1 files changed, 67 insertions, 0 deletions

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 43aeb07343ec..547adc149b62 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -71,6 +71,9 @@ static DEFINE_MUTEX(gpio_lookup_lock);
 static LIST_HEAD(gpio_lookup_list);
 LIST_HEAD(gpio_devices);
 
+static DEFINE_MUTEX(gpio_machine_hogs_mutex);
+static LIST_HEAD(gpio_machine_hogs);
+
 static void gpiochip_free_hogs(struct gpio_chip *chip);
 static int gpiochip_add_irqchip(struct gpio_chip *gpiochip,
 				struct lock_class_key *lock_key,
@@ -1171,6 +1174,41 @@ err_remove_device:
 	return status;
 }
 
+static void gpiochip_machine_hog(struct gpio_chip *chip, struct gpiod_hog *hog)
+{
+	struct gpio_desc *desc;
+	int rv;
+
+	desc = gpiochip_get_desc(chip, hog->chip_hwnum);
+	if (IS_ERR(desc)) {
+		pr_err("%s: unable to get GPIO desc: %ld\n",
+		       __func__, PTR_ERR(desc));
+		return;
+	}
+
+	if (desc->flags & FLAG_IS_HOGGED)
+		return;
+
+	rv = gpiod_hog(desc, hog->line_name, hog->lflags, hog->dflags);
+	if (rv)
+		pr_err("%s: unable to hog GPIO line (%s:%u): %d\n",
+		       __func__, chip->label, hog->chip_hwnum, rv);
+}
+
+static void machine_gpiochip_add(struct gpio_chip *chip)
+{
+	struct gpiod_hog *hog;
+
+	mutex_lock(&gpio_machine_hogs_mutex);
+
+	list_for_each_entry(hog, &gpio_machine_hogs, list) {
+		if (!strcmp(chip->label, hog->chip_label))
+			gpiochip_machine_hog(chip, hog);
+	}
+
+	mutex_unlock(&gpio_machine_hogs_mutex);
+}
+
 static void gpiochip_setup_devs(void)
 {
 	struct gpio_device *gdev;
@@ -1326,6 +1364,8 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
 
 	acpi_gpiochip_add(chip);
 
+	machine_gpiochip_add(chip);
+
 	/*
 	 * By first adding the chardev, and then adding the device,
 	 * we get a device node entry in sysfs under
@@ -3462,6 +3502,33 @@ void gpiod_remove_lookup_table(struct gpiod_lookup_table *table)
 }
 EXPORT_SYMBOL_GPL(gpiod_remove_lookup_table);
 
+/**
+ * gpiod_add_hogs() - register a set of GPIO hogs from machine code
+ * @hogs: table of gpio hog entries with a zeroed sentinel at the end
+ */
+void gpiod_add_hogs(struct gpiod_hog *hogs)
+{
+	struct gpio_chip *chip;
+	struct gpiod_hog *hog;
+
+	mutex_lock(&gpio_machine_hogs_mutex);
+
+	for (hog = &hogs[0]; hog->chip_label; hog++) {
+		list_add_tail(&hog->list, &gpio_machine_hogs);
+
+		/*
+		 * The chip may have been registered earlier, so check if it
+		 * exists and, if so, try to hog the line now.
+		 */
+		chip = find_chip_by_name(hog->chip_label);
+		if (chip)
+			gpiochip_machine_hog(chip, hog);
+	}
+
+	mutex_unlock(&gpio_machine_hogs_mutex);
+}
+EXPORT_SYMBOL_GPL(gpiod_add_hogs);
+
 static struct gpiod_lookup_table *gpiod_find_lookup_table(struct device *dev)
 {
 	const char *dev_id = dev ? dev_name(dev) : NULL;