Re: [PATCH v3] gpiolib: fix allocation of mixed dynamic/static GPIOs

[Linus Walleij]

On Thu, May 4, 2023 at 8:04 AM Andreas Kemnade <andreas@xxxxxxxxxxxx> wrote:

> If static allocation and dynamic allocation GPIOs are present,
> dynamic allocation pollutes the numberspace for static allocation,
> causing static allocation to fail.
> Enforce dynamic allocation above GPIO_DYNAMIC_BASE.
>
> Seen on a GTA04 when omap-gpio (static) and twl-gpio (dynamic)
> raced:
> [some successful registrations of omap_gpio instances]
> [    2.553833] twl4030_gpio twl4030-gpio: gpio (irq 145) chaining IRQs 161..178
> [    2.561401] gpiochip_find_base: found new base at 160
> [    2.564392] gpio gpiochip5: (twl4030): added GPIO chardev (254:5)
> [    2.564544] gpio gpiochip5: registered GPIOs 160 to 177 on twl4030
> [...]
> [    2.692169] omap-gpmc 6e000000.gpmc: GPMC revision 5.0
> [    2.697357] gpmc_mem_init: disabling cs 0 mapped at 0x0-0x1000000
> [    2.703643] gpiochip_find_base: found new base at 178
> [    2.704376] gpio gpiochip6: (omap-gpmc): added GPIO chardev (254:6)
> [    2.704589] gpio gpiochip6: registered GPIOs 178 to 181 on omap-gpmc
> [...]
> [    2.840393] gpio gpiochip7: Static allocation of GPIO base is deprecated, use dynamic allocation.
> [    2.849365] gpio gpiochip7: (gpio-160-191): GPIO integer space overlap, cannot add chip
> [    2.857513] gpiochip_add_data_with_key: GPIOs 160..191 (gpio-160-191) failed to register, -16
> [    2.866149] omap_gpio 48310000.gpio: error -EBUSY: Could not register gpio chip
>
> On that device it is fixed invasively by
> commit 92bf78b33b0b4 ("gpio: omap: use dynamic allocation of base")
> but let's also fix that for devices where there is still
> a mixture of static and dynamic allocation.
>
> Fixes: 7b61212f2a07 ("gpiolib: Get rid of ARCH_NR_GPIOS")
> Signed-off-by: Andreas Kemnade <andreas@xxxxxxxxxxxx>
> Reviewed-by: <christophe.leroy@xxxxxxxxxx>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>

Looks good to me!
Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>

Yours,
Linus Walleij