gpio: sim: convert to use dev-sync-probe utilities

Update gpio-sim to use the new dev-sync-probe helper functions for
synchronized platform device creation, reducing code duplication.

No functional change.

Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Link: https://lore.kernel.org/r/20250221133501.2203897-3-koichiro.den@canonical.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

2 files changed, 13 insertions, 72 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index d6ac1a01c636..5b167c413422 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1910,6 +1910,7 @@ config GPIO_SIM
 	tristate "GPIO Simulator Module"
 	select IRQ_SIM
 	select CONFIGFS_FS
+	select DEV_SYNC_PROBE
 	help
 	  This enables the GPIO simulator - a configfs-based GPIO testing
 	  driver.
diff --git a/drivers/gpio/gpio-sim.c b/drivers/gpio/gpio-sim.c
index b6c230fab840..758933fbd85b 100644
--- a/drivers/gpio/gpio-sim.c
+++ b/drivers/gpio/gpio-sim.c
@@ -10,7 +10,6 @@
 #include <linux/array_size.h>
 #include <linux/bitmap.h>
 #include <linux/cleanup.h>
-#include <linux/completion.h>
 #include <linux/configfs.h>
 #include <linux/device.h>
 #include <linux/err.h>
@@ -37,6 +36,8 @@
 #include <linux/sysfs.h>
 #include <linux/types.h>
 
+#include "dev-sync-probe.h"
+
 #define GPIO_SIM_NGPIO_MAX	1024
 #define GPIO_SIM_PROP_MAX	4 /* Max 3 properties + sentinel. */
 #define GPIO_SIM_NUM_ATTRS	3 /* value, pull and sentinel */
@@ -541,14 +542,9 @@ static struct platform_driver gpio_sim_driver = {
 };
 
 struct gpio_sim_device {
+	struct dev_sync_probe_data probe_data;
 	struct config_group group;
 
-	/*
-	 * If pdev is NULL, the device is 'pending' (waiting for configuration).
-	 * Once the pointer is assigned, the device has been created and the
-	 * item is 'live'.
-	 */
-	struct platform_device *pdev;
 	int id;
 
 	/*
@@ -562,46 +558,11 @@ struct gpio_sim_device {
 	 */
 	struct mutex lock;
 
-	/*
-	 * This is used to synchronously wait for the driver's probe to complete
-	 * and notify the user-space about any errors.
-	 */
-	struct notifier_block bus_notifier;
-	struct completion probe_completion;
-	bool driver_bound;
-
 	struct gpiod_hog *hogs;
 
 	struct list_head bank_list;
 };
 
-/* This is called with dev->lock already taken. */
-static int gpio_sim_bus_notifier_call(struct notifier_block *nb,
-				      unsigned long action, void *data)
-{
-	struct gpio_sim_device *simdev = container_of(nb,
-						      struct gpio_sim_device,
-						      bus_notifier);
-	struct device *dev = data;
-	char devname[32];
-
-	snprintf(devname, sizeof(devname), "gpio-sim.%u", simdev->id);
-
-	if (!device_match_name(dev, devname))
-		return NOTIFY_DONE;
-
-	if (action == BUS_NOTIFY_BOUND_DRIVER)
-		simdev->driver_bound = true;
-	else if (action == BUS_NOTIFY_DRIVER_NOT_BOUND)
-		simdev->driver_bound = false;
-	else
-		return NOTIFY_DONE;
-
-	complete(&simdev->probe_completion);
-
-	return NOTIFY_OK;
-}
-
 static struct gpio_sim_device *to_gpio_sim_device(struct config_item *item)
 {
 	struct config_group *group = to_config_group(item);
@@ -708,7 +669,7 @@ static bool gpio_sim_device_is_live(struct gpio_sim_device *dev)
 {
 	lockdep_assert_held(&dev->lock);
 
-	return !!dev->pdev;
+	return !!dev->probe_data.pdev;
 }
 
 static char *gpio_sim_strdup_trimmed(const char *str, size_t count)
@@ -730,7 +691,7 @@ static ssize_t gpio_sim_device_config_dev_name_show(struct config_item *item,
 
 	guard(mutex)(&dev->lock);
 
-	pdev = dev->pdev;
+	pdev = dev->probe_data.pdev;
 	if (pdev)
 		return sprintf(page, "%s\n", dev_name(&pdev->dev));
 
@@ -939,7 +900,6 @@ static int gpio_sim_device_activate(struct gpio_sim_device *dev)
 {
 	struct platform_device_info pdevinfo;
 	struct fwnode_handle *swnode;
-	struct platform_device *pdev;
 	struct gpio_sim_bank *bank;
 	int ret;
 
@@ -981,31 +941,13 @@ static int gpio_sim_device_activate(struct gpio_sim_device *dev)
 	pdevinfo.fwnode = swnode;
 	pdevinfo.id = dev->id;
 
-	reinit_completion(&dev->probe_completion);
-	dev->driver_bound = false;
-	bus_register_notifier(&platform_bus_type, &dev->bus_notifier);
-
-	pdev = platform_device_register_full(&pdevinfo);
-	if (IS_ERR(pdev)) {
-		bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier);
-		gpio_sim_remove_hogs(dev);
-		gpio_sim_remove_swnode_recursive(swnode);
-		return PTR_ERR(pdev);
-	}
-
-	wait_for_completion(&dev->probe_completion);
-	bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier);
-
-	if (!dev->driver_bound) {
-		/* Probe failed, check kernel log. */
-		platform_device_unregister(pdev);
+	ret = dev_sync_probe_register(&dev->probe_data, &pdevinfo);
+	if (ret) {
 		gpio_sim_remove_hogs(dev);
 		gpio_sim_remove_swnode_recursive(swnode);
-		return -ENXIO;
+		return ret;
 	}
 
-	dev->pdev = pdev;
-
 	return 0;
 }
 
@@ -1015,11 +957,10 @@ static void gpio_sim_device_deactivate(struct gpio_sim_device *dev)
 
 	lockdep_assert_held(&dev->lock);
 
-	swnode = dev_fwnode(&dev->pdev->dev);
-	platform_device_unregister(dev->pdev);
+	swnode = dev_fwnode(&dev->probe_data.pdev->dev);
+	dev_sync_probe_unregister(&dev->probe_data);
 	gpio_sim_remove_hogs(dev);
 	gpio_sim_remove_swnode_recursive(swnode);
-	dev->pdev = NULL;
 }
 
 static void
@@ -1120,7 +1061,7 @@ static ssize_t gpio_sim_bank_config_chip_name_show(struct config_item *item,
 	guard(mutex)(&dev->lock);
 
 	if (gpio_sim_device_is_live(dev))
-		return device_for_each_child(&dev->pdev->dev, &ctx,
+		return device_for_each_child(&dev->probe_data.pdev->dev, &ctx,
 					     gpio_sim_emit_chip_name);
 
 	return sprintf(page, "none\n");
@@ -1561,8 +1502,7 @@ gpio_sim_config_make_device_group(struct config_group *group, const char *name)
 	mutex_init(&dev->lock);
 	INIT_LIST_HEAD(&dev->bank_list);
 
-	dev->bus_notifier.notifier_call = gpio_sim_bus_notifier_call;
-	init_completion(&dev->probe_completion);
+	dev_sync_probe_init(&dev->probe_data);
 
 	return &no_free_ptr(dev)->group;
 }