drm/stm: ltdc: check number of endpoints

Number of endpoints could exceed the fix value MAX_ENDPOINTS(2).
Instead of increase simply this value, the number of endpoint
could be read from device tree. Load sequence has been a little
rework to take care of several panel or bridge which can be
connected/disconnected or enable/disable.

Signed-off-by: Yannick Fertre <yannick.fertre@st.com>
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1582877258-1112-1-git-send-email-yannick.fertre@st.com

diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
index df585fe..f894968 100644 (file)
--- a/drivers/gpu/drm/stm/ltdc.c
+++ b/drivers/gpu/drm/stm/ltdc.c
@@ -42,8 +42,6 @@
 
 #define MAX_IRQ 4
 
-#define MAX_ENDPOINTS 2
-
 #define HWVER_10200 0x010200
 #define HWVER_10300 0x010300
 #define HWVER_20101 0x020101
@@ -1201,36 +1199,20 @@ int ltdc_load(struct drm_device *ddev)
        struct ltdc_device *ldev = ddev->dev_private;
        struct device *dev = ddev->dev;
        struct device_node *np = dev->of_node;
-       struct drm_bridge *bridge[MAX_ENDPOINTS] = {NULL};
-       struct drm_panel *panel[MAX_ENDPOINTS] = {NULL};
+       struct drm_bridge *bridge;
+       struct drm_panel *panel;
        struct drm_crtc *crtc;
        struct reset_control *rstc;
        struct resource *res;
-       int irq, ret, i, endpoint_not_ready = -ENODEV;
+       int irq, i, nb_endpoints;
+       int ret = -ENODEV;
 
        DRM_DEBUG_DRIVER("\n");
 
-       /* Get endpoints if any */
-       for (i = 0; i < MAX_ENDPOINTS; i++) {
-               ret = drm_of_find_panel_or_bridge(np, 0, i, &panel[i],
-                                                 &bridge[i]);
-
-               /*
-                * If at least one endpoint is -EPROBE_DEFER, defer probing,
-                * else if at least one endpoint is ready, continue probing.
-                */
-               if (ret == -EPROBE_DEFER)
-                       return ret;
-               else if (!ret)
-                       endpoint_not_ready = 0;
-       }
-
-       if (endpoint_not_ready)
-               return endpoint_not_ready;
-
-       rstc = devm_reset_control_get_exclusive(dev, NULL);
-
-       mutex_init(&ldev->err_lock);
+       /* Get number of endpoints */
+       nb_endpoints = of_graph_get_endpoint_count(np);
+       if (!nb_endpoints)
+               return -ENODEV;
 
        ldev->pixel_clk = devm_clk_get(dev, "lcd");
        if (IS_ERR(ldev->pixel_clk)) {
@@ -1244,6 +1226,43 @@ int ltdc_load(struct drm_device *ddev)
                return -ENODEV;
        }
 
+       /* Get endpoints if any */
+       for (i = 0; i < nb_endpoints; i++) {
+               ret = drm_of_find_panel_or_bridge(np, 0, i, &panel, &bridge);
+
+               /*
+                * If at least one endpoint is -ENODEV, continue probing,
+                * else if at least one endpoint returned an error
+                * (ie -EPROBE_DEFER) then stop probing.
+                */
+               if (ret == -ENODEV)
+                       continue;
+               else if (ret)
+                       goto err;
+
+               if (panel) {
+                       bridge = drm_panel_bridge_add_typed(panel,
+                                                           DRM_MODE_CONNECTOR_DPI);
+                       if (IS_ERR(bridge)) {
+                               DRM_ERROR("panel-bridge endpoint %d\n", i);
+                               ret = PTR_ERR(bridge);
+                               goto err;
+                       }
+               }
+
+               if (bridge) {
+                       ret = ltdc_encoder_init(ddev, bridge);
+                       if (ret) {
+                               DRM_ERROR("init encoder endpoint %d\n", i);
+                               goto err;
+                       }
+               }
+       }
+
+       rstc = devm_reset_control_get_exclusive(dev, NULL);
+
+       mutex_init(&ldev->err_lock);
+
        if (!IS_ERR(rstc)) {
                reset_control_assert(rstc);
                usleep_range(10, 20);
@@ -1285,27 +1304,7 @@ int ltdc_load(struct drm_device *ddev)
                        DRM_ERROR("Failed to register LTDC interrupt\n");
                        goto err;
                }
-       }
 
-       /* Add endpoints panels or bridges if any */
-       for (i = 0; i < MAX_ENDPOINTS; i++) {
-               if (panel[i]) {
-                       bridge[i] = drm_panel_bridge_add_typed(panel[i],
-                                                              DRM_MODE_CONNECTOR_DPI);
-                       if (IS_ERR(bridge[i])) {
-                               DRM_ERROR("panel-bridge endpoint %d\n", i);
-                               ret = PTR_ERR(bridge[i]);
-                               goto err;
-                       }
-               }
-
-               if (bridge[i]) {
-                       ret = ltdc_encoder_init(ddev, bridge[i]);
-                       if (ret) {
-                               DRM_ERROR("init encoder endpoint %d\n", i);
-                               goto err;
-                       }
-               }
        }
 
        crtc = devm_kzalloc(dev, sizeof(*crtc), GFP_KERNEL);
@@ -1340,8 +1339,8 @@ int ltdc_load(struct drm_device *ddev)
 
        return 0;
 err:
-       for (i = 0; i < MAX_ENDPOINTS; i++)
-               drm_panel_bridge_remove(bridge[i]);
+       for (i = 0; i < nb_endpoints; i++)
+               drm_of_panel_bridge_remove(ddev->dev->of_node, 0, i);
 
        clk_disable_unprepare(ldev->pixel_clk);
 
@@ -1350,11 +1349,14 @@ err:
 
 void ltdc_unload(struct drm_device *ddev)
 {
-       int i;
+       struct device *dev = ddev->dev;
+       int nb_endpoints, i;
 
        DRM_DEBUG_DRIVER("\n");
 
-       for (i = 0; i < MAX_ENDPOINTS; i++)
+       nb_endpoints = of_graph_get_endpoint_count(dev->of_node);
+
+       for (i = 0; i < nb_endpoints; i++)
                drm_of_panel_bridge_remove(ddev->dev->of_node, 0, i);
 
        pm_runtime_disable(ddev->dev);