Re: [PATCH stable] gpiolib: Read "gpio-line-names" from a firmware node

[Greg Kroah-Hartman]

On Sat, Apr 10, 2021 at 11:09:19AM +0200, Bartosz Golaszewski wrote:
> From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> 
> 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.
> 
> To achieve the same behaviour, read property from the firmware node.
> 
> Fixes: 7cba1a4d5e162 ("gpiolib: generalize devprop_gpiochip_set_names() for device properties")
> Cc: stable@xxxxxxxxxxxxxxx
> Reported-by: Marek Vasut <marex@xxxxxxx>
> Reported-by: Roman Guskov <rguskov@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Tested-by: Marek Vasut <marex@xxxxxxx>
> Reviewed-by: Marek Vasut <marex@xxxxxxx>
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
> ---
> Hi Greg,
> 
> This patch somehow got lost and never made its way into stable. Could you
> please apply it?

This has been added and removed more times than I can remember already.

Are you all _SURE_ this is safe for a stable kernel release?  Look in
the archives for complaints when we added this in the past.

thanks,

greg k-h