On Fri, Mar 10, 2023 at 02:38:10PM +0100, Benjamin Tissoires wrote: > While trying to set up an SSDT override for a USB-2-I2C chip [0], > I realized that the function acpi_gpiochip_find() was using the parent > of the gpio_chip to do the ACPI matching. > > This works fine on my Ice Lake laptop because AFAICT, the DSDT presents > the PCI device INT3455 as the "Device (GPI0)", but is in fact handled > by the pinctrl driver in Linux. > The pinctrl driver then creates a gpio_chip device. This means that the > gc->parent device in that case is the GPI0 device from ACPI and everything > works. > > However, in the hid-cp2112 case, the parent is the USB device, and the > gpio_chip is directly under that USB device. Which means that in this case > gc->parent points at the USB device, and so we can not do an ACPI match > towards the GPIO device. > > I think it is safe to resolve the ACPI matching through the fwnode > because when we call gpiochip_add_data(), the first thing it does is > setting a proper gc->fwnode: if it is not there, it borrows the fwnode > of the parent. > > So in my Ice Lake case, gc->fwnode is the one from the parent, meaning > that the ACPI handle we will get is the one from the GPI0 in the DSDT > (the pincrtl one). And in the hid-cp2112 case, we get the actual > fwnode from the gpiochip we created in the HID device, making it working. Pushed to my review and testing queue, thanks! -- With Best Regards, Andy Shevchenko
