3 files changed, 54 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index e4620e14457f..07e571a1a377 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -925,3 +925,46 @@ int acpi_gpio_count(struct device *dev, const char *con_id)
 	}
 	return count;
 }
+
+struct acpi_crs_lookup {
+	struct list_head node;
+	struct acpi_device *adev;
+	const char *con_id;
+};
+
+static DEFINE_MUTEX(acpi_crs_lookup_lock);
+static LIST_HEAD(acpi_crs_lookup_list);
+
+bool acpi_can_fallback_to_crs(struct acpi_device *adev, const char *con_id)
+{
+	struct acpi_crs_lookup *l, *lookup = NULL;
+
+	/* Never allow fallback if the device has properties */
+	if (adev->data.properties || adev->driver_gpios)
+		return false;
+
+	mutex_lock(&acpi_crs_lookup_lock);
+
+	list_for_each_entry(l, &acpi_crs_lookup_list, node) {
+		if (l->adev == adev) {
+			lookup = l;
+			break;
+		}
+	}
+
+	if (!lookup) {
+		lookup = kmalloc(sizeof(*lookup), GFP_KERNEL);
+		if (lookup) {
+			lookup->adev = adev;
+			lookup->con_id = con_id;
+			list_add_tail(&lookup->node, &acpi_crs_lookup_list);
+		}
+	}
+
+	mutex_unlock(&acpi_crs_lookup_lock);
+
+	return lookup &&
+		((!lookup->con_id && !con_id) ||
+		 (lookup->con_id && con_id &&
+		  strcmp(lookup->con_id, con_id) == 0));
+}
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 8b35457013da..dfe09c06df49 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1869,6 +1869,9 @@ static struct gpio_desc *acpi_find_gpio(struct device *dev, const char *con_id,
 
 	/* Then from plain _CRS GPIOs */
 	if (IS_ERR(desc)) {
+		if (!acpi_can_fallback_to_crs(adev, con_id))
+			return ERR_PTR(-ENOENT);
+
 		desc = acpi_get_gpiod_by_index(adev, NULL, idx, &info);
 		if (IS_ERR(desc))
 			return desc;
diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h
index 98ab08c0aa2d..2b87cbd68478 100644
--- a/drivers/gpio/gpiolib.h
+++ b/drivers/gpio/gpiolib.h
@@ -47,6 +47,8 @@ struct gpio_desc *acpi_node_get_gpiod(struct fwnode_handle *fwnode,
 				      struct acpi_gpio_info *info);
 
 int acpi_gpio_count(struct device *dev, const char *con_id);
+
+bool acpi_can_fallback_to_crs(struct acpi_device *adev, const char *con_id);
 #else
 static inline void acpi_gpiochip_add(struct gpio_chip *chip) { }
 static inline void acpi_gpiochip_remove(struct gpio_chip *chip) { }
@@ -73,6 +75,12 @@ static inline int acpi_gpio_count(struct device *dev, const char *con_id)
 {
 	return -ENODEV;
 }
+
+static inline bool acpi_can_fallback_to_crs(struct acpi_device *adev,
+					    const char *con_id)
+{
+	return false;
+}
 #endif
 
 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,