Hi Uwe, On 06/14/2016 01:03 PM, Uwe Kleine-König wrote: > Traditionally the n-th gpio device probed by the omap gpio driver got > the gpio number range [n*32 .. n*32+31]. > When order of the devices probed by the driver changes (which can happen > already now when some devices have a pinctrl and so the first probe > attempt returns -ENODEV) the numbering changes. > > To ensure a deterministical numbering use of_alias_get_id to determine > the number base for a given device. If no respective alias exists fall > back to the traditional numbering. > > For the unusual case where only a part of the gpio devices have a > matching alias some of them might fail to probe. But if none of them has > an alias or all, there is no conflict which should be good enough to > maintain backward compatibility. > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> > --- > Hello, > > if you're happy with this patch I can follow up and add the respective > aliases to the device trees. > Thanks for the patch. I have no objection to the idea of the patch, but there are some comments. > > drivers/gpio/gpio-omap.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c > index b98ede78c9d8..6814245a54aa 100644 > --- a/drivers/gpio/gpio-omap.c > +++ b/drivers/gpio/gpio-omap.c > @@ -1034,6 +1034,7 @@ static int omap_gpio_chip_init(struct gpio_bank *bank, struct irq_chip *irqc) > static int gpio; > int irq_base = 0; > int ret; > + int gpio_alias_id; > > /* > * REVISIT eventually switch from OMAP-specific gpio structs > @@ -1056,6 +1057,17 @@ static int omap_gpio_chip_init(struct gpio_bank *bank, struct irq_chip *irqc) > bank->chip.label = "gpio"; > bank->chip.base = gpio; I think, the gpio base correction should be done here > } > + > + /* > + * Traditionally the base is given out in first-come-first-serve order. > + * This might shuffle the numbering of gpios if the probe order changes. > + * So make the base deterministical if the device tree specifies alias > + * ids. > + */ > + gpio_alias_id = of_alias_get_id(bank->chip.of_node, "gpio"); > + if (gpio_alias_id >= 0) > + bank->chip.base = bank->width * gpio_alias_id; > + Unfortunately, this driver is still used by non-DT platforms, so above code will break build if !OF && !OF_GPIO I think, right way would be to get alias_id in .probe(), then calc base and save it in struct gpio_bank. Then use it here to fixup GPIO base if positive. > bank->chip.ngpio = bank->width; > > ret = gpiochip_add_data(&bank->chip, bank); > -- regards, -grygorii -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
