Convert gpio-sim to using software nodes for setting up simulated hogs
instead of legacy machine hogs.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
---
 drivers/gpio/gpio-sim.c | 162 +++++++++++++++++-------------------------------
 1 file changed, 56 insertions(+), 106 deletions(-)

diff --git a/drivers/gpio/gpio-sim.c b/drivers/gpio/gpio-sim.c
index 13b87c8e6d0caf62ce311dad409a9b4d3f091caa..51bcbdd91b4b027b7a340971a11cce5280ca1295 100644
--- a/drivers/gpio/gpio-sim.c
+++ b/drivers/gpio/gpio-sim.c
@@ -40,6 +40,7 @@
 
 #define GPIO_SIM_NGPIO_MAX	1024
 #define GPIO_SIM_PROP_MAX	5 /* Max 4 properties + sentinel. */
+#define GPIO_SIM_HOG_PROP_MAX	5
 #define GPIO_SIM_NUM_ATTRS	3 /* value, pull and sentinel */
 
 static DEFINE_IDA(gpio_sim_ida);
@@ -561,8 +562,6 @@ struct gpio_sim_device {
 	 */
 	struct mutex lock;
 
-	struct gpiod_hog *hogs;
-
 	struct list_head bank_list;
 };
 
@@ -774,102 +773,6 @@ static void gpio_sim_set_reserved_ranges(struct gpio_sim_bank *bank,
 	}
 }
 
-static void gpio_sim_remove_hogs(struct gpio_sim_device *dev)
-{
-	struct gpiod_hog *hog;
-
-	if (!dev->hogs)
-		return;
-
-	gpiod_remove_hogs(dev->hogs);
-
-	for (hog = dev->hogs; hog->chip_label; hog++) {
-		kfree(hog->chip_label);
-		kfree(hog->line_name);
-	}
-
-	kfree(dev->hogs);
-	dev->hogs = NULL;
-}
-
-static int gpio_sim_add_hogs(struct gpio_sim_device *dev)
-{
-	unsigned int num_hogs = 0, idx = 0;
-	struct gpio_sim_bank *bank;
-	struct gpio_sim_line *line;
-	struct gpiod_hog *hog;
-
-	list_for_each_entry(bank, &dev->bank_list, siblings) {
-		list_for_each_entry(line, &bank->line_list, siblings) {
-			if (line->offset >= bank->num_lines)
-				continue;
-
-			if (line->hog)
-				num_hogs++;
-		}
-	}
-
-	if (!num_hogs)
-		return 0;
-
-	/* Allocate one more for the sentinel. */
-	dev->hogs = kzalloc_objs(*dev->hogs, num_hogs + 1);
-	if (!dev->hogs)
-		return -ENOMEM;
-
-	list_for_each_entry(bank, &dev->bank_list, siblings) {
-		list_for_each_entry(line, &bank->line_list, siblings) {
-			if (line->offset >= bank->num_lines)
-				continue;
-
-			if (!line->hog)
-				continue;
-
-			hog = &dev->hogs[idx++];
-
-			/*
-			 * We need to make this string manually because at this
-			 * point the device doesn't exist yet and so dev_name()
-			 * is not available.
-			 */
-			if (gpio_sim_bank_has_label(bank))
-				hog->chip_label = kstrdup(bank->label,
-							  GFP_KERNEL);
-			else
-				hog->chip_label = kasprintf(GFP_KERNEL,
-							"gpio-sim.%u:%pfwP",
-							dev->id,
-							bank->swnode);
-			if (!hog->chip_label) {
-				gpio_sim_remove_hogs(dev);
-				return -ENOMEM;
-			}
-
-			/*
-			 * We need to duplicate this because the hog config
-			 * item can be removed at any time (and we can't block
-			 * it) and gpiolib doesn't make a deep copy of the hog
-			 * data.
-			 */
-			if (line->hog->name) {
-				hog->line_name = kstrdup(line->hog->name,
-							 GFP_KERNEL);
-				if (!hog->line_name) {
-					gpio_sim_remove_hogs(dev);
-					return -ENOMEM;
-				}
-			}
-
-			hog->chip_hwnum = line->offset;
-			hog->dflags = line->hog->dir;
-		}
-	}
-
-	gpiod_add_hogs(dev->hogs);
-
-	return 0;
-}
-
 static struct fwnode_handle *
 gpio_sim_make_bank_swnode(struct gpio_sim_bank *bank,
 			  struct fwnode_handle *parent)
@@ -917,12 +820,61 @@ gpio_sim_make_bank_swnode(struct gpio_sim_bank *bank,
 	return fwnode_create_software_node(properties, parent);
 }
 
+static int gpio_sim_bank_add_hogs(struct gpio_sim_bank *bank)
+{
+	struct property_entry properties[GPIO_SIM_HOG_PROP_MAX];
+	struct fwnode_handle *swnode;
+	struct gpio_sim_line *line;
+	struct gpio_sim_hog *hog;
+	unsigned int idx;
+	u32 gpios[2];
+
+	list_for_each_entry(line, &bank->line_list, siblings) {
+		if (!line->hog)
+			continue;
+
+		hog = line->hog;
+
+		gpios[0] = line->offset;
+		gpios[1] = 0;
+
+		memset(properties, 0, sizeof(properties));
+
+		idx = 0;
+		properties[idx++] = PROPERTY_ENTRY_BOOL("gpio-hog");
+		properties[idx++] = PROPERTY_ENTRY_U32_ARRAY("gpios", gpios);
+		properties[idx++] = PROPERTY_ENTRY_STRING("line-name", hog->name);
+
+		switch (hog->dir) {
+		case GPIOD_IN:
+			properties[idx++] = PROPERTY_ENTRY_BOOL("input");
+			break;
+		case GPIOD_OUT_HIGH:
+			properties[idx++] = PROPERTY_ENTRY_BOOL("output-high");
+			break;
+		case GPIOD_OUT_LOW:
+			properties[idx++] = PROPERTY_ENTRY_BOOL("output-low");
+			break;
+		default:
+			/* Would have been validated at configfs store. */
+			WARN(1, "Unexpected hog direction value: %d", hog->dir);
+			return -EINVAL;
+		}
+
+		swnode = fwnode_create_software_node(properties, bank->swnode);
+		if (IS_ERR(swnode))
+			return PTR_ERR(swnode);
+	}
+
+	return 0;
+}
+
 static void gpio_sim_remove_swnode_recursive(struct fwnode_handle *swnode)
 {
 	struct fwnode_handle *child;
 
 	fwnode_for_each_child_node(swnode, child)
-		fwnode_remove_software_node(child);
+		gpio_sim_remove_swnode_recursive(child);
 
 	fwnode_remove_software_node(swnode);
 }
@@ -977,12 +929,12 @@ static int gpio_sim_device_activate(struct gpio_sim_device *dev)
 			gpio_sim_remove_swnode_recursive(swnode);
 			return ret;
 		}
-	}
 
-	ret = gpio_sim_add_hogs(dev);
-	if (ret) {
-		gpio_sim_remove_swnode_recursive(swnode);
-		return ret;
+		ret = gpio_sim_bank_add_hogs(bank);
+		if (ret) {
+			gpio_sim_remove_swnode_recursive(swnode);
+			return ret;
+		}
 	}
 
 	pdevinfo.name = "gpio-sim";
@@ -991,7 +943,6 @@ static int gpio_sim_device_activate(struct gpio_sim_device *dev)
 
 	ret = dev_sync_probe_register(&dev->probe_data, &pdevinfo);
 	if (ret) {
-		gpio_sim_remove_hogs(dev);
 		gpio_sim_remove_swnode_recursive(swnode);
 		return ret;
 	}
@@ -1007,7 +958,6 @@ static void gpio_sim_device_deactivate(struct gpio_sim_device *dev)
 
 	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);
 }
 

-- 
2.47.3

On Thu, Mar 5, 2026 at 10:51 AM Bartosz Golaszewski
<bartosz.golaszewski@oss.qualcomm.com> wrote:

> Convert gpio-sim to using software nodes for setting up simulated hogs
> instead of legacy machine hogs.
>
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

Reviewed-by: Linus Walleij <linusw@kernel.org>

Yours,
Linus Walleij