1 files changed, 104 insertions, 21 deletions

diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
index 650de4da0853..d1e6598ea3bc 100644
--- a/drivers/gpu/drm/drm_panel.c
+++ b/drivers/gpu/drm/drm_panel.c
@@ -23,6 +23,7 @@
 
 #include <linux/backlight.h>
 #include <linux/err.h>
+#include <linux/export.h>
 #include <linux/module.h>
 #include <linux/of.h>
 
@@ -133,6 +134,9 @@ void drm_panel_prepare(struct drm_panel *panel)
 	panel->prepared = true;
 
 	list_for_each_entry(follower, &panel->followers, list) {
+		if (!follower->funcs->panel_prepared)
+			continue;
+
 		ret = follower->funcs->panel_prepared(follower);
 		if (ret < 0)
 			dev_info(panel->dev, "%ps failed: %d\n",
@@ -178,6 +182,9 @@ void drm_panel_unprepare(struct drm_panel *panel)
 	mutex_lock(&panel->follower_lock);
 
 	list_for_each_entry(follower, &panel->followers, list) {
+		if (!follower->funcs->panel_unpreparing)
+			continue;
+
 		ret = follower->funcs->panel_unpreparing(follower);
 		if (ret < 0)
 			dev_info(panel->dev, "%ps failed: %d\n",
@@ -208,6 +215,7 @@ EXPORT_SYMBOL(drm_panel_unprepare);
  */
 void drm_panel_enable(struct drm_panel *panel)
 {
+	struct drm_panel_follower *follower;
 	int ret;
 
 	if (!panel)
@@ -218,10 +226,12 @@ void drm_panel_enable(struct drm_panel *panel)
 		return;
 	}
 
+	mutex_lock(&panel->follower_lock);
+
 	if (panel->funcs && panel->funcs->enable) {
 		ret = panel->funcs->enable(panel);
 		if (ret < 0)
-			return;
+			goto exit;
 	}
 	panel->enabled = true;
 
@@ -229,6 +239,19 @@ void drm_panel_enable(struct drm_panel *panel)
 	if (ret < 0)
 		DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n",
 			     ret);
+
+	list_for_each_entry(follower, &panel->followers, list) {
+		if (!follower->funcs->panel_enabled)
+			continue;
+
+		ret = follower->funcs->panel_enabled(follower);
+		if (ret < 0)
+			dev_info(panel->dev, "%ps failed: %d\n",
+				 follower->funcs->panel_enabled, ret);
+	}
+
+exit:
+	mutex_unlock(&panel->follower_lock);
 }
 EXPORT_SYMBOL(drm_panel_enable);
 
@@ -242,6 +265,7 @@ EXPORT_SYMBOL(drm_panel_enable);
  */
 void drm_panel_disable(struct drm_panel *panel)
 {
+	struct drm_panel_follower *follower;
 	int ret;
 
 	if (!panel)
@@ -261,6 +285,18 @@ void drm_panel_disable(struct drm_panel *panel)
 		return;
 	}
 
+	mutex_lock(&panel->follower_lock);
+
+	list_for_each_entry(follower, &panel->followers, list) {
+		if (!follower->funcs->panel_disabling)
+			continue;
+
+		ret = follower->funcs->panel_disabling(follower);
+		if (ret < 0)
+			dev_info(panel->dev, "%ps failed: %d\n",
+				 follower->funcs->panel_disabling, ret);
+	}
+
 	ret = backlight_disable(panel->backlight);
 	if (ret < 0)
 		DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n",
@@ -269,9 +305,12 @@ void drm_panel_disable(struct drm_panel *panel)
 	if (panel->funcs && panel->funcs->disable) {
 		ret = panel->funcs->disable(panel);
 		if (ret < 0)
-			return;
+			goto exit;
 	}
 	panel->enabled = false;
+
+exit:
+	mutex_unlock(&panel->follower_lock);
 }
 EXPORT_SYMBOL(drm_panel_disable);
 
@@ -473,13 +512,51 @@ int of_drm_get_panel_orientation(const struct device_node *np,
 EXPORT_SYMBOL(of_drm_get_panel_orientation);
 #endif
 
+/* Find panel by fwnode. This should be identical to of_drm_find_panel(). */
+static struct drm_panel *find_panel_by_fwnode(const struct fwnode_handle *fwnode)
+{
+	struct drm_panel *panel;
+
+	if (!fwnode_device_is_available(fwnode))
+		return ERR_PTR(-ENODEV);
+
+	mutex_lock(&panel_lock);
+
+	list_for_each_entry(panel, &panel_list, list) {
+		if (dev_fwnode(panel->dev) == fwnode) {
+			mutex_unlock(&panel_lock);
+			return panel;
+		}
+	}
+
+	mutex_unlock(&panel_lock);
+
+	return ERR_PTR(-EPROBE_DEFER);
+}
+
+/* Find panel by follower device */
+static struct drm_panel *find_panel_by_dev(struct device *follower_dev)
+{
+	struct fwnode_handle *fwnode;
+	struct drm_panel *panel;
+
+	fwnode = fwnode_find_reference(dev_fwnode(follower_dev), "panel", 0);
+	if (IS_ERR(fwnode))
+		return ERR_PTR(-ENODEV);
+
+	panel = find_panel_by_fwnode(fwnode);
+	fwnode_handle_put(fwnode);
+
+	return panel;
+}
+
 /**
  * drm_is_panel_follower() - Check if the device is a panel follower
  * @dev: The 'struct device' to check
  *
  * This checks to see if a device needs to be power sequenced together with
  * a panel using the panel follower API.
- * At the moment panels can only be followed on device tree enabled systems.
+ *
  * The "panel" property of the follower points to the panel to be followed.
  *
  * Return: true if we should be power sequenced with a panel; false otherwise.
@@ -491,7 +568,7 @@ bool drm_is_panel_follower(struct device *dev)
 	 * don't bother trying to parse it here. We just need to know if the
 	 * property is there.
 	 */
-	return of_property_present(dev->of_node, "panel");
+	return device_property_present(dev, "panel");
 }
 EXPORT_SYMBOL(drm_is_panel_follower);
 
@@ -500,15 +577,14 @@ EXPORT_SYMBOL(drm_is_panel_follower);
  * @follower_dev: The 'struct device' for the follower.
  * @follower:     The panel follower descriptor for the follower.
  *
- * A panel follower is called right after preparing the panel and right before
- * unpreparing the panel. It's primary intention is to power on an associated
- * touchscreen, though it could be used for any similar devices. Multiple
- * devices are allowed the follow the same panel.
+ * A panel follower is called right after preparing/enabling the panel and right
+ * before unpreparing/disabling the panel. It's primary intention is to power on
+ * an associated touchscreen, though it could be used for any similar devices.
+ * Multiple devices are allowed the follow the same panel.
  *
- * If a follower is added to a panel that's already been turned on, the
- * follower's prepare callback is called right away.
+ * If a follower is added to a panel that's already been prepared/enabled, the
+ * follower's prepared/enabled callback is called right away.
  *
- * At the moment panels can only be followed on device tree enabled systems.
  * The "panel" property of the follower points to the panel to be followed.
  *
  * Return: 0 or an error code. Note that -ENODEV means that we detected that
@@ -518,16 +594,10 @@ EXPORT_SYMBOL(drm_is_panel_follower);
 int drm_panel_add_follower(struct device *follower_dev,
 			   struct drm_panel_follower *follower)
 {
-	struct device_node *panel_np;
 	struct drm_panel *panel;
 	int ret;
 
-	panel_np = of_parse_phandle(follower_dev->of_node, "panel", 0);
-	if (!panel_np)
-		return -ENODEV;
-
-	panel = of_drm_find_panel(panel_np);
-	of_node_put(panel_np);
+	panel = find_panel_by_dev(follower_dev);
 	if (IS_ERR(panel))
 		return PTR_ERR(panel);
 
@@ -537,12 +607,18 @@ int drm_panel_add_follower(struct device *follower_dev,
 	mutex_lock(&panel->follower_lock);
 
 	list_add_tail(&follower->list, &panel->followers);
-	if (panel->prepared) {
+	if (panel->prepared && follower->funcs->panel_prepared) {
 		ret = follower->funcs->panel_prepared(follower);
 		if (ret < 0)
 			dev_info(panel->dev, "%ps failed: %d\n",
 				 follower->funcs->panel_prepared, ret);
 	}
+	if (panel->enabled && follower->funcs->panel_enabled) {
+		ret = follower->funcs->panel_enabled(follower);
+		if (ret < 0)
+			dev_info(panel->dev, "%ps failed: %d\n",
+				 follower->funcs->panel_enabled, ret);
+	}
 
 	mutex_unlock(&panel->follower_lock);
 
@@ -555,7 +631,8 @@ EXPORT_SYMBOL(drm_panel_add_follower);
  * @follower:     The panel follower descriptor for the follower.
  *
  * Undo drm_panel_add_follower(). This includes calling the follower's
- * unprepare function if we're removed from a panel that's currently prepared.
+ * unpreparing/disabling function if we're removed from a panel that's currently
+ * prepared/enabled.
  *
  * Return: 0 or an error code.
  */
@@ -566,7 +643,13 @@ void drm_panel_remove_follower(struct drm_panel_follower *follower)
 
 	mutex_lock(&panel->follower_lock);
 
-	if (panel->prepared) {
+	if (panel->enabled && follower->funcs->panel_disabling) {
+		ret = follower->funcs->panel_disabling(follower);
+		if (ret < 0)
+			dev_info(panel->dev, "%ps failed: %d\n",
+				 follower->funcs->panel_disabling, ret);
+	}
+	if (panel->prepared && follower->funcs->panel_unpreparing) {
 		ret = follower->funcs->panel_unpreparing(follower);
 		if (ret < 0)
 			dev_info(panel->dev, "%ps failed: %d\n",