Messages in this thread | | | Date | Fri, 6 Oct 2023 16:14:57 +0300 | From | Andy Shevchenko <> | Subject | Re: [RFC/RFT PATCH] gpiolib: reverse-assign the fwnode to struct gpio_chip |
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On Fri, Oct 06, 2023 at 01:51:47PM +0200, Bartosz Golaszewski wrote: > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> > > struct gpio_chip is not only used to carry the information needed to > set-up a GPIO device but is also used in all GPIOLIB callbacks and is > passed to the matching functions of lookup helpers. > > In that last case, it is currently impossible to match a GPIO device by > fwnode unless it was explicitly assigned to the chip in the provider > code.
That's expected behaviour.
> If the fwnode is taken from the parent device, the pointer in > struct gpio_chip will remain NULL.
> If we have a parent device but gc->fwnode was not assigned by the > provider, let's assign it ourselves so that lookup by fwnode can work in > all cases.
I don't think this is a good change. We paper over the real issue where we and callers need to understand what they are looking for.
...
> This is something that Dipen reported with one of the tegra drivers where > a GPIO lookup by fwnode does not work because the fwnode pointer in struct > gpio_chip is NULL. This patch addresses this use-case.
I am not sure I understand the problem here. All these should have been addressed already, no?
So, the GPIOLIB should use dev_fwnode(&gdev->dev) inside it, outside it the GPIO drivers are free to use gc->fwnode as long as they understand the lifetime of the respective object.
-- With Best Regards, Andy Shevchenko
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