On Fri, Jul 10, 2015 at 4:29 AM, Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx> wrote: > On 1 July 2015 at 19:36, Rob Herring <robherring2@xxxxxxxxx> wrote: >> On Wed, Jul 1, 2015 at 7:45 AM, Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx> wrote: >>> When an OF node has a pin range for its GPIOs, return -EPROBE_DEFER if >>> the pin controller isn't available. >>> >>> Otherwise, the GPIO range wouldn't be set at all unless the pin >>> controller probed always before the GPIO chip. >>> >>> With this change, the probe of the GPIO chip will be deferred and will >>> be retried at a later point, hopefully once the pin controller has been >>> registered and probed already. >> >> This will break cases where the pinctrl driver does not exist, but the >> DT contains pinctrl bindings. We can have similar problems already >> with clocks though. However, IMO this problem is a bit different in >> that pinctrl is more likely entirely optional while clocks are often >> required. You may do all pin setup in bootloader/firmware on some >> boards and not others. Of course then why put pinctrl in the DT in >> that case? They could be present just due to how chip vs. board dts >> files are structured. > > I see. My instinct tells me that it would be better if the gpio-ranges > property was set in the board dts, but I don't really know what each > mach does with its DTSs. > >> We could address this by simply marking the pin controller node >> disabled. However, ... >> >>> @@ -361,7 +361,7 @@ static void of_gpiochip_add_pin_range(struct gpio_chip *chip) >>> >>> pctldev = of_pinctrl_get(pinspec.np); >>> if (!pctldev) >>> - break; >>> + return -EPROBE_DEFER; >> >> But you cannot distinguish that case here. I think of_pinctrl_get >> needs to set the error code appropriately. > > Why not? I was thinking of just doing this before we call of_pinctrl_get(): > > if (!of_device_is_available(pinspec.np)) > continue; That is exactly what you need, but that should be of_pinctrl_get's responsibility to check, not the caller's. IIRC, this is the only user of of_pinctrl_get, so it should be just as easy to change. Rob -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
