On Wed, 11 Mar 2026 12:44:31 +0100, Geert Uytterhoeven <[email protected]> said: > Hi Tzung-Bi, > > On Mon, 23 Feb 2026 at 07:17, Tzung-Bi Shih <[email protected]> wrote: >> To make the intent clear, access `gpio_bus_type` only when it's ready in >> gpiochip_setup_dev(). >> >> Reviewed-by: Linus Walleij <[email protected]> >> Signed-off-by: Tzung-Bi Shih <[email protected]> > > Thanks for your patch, which is now commit cc11f4ef666fbca0 ("gpio: > Access `gpio_bus_type` in gpiochip_setup_dev()") in gpio/gpio/for-next. > >> --- a/drivers/gpio/gpiolib.c >> +++ b/drivers/gpio/gpiolib.c >> @@ -901,6 +901,8 @@ static int gpiochip_setup_dev(struct gpio_device *gdev) >> struct fwnode_handle *fwnode = dev_fwnode(&gdev->dev); >> int ret; >> >> + gdev->dev.bus = &gpio_bus_type; >> + >> /* >> * If fwnode doesn't belong to another device, it's safe to clear its >> * initialized flag. >> @@ -1082,7 +1084,6 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, >> void *data, >> * then make sure they get free():ed there. >> */ >> gdev->dev.type = &gpio_dev_type; >> - gdev->dev.bus = &gpio_bus_type; >> gdev->dev.parent = gc->parent; >> device_set_node(&gdev->dev, gpiochip_choose_fwnode(gc)); >> > > Postponing this assignment does have an impact on early > messages. E.g. on RBTX4927: > > -gpio gpiochip0: Static allocation of GPIO base is deprecated, use > dynamic allocation. > + gpiochip0: Static allocation of GPIO base is deprecated, use > dynamic allocation. > > Or with CONFIG_DEBUG_GPIO=y, e.g. on BeagleBone black: > > -gpio gpiochip0: (gpio-0-31): created GPIO range 0->7 ==> > 44e10800.pinmux PIN 0->7 > -gpio gpiochip0: (gpio-0-31): created GPIO range 8->11 ==> > 44e10800.pinmux PIN 90->93 > -gpio gpiochip0: (gpio-0-31): created GPIO range 12->27 ==> > 44e10800.pinmux PIN 12->27 > -gpio gpiochip0: (gpio-0-31): created GPIO range 28->31 ==> > 44e10800.pinmux PIN 30->33 > + gpiochip0: (gpio-0-31): created GPIO range 0->7 ==> > 44e10800.pinmux PIN 0->7 > + gpiochip0: (gpio-0-31): created GPIO range 8->11 ==> > 44e10800.pinmux PIN 90->93 > + gpiochip0: (gpio-0-31): created GPIO range 12->27 ==> > 44e10800.pinmux PIN 12->27 > + gpiochip0: (gpio-0-31): created GPIO range 28->31 ==> > 44e10800.pinmux PIN 30->33 > [...] > > Note the spaces at the beginning of the printed lines. > Reverting the commit re-adds the "gpio" prefix. >
As per the comment in gpiochip_add_data_with_key(): we may end up with a functional chip before gpiochip_setup_dev() is called and so before we assign the bus type. dev_printk() helpers only read the name field of the bus type so it should be safe, I don't see anyone else accessing it before we register it. I think it makes sense to revert this commit. Tzung-Bi: what do you think? Bart
