On 29/07/2014 at 10:00:17 +0200, Boris Brezillon wrote : > Hi Alexandre, > > > While this solves the particular issue Jiří is seeing, this will not > > solve the case where PA14 (CS0) is not used by the spi driver at all. It > > will remained muxed as CS0 and toggle when the spi master needs to > > access CS0 until another driver muxes it to something else. I still > > believe we should explicitly ask pinctrl to mux them as gpios. > > > > Do we really care about this case ? > After all, if a given pin needs a specific muxing during kernel boot > (i.e. a pin connected to a gpio-led that needs to stay in its previous > state or a pin connected to the reset line of a device that needs to > stay up and running during kernel boot) the bootloader/bootstrap should > have muxed this pin appropriately before booting the kernel. > Yeah, you are right. > What do you mean by "we should explicitly ask pinctrl to mux them as > gpios" ? > Do you mean configuring all the pins as GPIOs when the pin controller is > probed, or just adding a new pinctrl state configuring the pin as an > output GPIO and reference it in the pinctrl-0 property of the spi > controller. > > If the former, you'll break devices that needs their pins to stay in > the state they were during the bootloader/boostrap phase. > The latter won't work if the pin you request as GPIO is later requested > by another device (which, if I'm correct, is exactly the case you're > trying to solve). > Again you are right, let's not care about that use case. I still feel that the pinctrl-0 property has to be filled correctly. -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- 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
