Re: [PATCH] Revert "gpiolib: generalize devprop_gpiochip_set_names() for device properties"

[Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>]

On Fri, Mar 05, 2021 at 11:51:02AM +0100, Marek Vasut wrote:
> On 3/5/21 11:44 AM, Andy Shevchenko wrote:
> > On Fri, Mar 05, 2021 at 12:09:56AM +0100, Marek Vasut wrote:
> > > This reverts 7cba1a4d5e162 ("gpiolib: generalize devprop_gpiochip_set_names()
> > > for device properties") because this breaks OF "gpio-line-names" behavior on
> > > STM32MP1 platform.
> > > 
> > > On STM32MP1, the GPIO banks are subnodes of pin-controller@50002000, see
> > > arch/arm/boot/dts/stm32mp151.dtsi. The driver for pin-controller@50002000
> > > is in drivers/pinctrl/stm32/pinctrl-stm32.c and iterates over all of its DT
> > > subnodes when registering each GPIO bank gpiochip. Each gpiochip has:
> > > - gpio_chip.parent = dev where dev is the device node of the pin controller
> > > - gpio_chip.of_node = np which is the OF node of the GPIO bank
> > > Therefore, dev_fwnode(chip->parent) != of_fwnode_handle(chip.of_node) , i.e.
> > > pin-controller@50002000 != pin-controller@50002000/gpio@5000*000.
> > > 
> > > The original code behaved correctly, as it extracted the "gpio-line-names"
> > > from of_fwnode_handle(chip.of_node) = pin-controller@50002000/gpio@5000*000.
> > > This patch reinstates the original correct behavior.
> > 
> > > Signed-off-by: Marek Vasut <marex@xxxxxxx>
> > > Reported-by: Roman Guskov <rguskov@xxxxxxxxxxxxxxxxxx>
> > 
> > Thanks for the report and a fix!
> > However I think the revert is not an option. We may do much better.
> 
> The revert is pretty much also the minimal change to reinstate the original
> behavior. What better option do you have in mind, please do elaborate in
> detail. Thank you.

Patch has been tested and just sent. Please test it on your side.

-- 
With Best Regards,
Andy Shevchenko