[RFC 10/15] drm/exynos/dsi: simplify hotplug code

[Andrzej Hajda]

Exynos DSI driver uses DSI bus attach/detach callbacks to implement
panel hotplug mechanism. The patch moves panel attachment code
from .detect callback to DSI bus callbacks. It makes the code
simpler and more straightforward.
The patch removes also redundant and lock unprotected dpms_off call
from unbind code.

Signed-off-by: Andrzej Hajda <a.hajda at samsung.com>
---
 drivers/gpu/drm/exynos/exynos_drm_dsi.c | 61 ++++++++++++++++++++-------------
 1 file changed, 38 insertions(+), 23 deletions(-)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
index 05fe93d..8201d79 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
@@ -271,7 +271,6 @@ struct exynos_dsi {
 	struct exynos_drm_display display;
 	struct mipi_dsi_host dsi_host;
 	struct drm_connector connector;
-	struct device_node *panel_node;
 	struct drm_panel *panel;
 	struct device *dev;
 
@@ -1154,10 +1153,11 @@ static int exynos_dsi_init(struct exynos_dsi *dsi)
 
 static int exynos_dsi_register_te_irq(struct exynos_dsi *dsi)
 {
+	struct device_node *panel_node = dsi->panel->dev->of_node;
 	int ret;
 	int te_gpio_irq;
 
-	dsi->te_gpio = of_get_named_gpio(dsi->panel_node, "te-gpios", 0);
+	dsi->te_gpio = of_get_named_gpio(panel_node, "te-gpios", 0);
 	if (!gpio_is_valid(dsi->te_gpio)) {
 		dev_err(dsi->dev, "no te-gpios specified\n");
 		ret = dsi->te_gpio;
@@ -1198,11 +1198,25 @@ static int exynos_dsi_host_attach(struct mipi_dsi_host *host,
 				  struct mipi_dsi_device *device)
 {
 	struct exynos_dsi *dsi = host_to_dsi(host);
+	struct drm_device *drm_dev = dsi->connector.dev;
+	bool changed = false;
 
 	dsi->lanes = device->lanes;
 	dsi->format = device->format;
 	dsi->mode_flags = device->mode_flags;
-	dsi->panel_node = device->dev.of_node;
+
+	mutex_lock(&drm_dev->mode_config.mutex);
+
+	dsi->panel = of_drm_find_panel(device->dev.of_node);
+	if (dsi->panel) {
+		drm_panel_attach(dsi->panel, &dsi->connector);
+		if (drm_dev->mode_config.poll_enabled) {
+			dsi->connector.status = connector_status_connected;
+			changed = true;
+		}
+	}
+
+	mutex_unlock(&drm_dev->mode_config.mutex);
 
 	/*
 	 * This is a temporary solution and should be made by more generic way.
@@ -1217,8 +1231,8 @@ static int exynos_dsi_host_attach(struct mipi_dsi_host *host,
 			return ret;
 	}
 
-	if (dsi->connector.dev)
-		drm_helper_hpd_irq_event(dsi->connector.dev);
+	if (changed)
+		drm_kms_helper_hotplug_event(drm_dev);
 
 	return 0;
 }
@@ -1227,13 +1241,29 @@ static int exynos_dsi_host_detach(struct mipi_dsi_host *host,
 				  struct mipi_dsi_device *device)
 {
 	struct exynos_dsi *dsi = host_to_dsi(host);
+	struct drm_device *drm_dev = dsi->connector.dev;
+	struct exynos_drm_display *display = dev_get_drvdata(dsi->dev);
+	bool changed = false;
 
 	exynos_dsi_unregister_te_irq(dsi);
 
-	dsi->panel_node = NULL;
+	mutex_lock(&drm_dev->mode_config.mutex);
+
+	display->ops->dpms(display, DRM_MODE_DPMS_OFF);
+
+	if (dsi->panel) {
+		drm_panel_detach(dsi->panel);
+		dsi->panel = NULL;
+		if (drm_dev->mode_config.poll_enabled) {
+			dsi->connector.status = connector_status_disconnected;
+			changed = true;
+		}
+	}
+
+	mutex_unlock(&drm_dev->mode_config.mutex);
 
-	if (dsi->connector.dev)
-		drm_helper_hpd_irq_event(dsi->connector.dev);
+	if (changed)
+		drm_kms_helper_hotplug_event(drm_dev);
 
 	return 0;
 }
@@ -1430,19 +1460,6 @@ exynos_dsi_detect(struct drm_connector *connector, bool force)
 {
 	struct exynos_dsi *dsi = connector_to_dsi(connector);
 
-	if (!dsi->panel) {
-		dsi->panel = of_drm_find_panel(dsi->panel_node);
-		if (dsi->panel)
-			drm_panel_attach(dsi->panel, &dsi->connector);
-	} else if (!dsi->panel_node) {
-		struct exynos_drm_display *display;
-
-		display = platform_get_drvdata(to_platform_device(dsi->dev));
-		exynos_dsi_dpms(display, DRM_MODE_DPMS_OFF);
-		drm_panel_detach(dsi->panel);
-		dsi->panel = NULL;
-	}
-
 	if (dsi->panel)
 		return connector_status_connected;
 
@@ -1665,8 +1682,6 @@ static void exynos_dsi_unbind(struct device *dev, struct device *master,
 	struct exynos_drm_display *display = dev_get_drvdata(dev);
 	struct exynos_dsi *dsi = display_to_dsi(display);
 
-	exynos_dsi_dpms(display, DRM_MODE_DPMS_OFF);
-
 	mipi_dsi_host_unregister(&dsi->dsi_host);
 }
 
-- 
1.9.1