gpio: swnode: compare the "undefined" swnode by its address, not name

[PATCH] gpio: swnode: compare the "undefined" swnode by its address, not name

Posted by Bartosz Golaszewski 1 month, 3 weeks ago

We know the address of the underlying remote software node referenced by
the GPIO property (if it is a software node). We don't need to compare
its name, we can compare its address which is more precise anyway.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
---
 drivers/gpio/gpiolib-swnode.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/gpio/gpiolib-swnode.c b/drivers/gpio/gpiolib-swnode.c
index b44f35d684590..54bad9e88fe5c 100644
--- a/drivers/gpio/gpiolib-swnode.c
+++ b/drivers/gpio/gpiolib-swnode.c
@@ -18,19 +18,18 @@
 
 #include <linux/gpio/consumer.h>
 #include <linux/gpio/driver.h>
+#include <linux/gpio/property.h>
 
 #include "gpiolib.h"
 #include "gpiolib-swnode.h"
 
-#define GPIOLIB_SWNODE_UNDEFINED_NAME "swnode-gpio-undefined"
-
 static struct gpio_device *swnode_get_gpio_device(struct fwnode_handle *fwnode)
 {
 	const struct software_node *gdev_node;
 	struct gpio_device *gdev;
 
 	gdev_node = to_software_node(fwnode);
-	if (!gdev_node || !gdev_node->name)
+	if (!gdev_node)
 		goto fwnode_lookup;
 
 	/*
@@ -38,7 +37,7 @@ static struct gpio_device *swnode_get_gpio_device(struct fwnode_handle *fwnode)
 	 * primarily used as a key for internal chip selects in SPI bindings.
 	 */
 	if (IS_ENABLED(CONFIG_GPIO_SWNODE_UNDEFINED) &&
-	    !strcmp(gdev_node->name, GPIOLIB_SWNODE_UNDEFINED_NAME))
+	    gdev_node == &swnode_gpio_undefined)
 		return ERR_PTR(-ENOENT);
 
 fwnode_lookup:
@@ -139,9 +138,7 @@ int swnode_gpio_count(const struct fwnode_handle *fwnode, const char *con_id)
  * A special node that identifies undefined GPIOs, this is primarily used as
  * a key for internal chip selects in SPI bindings.
  */
-const struct software_node swnode_gpio_undefined = {
-	.name = GPIOLIB_SWNODE_UNDEFINED_NAME,
-};
+const struct software_node swnode_gpio_undefined = { };
 EXPORT_SYMBOL_NS_GPL(swnode_gpio_undefined, "GPIO_SWNODE");
 
 static int __init swnode_gpio_init(void)
-- 
2.51.0

Re: [PATCH] gpio: swnode: compare the "undefined" swnode by its address, not name

Posted by Andy Shevchenko 1 month, 1 week ago

On Mon, Dec 15, 2025 at 04:46:24PM +0100, Bartosz Golaszewski wrote:
> We know the address of the underlying remote software node referenced by
> the GPIO property (if it is a software node). We don't need to compare
> its name, we can compare its address which is more precise anyway.

...

> -const struct software_node swnode_gpio_undefined = {
> -	.name = GPIOLIB_SWNODE_UNDEFINED_NAME,
> -};
> +const struct software_node swnode_gpio_undefined = { };

This will remove the name from sysfs, which may be informative.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] gpio: swnode: compare the "undefined" swnode by its address, not name

Posted by Bartosz Golaszewski 1 month, 3 weeks ago

On Mon, 15 Dec 2025 16:46:24 +0100, Bartosz Golaszewski wrote:
> We know the address of the underlying remote software node referenced by
> the GPIO property (if it is a software node). We don't need to compare
> its name, we can compare its address which is more precise anyway.
> 
> 

Applied, thanks!

[1/1] gpio: swnode: compare the "undefined" swnode by its address, not name
      commit: 6774a66d0e103d0e3e4c0f37dbd61946ec83edf0

Best regards,
-- 
Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

Re: [PATCH] gpio: swnode: compare the "undefined" swnode by its address, not name

Posted by Andy Shevchenko 1 month, 1 week ago

On Thu, Dec 18, 2025 at 12:27:11PM +0100, Bartosz Golaszewski wrote:
> 
> On Mon, 15 Dec 2025 16:46:24 +0100, Bartosz Golaszewski wrote:
> > We know the address of the underlying remote software node referenced by
> > the GPIO property (if it is a software node). We don't need to compare
> > its name, we can compare its address which is more precise anyway.
> 
> Applied, thanks!
> 
> [1/1] gpio: swnode: compare the "undefined" swnode by its address, not name
>       commit: 6774a66d0e103d0e3e4c0f37dbd61946ec83edf0

Okay, but still consider returning the name. The idea of comparing with
the address I agree with.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] gpio: swnode: compare the "undefined" swnode by its address, not name

Posted by Charles Keepax 1 month, 3 weeks ago

On Mon, Dec 15, 2025 at 04:46:24PM +0100, Bartosz Golaszewski wrote:
> We know the address of the underlying remote software node referenced by
> the GPIO property (if it is a software node). We don't need to compare
> its name, we can compare its address which is more precise anyway.
> 
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
> ---

Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Tested-by: Charles Keepax <ckeepax@opensource.cirrus.com>

Thanks,
Charles