linux-kernel - [PATCH 5.11 016/306] gpiolib: Read "gpio-line-names" from a firmware node

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20210315135508.163678844@linuxfoundation.org>
Date:   Mon, 15 Mar 2021 14:51:19 +0100
From:   gregkh@...uxfoundation.org
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Marek Vasut <marex@...x.de>,
        Roman Guskov <rguskov@...electronics.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: [PATCH 5.11 016/306] gpiolib: Read "gpio-line-names" from a firmware node

From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>

commit b41ba2ec54a70908067034f139aa23d0dd2985ce upstream.

On STM32MP1, the GPIO banks are subnodes of pin-controller@...02000,
see arch/arm/boot/dts/stm32mp151.dtsi. The driver for
pin-controller@...02000 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@...02000 != pin-controller@...02000/gpio@...0*000.

The original code behaved correctly, as it extracted the "gpio-line-names"
from of_fwnode_handle(chip.of_node) = pin-controller@...02000/gpio@...0*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@...x.de>
Reported-by: Roman Guskov <rguskov@...electronics.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Tested-by: Marek Vasut <marex@...x.de>
Reviewed-by: Marek Vasut <marex@...x.de>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/gpio/gpiolib.c |   12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -365,22 +365,18 @@ static int gpiochip_set_desc_names(struc
  *
  * 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;
 
@@ -394,7 +390,7 @@ static int devprop_gpiochip_set_names(st
 	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");