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: > > On Tue, Oct 23, 2012 at 10:02 PM, Dmitry Torokhov > > <dmitry.torokhov@xxxxxxxxx> wrote: > > > > > 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
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