On 11/29/2017 09:02 AM, Tony Lindgren wrote: > * Linus Walleij <linus.walleij@xxxxxxxxxx> [171129 13:03]: >> On Fri, Nov 3, 2017 at 12:15 AM, Florian Fainelli <f.fainelli@xxxxxxxxx> wrote: >> >>> Some platforms (e.g: Broadcom STB: BMIPS_GENERIC/ARCH_BRCMSTB) will lose >>> their register contents when entering their lower power state. In such a >>> case, the pinctrl-single driver that is used will not be able to restore >>> the power states without telling the core about it and having >>> pinctrl_select_state() check for that. >>> >>> This patch adds a new optional boolean property that Device Tree can >>> define in order to obtain exactly that and having the core pinctrl code >>> take that into account. >>> >>> Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx> >> >> Florian, I'm really sorry for losing track of this patch set, it's >> important stuff and I see why systems are dependent on something >> like this. >> >> Tony: can you look at this from a pinctrl-single point of view? >> This is the intended consumer: pinctrl-single users that lose the >> hardware state over suspend/resume. >> >> How do you see this working with other pinctrl-single users? > > Hmm well typically a device driver that loses it's context just does > save and restore of the registers in runtime PM suspend/resume > as needed. In this case it would mean duplicating the state for > potentially for hundreds of registers.. So using the existing > state in the pinctrl subsystem totally makes sense for the pins. > > Florian do you have other reasons why this should be done in the > pinctrl framework instead of the driver? Might be worth describing > the reasoning in the patch descriptions :) The pinctrl provider driver that I am using is pinctrl-single, which has proper suspend/resume callbacks but those are not causing any HW programming to happen because of the (p->state == state) check, hence this patch series. > > So as long as the pinctrl framework state is used to restore the > state by the pinctrl driver instead of the pinctrl consumer drivers, > I don't have issues with this patchset. So probably just improving > the patch messages a bit should do it. > > FYI, on omaps, the PRCM hardware saves and restores the pinctrl > state so this has not been so far an issue. > > Regards, > > Tony > > -- Florian -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
