drm/stm: ltdc: add a 2nd endpoint

ltdc can have up to 2 endpoints:
 - dpi external gpios: for rgb panels or external bridge ICs.
 - dpi internal ios: connected internally to dsi.

Note: Refer to the reference manual to know if the dsi is
present on your device.

Signed-off-by: Philippe Cornu <philippe.cornu@st.com>
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1509018489-19641-3-git-send-email-philippe.cornu@st.com

diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
index 7be6710a2450b2e90e50fe928f49cc2d47ea0281..35e884239f60b6b65b23085ba5cbfdf7b214fa87 100644 (file)
--- a/drivers/gpu/drm/stm/ltdc.c
+++ b/drivers/gpu/drm/stm/ltdc.c
@@ -33,6 +33,8 @@
 
 #define MAX_IRQ 4
 
+#define MAX_ENDPOINTS 2
+
 #define HWVER_10200 0x010200
 #define HWVER_10300 0x010300
 #define HWVER_20101 0x020101
@@ -856,18 +858,33 @@ 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;
-       struct drm_panel *panel;
+       struct drm_bridge *bridge[MAX_ENDPOINTS] = {NULL};
+       struct drm_panel *panel[MAX_ENDPOINTS] = {NULL};
        struct drm_crtc *crtc;
        struct reset_control *rstc;
        struct resource *res;
-       int irq, ret, i;
+       int irq, ret, i, endpoint_not_ready = -ENODEV;
 
        DRM_DEBUG_DRIVER("\n");
 
-       ret = drm_of_find_panel_or_bridge(np, 0, 0, &panel, &bridge);
-       if (ret)
-               return ret;
+       /* 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 ready, continue probing,
+                * else if at least one endpoint is -EPROBE_DEFER and
+                * there is no previous ready endpoints, defer probing.
+                */
+               if (!ret)
+                       endpoint_not_ready = 0;
+               else if (ret == -EPROBE_DEFER && endpoint_not_ready)
+                       endpoint_not_ready = -EPROBE_DEFER;
+       }
+
+       if (endpoint_not_ready)
+               return endpoint_not_ready;
 
        rstc = devm_reset_control_get_exclusive(dev, NULL);
 
@@ -928,19 +945,25 @@ int ltdc_load(struct drm_device *ddev)
 
        DRM_INFO("ltdc hw version 0x%08x - ready\n", ldev->caps.hw_version);
 
-       if (panel) {
-               bridge = drm_panel_bridge_add(panel, DRM_MODE_CONNECTOR_DPI);
-               if (IS_ERR(bridge)) {
-                       DRM_ERROR("Failed to create panel-bridge\n");
-                       ret = PTR_ERR(bridge);
-                       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(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;
+                       }
                }
-       }
 
-       ret = ltdc_encoder_init(ddev, bridge);
-       if (ret) {
-               DRM_ERROR("Failed to init encoder\n");
-               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);
@@ -968,7 +991,8 @@ int ltdc_load(struct drm_device *ddev)
        return 0;
 
 err:
-       drm_panel_bridge_remove(bridge);
+       for (i = 0; i < MAX_ENDPOINTS; i++)
+               drm_panel_bridge_remove(bridge[i]);
 
        clk_disable_unprepare(ldev->pixel_clk);
 
@@ -978,10 +1002,12 @@ err:
 void ltdc_unload(struct drm_device *ddev)
 {
        struct ltdc_device *ldev = ddev->dev_private;
+       int i;
 
        DRM_DEBUG_DRIVER("\n");
 
-       drm_of_panel_bridge_remove(ddev->dev->of_node, 0, 0);
+       for (i = 0; i < MAX_ENDPOINTS; i++)
+               drm_of_panel_bridge_remove(ddev->dev->of_node, 0, i);
 
        clk_disable_unprepare(ldev->pixel_clk);
 }