On Fri, Mar 5, 2021 at 1:03 PM Andy Shevchenko
<andriy.shevche...@linux.intel.com> wrote:
>
> 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")
> Reported-by: Marek Vasut <ma...@denx.de>
> Reported-by: Roman Guskov <rgus...@dh-electronics.com>
> Signed-off-by: Andy Shevchenko <andriy.shevche...@linux.intel.com>
> ---
> drivers/gpio/gpiolib.c | 12 ++++--------
> 1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index 3bc25a9c4cd6..ba88011cc79d 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -367,22 +367,18 @@ static int gpiochip_set_desc_names(struct gpio_chip *gc)
> *
> * Looks for device property "gpio-line-names" and if it exists assigns
> * GPIO line names for the chip. The memory allocated for the assigned
> - * names belong to the underlying software node and should not be released
> + * names belong to the underlying firmware node and should not be released
> * by the caller.
> */
> static int devprop_gpiochip_set_names(struct gpio_chip *chip)
> {
> struct gpio_device *gdev = chip->gpiodev;
> - struct device *dev = chip->parent;
> + struct fwnode_handle *fwnode = dev_fwnode(&gdev->dev);
> const char **names;
> int ret, i;
> int count;
>
> - /* GPIO chip may not have a parent device whose properties we
> inspect. */
> - if (!dev)
> - return 0;
> -
> - count = device_property_string_array_count(dev, "gpio-line-names");
> + count = fwnode_property_string_array_count(fwnode, "gpio-line-names");
> if (count < 0)
> return 0;
>
> @@ -396,7 +392,7 @@ static int devprop_gpiochip_set_names(struct gpio_chip
> *chip)
> if (!names)
> return -ENOMEM;
>
> - ret = device_property_read_string_array(dev, "gpio-line-names",
> + ret = fwnode_property_read_string_array(fwnode, "gpio-line-names",
> names, count);
> if (ret < 0) {
> dev_warn(&gdev->dev, "failed to read GPIO line names\n");
> --
> 2.30.1
>
Hi Andy!
Unfortunately while this may fix the particular use-case on STM32, it
breaks all other users as the 'gpio-line-names' property doesn't live
on dev_fwnode(&gdev->dev) but on dev_fwnode(chip->parent).
How about we first look for this property on the latter and only if
it's not present descend down to the former fwnode?
Bart
