Re: [PATCH 5.11 12/31] gpiolib: Read "gpio-line-names" from a firmware node

From: Marek Vasut
Date: Fri Mar 19 2021 - 08:28:16 EST


On 3/19/21 1:19 PM, Greg Kroah-Hartman wrote:
From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>

[ Upstream commit b41ba2ec54a70908067034f139aa23d0dd2985ce ]

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.

I think we agreed to drop this one for now before, see
[PATCH 5.10 081/290] gpiolib: Read "gpio-line-names" from a firmware node
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