[PATCH v2 1/3] bcma: gpio: Add and register software node for GPIO controller

We want to convert the legacy gpio-keys platform device on BCM47XX
boards to use software nodes. To do this properly and allow
referencing the GPIO controller by address rather than relying on
name-based matching (which is being removed from the gpiolib core),
we need to associate the GPIO controller with a software node.

Introduce bcma_gpio_swnode, register it if the device does not
already have a firmware node, and associate it with the gpio_chip.

Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Dmitry Torokhov <[email protected]>
---
 drivers/bcma/driver_gpio.c | 43 +++++++++++++++++++++++++++++++++++++------
 include/linux/bcma/bcma.h  |  2 ++
 2 files changed, 39 insertions(+), 6 deletions(-)

diff --git a/drivers/bcma/driver_gpio.c b/drivers/bcma/driver_gpio.c
index 658c7e2ac8bf..ea45222f2fa0 100644
--- a/drivers/bcma/driver_gpio.c
+++ b/drivers/bcma/driver_gpio.c
@@ -19,6 +19,11 @@
 
 #define BCMA_GPIO_MAX_PINS	32
 
+const struct software_node bcma_gpio_swnode = {
+	.name = "bcma-gpio",
+};
+EXPORT_SYMBOL_GPL(bcma_gpio_swnode);
+
 static int bcma_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
 {
 	struct bcma_drv_cc *cc = gpiochip_get_data(chip);
@@ -190,7 +195,20 @@ int bcma_gpio_init(struct bcma_drv_cc *cc)
 	chip->direction_input	= bcma_gpio_direction_input;
 	chip->direction_output	= bcma_gpio_direction_output;
 	chip->parent		= bus->dev;
-	chip->fwnode		= dev_fwnode(&cc->core->dev);
+
+	/*
+	 * Register software node only for the host SoC bus, unless there is
+	 * already a firmware node assigned. There is only one SoC instance
+	 * in the system, so there are no concerns with registration conflicts.
+	 */
+	if (bus->hosttype == BCMA_HOSTTYPE_SOC && !dev_fwnode(&cc->core->dev)) {
+		err = software_node_register(&bcma_gpio_swnode);
+		if (err)
+			return err;
+		chip->fwnode = software_node_fwnode(&bcma_gpio_swnode);
+	} else {
+		chip->fwnode = dev_fwnode(&cc->core->dev);
+	}
 
 	switch (bus->chipinfo.id) {
 	case BCMA_CHIP_ID_BCM4707:
@@ -219,20 +237,33 @@ int bcma_gpio_init(struct bcma_drv_cc *cc)
 
 	err = bcma_gpio_irq_init(cc);
 	if (err)
-		return err;
+		goto err_unregister_swnode;
 
 	err = gpiochip_add_data(chip, cc);
-	if (err) {
-		bcma_gpio_irq_exit(cc);
-		return err;
-	}
+	if (err)
+		goto err_irq_exit;
 
 	return 0;
+
+err_irq_exit:
+	bcma_gpio_irq_exit(cc);
+err_unregister_swnode:
+	if (bus->hosttype == BCMA_HOSTTYPE_SOC &&
+	    chip->fwnode && is_software_node(chip->fwnode)) {
+		software_node_unregister(&bcma_gpio_swnode);
+		chip->fwnode = NULL;
+	}
+	return err;
 }
 
 int bcma_gpio_unregister(struct bcma_drv_cc *cc)
 {
 	bcma_gpio_irq_exit(cc);
 	gpiochip_remove(&cc->gpio);
+	if (cc->core->bus->hosttype == BCMA_HOSTTYPE_SOC &&
+	    cc->gpio.fwnode && is_software_node(cc->gpio.fwnode)) {
+		software_node_unregister(&bcma_gpio_swnode);
+		cc->gpio.fwnode = NULL;
+	}
 	return 0;
 }
diff --git a/include/linux/bcma/bcma.h b/include/linux/bcma/bcma.h
index f02cb3909375..17fc50190014 100644
--- a/include/linux/bcma/bcma.h
+++ b/include/linux/bcma/bcma.h
@@ -486,4 +486,6 @@ extern u32 bcma_core_dma_translation(struct bcma_device *core);
 
 extern unsigned int bcma_core_irq(struct bcma_device *core, int num);
 
+extern const struct software_node bcma_gpio_swnode;
+
 #endif /* LINUX_BCMA_H_ */

-- 
2.55.0.795.g602f6c329a-goog