days 3 or 4 drivers having exactly the same
change - call to devm_pinctrl_get_select_default(), and I guess I will
receive the same patches for the rest of input drivers shortly.
This suggests that the operation is done at the wrong level. Do the
pin configuration as you parse DT data, the same way you set up i2c
devices registers in of_i2c.c, and leave the individual drivers that do
not care about specifics alone.

Exactly this can be done with pinctrl hogs.

The problem with that is that it removes the cross-reference
between the device and it's pinctrl handle (also from the device
tree). Instead the pinctrl handle gets referenced to the pin controller
itself. So from a modelling perpective this looks a bit ugly.

So we have two kinds of ugly:

- Sprinke devm_pinctrl_get_select_default() over all drivers
  which makes pinctrl handles properly reference their devices

- Use hogs and loose coupling between pinctrl handles and their
  devices

A third alternative as outlined is to use notifiers and some
resource core in drivers/base/*

OK, so with drivers/base/, have you considered doing default pinctrl
selection in bus's probe() methods? Yo would select the default
configuration before starting probing the device and maybe select idle
when probe fails or device is unbound? That would still keep the link
between device object and pinctrl and there less busses than device
drivers out there.

it starts to become confusing after a while. I mean, there's a reason
why all drivers explictly call pm_runtim_enable(), right ?

From a first thought, one could think of just yanking that into bus'
probe() as you may suggest, but sometimes the device is already enabled,
so we need extra tricks:

pm_runtime_set_active();
pm_runtime_enable();
pm_runtime_get();

the same could happen with pinctrl eventually. What if a device needs to
do something else (an errata fix as an example) before requesting
pinctrl's default state ?

-- 
balbi