Hi Rob, On Mon, Sep 9, 2024 at 3:40 PM Rob Herring <robh@xxxxxxxxxx> wrote: > On Mon, Sep 9, 2024 at 8:31 AM Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote: > > On Mon, Sep 9, 2024 at 3:07 PM Rob Herring <robh@xxxxxxxxxx> wrote: > > > On Mon, Sep 9, 2024 at 5:58 AM Wolfram Sang > > > <wsa+renesas@xxxxxxxxxxxxxxxxxxxx> wrote: > > > > > > > > Most I2C controllers do not have a dedicated pin for SMBus Alerts. Allow > > > > them to define a GPIO as a side-channel. > > > > > > Most GPIOs are also interrupts, so shouldn't the existing binding be > > > sufficient? The exception is if the GPIO needs to be polled. > > > > If the GPIO pin supports multiple functions, it must be configured as > > a GPIO first. devm_gpiod_get() takes care of that. Just calling > > request_irq() does not. In addition, the mapping from GPIO to IRQ > > number may not be fixed, e.g. in case the GPIO controller supports > > less interrupt inputs than GPIOs, and needs to map them when requested. > > All sounds like Linux problems... ;-) > > See also the different handling of interrupts and gpios by gpio-keys. > > I believe "gpios" is what was originally supported, but now it is > preferred if GPIOs are used as interrupts then we use interrupts in > DT. You really do not want to use gpio-keys with interrupts, unless you have no choice. Some shortcomings are outlined in "[PATCH RFC 3/3] Input: gpio-keys - Fix ghost events with both-edge irqs" [1]. They do not matter for SMBALERT, though. [1] https://lore.kernel.org/r/356b31ade897af77a06d6567601f038f56b3b2a2.1638538079.git.geert+renesas@xxxxxxxxx Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
