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* [PATCH v1 1/1] gpiolib: Read "gpio-line-names" from a firmware node
@ 2021-03-05 12:02 Andy Shevchenko
  2021-03-05 12:11 ` Marek Vasut
                   ` (2 more replies)
  0 siblings, 3 replies; 18+ messages in thread
From: Andy Shevchenko @ 2021-03-05 12:02 UTC (permalink / raw)
  To: linux-gpio, linux-kernel
  Cc: Linus Walleij, Bartosz Golaszewski, Andy Shevchenko, Marek Vasut,
	Roman Guskov

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 <marex@denx.de>
Reported-by: Roman Guskov <rguskov@dh-electronics.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@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


^ permalink raw reply related	[flat|nested] 18+ messages in thread

end of thread, other threads:[~2021-04-10 13:18 UTC | newest]

Thread overview: 18+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-03-05 12:02 [PATCH v1 1/1] gpiolib: Read "gpio-line-names" from a firmware node Andy Shevchenko
2021-03-05 12:11 ` Marek Vasut
2021-03-05 12:24   ` Andy Shevchenko
2021-03-05 12:26     ` Marek Vasut
2021-03-07 13:55 ` Bartosz Golaszewski
2021-03-07 16:14   ` Andy Shevchenko
2021-03-08 11:45     ` Andy Shevchenko
2021-03-08 13:00       ` Bartosz Golaszewski
2021-03-15  9:01 ` Bartosz Golaszewski
2021-03-15 10:16   ` Andy Shevchenko
2021-03-15 12:50     ` Andy Shevchenko
2021-03-15 14:04       ` Bartosz Golaszewski
2021-03-15 14:34         ` Andy Shevchenko
2021-03-15 16:47           ` Bartosz Golaszewski
2021-03-15 17:04             ` Andy Shevchenko
2021-04-10  0:45               ` Marek Vasut
2021-04-10  9:06                 ` Bartosz Golaszewski
2021-04-10 13:18                   ` Marek Vasut

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