drm/omap: Reverse direction of the DSS device enable/disable operations

The omapdrm and omapdss drivers are architectured based on display
pipelines made of multiple components handled from sink (display) to
source (DSS output). This is incompatible with the DRM bridge and panel
APIs that handle components from source to sink.

Reconcile the omapdrm and omapdss drivers with the DRM bridge and panel
model by reversing the direction of the DSS device .enable() and
.disable() operations. This completes the move to the DRM bridge model,
with the notable exception of the DSI pipelines that will require more
work.

We also adapt the omapdss shutdown handler dss_shutdown() to shut down
all active pipelines starting from the pipeline output device instead of
the display device.

As a consequence the for_each_dss_display() macro isn't used and can be
removed, and the omapdss_device_get_next() function underlying the macro
can be simplified to search for output devices only.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Tested-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

1 files changed, 38 insertions, 11 deletions

diff --git a/drivers/gpu/drm/omapdrm/omap_encoder.c b/drivers/gpu/drm/omapdrm/omap_encoder.c
index d14d465392dd..acdfd2176423 100644
--- a/drivers/gpu/drm/omapdrm/omap_encoder.c
+++ b/drivers/gpu/drm/omapdrm/omap_encoder.c
@@ -146,33 +146,60 @@ static void omap_encoder_mode_set(struct drm_encoder *encoder,
 static void omap_encoder_disable(struct drm_encoder *encoder)
 {
         struct omap_encoder *omap_encoder = to_omap_encoder(encoder);
-        struct omap_dss_device *dssdev = omap_encoder->display;
+        struct omap_dss_device *dssdev = omap_encoder->output;
         struct drm_device *dev = encoder->dev;
 
         dev_dbg(dev->dev, "disable(%s)\n", dssdev->name);
 
-        dssdev->ops->disable(dssdev);
+        /*
+         * Disable the chain of external devices, starting at the one at the
+         * internal encoder's output.
+         */
+        omapdss_device_disable(dssdev->next);
+
+        /*
+         * Disable the internal encoder. This will disable the DSS output. The
+         * DSI is treated as an exception as DSI pipelines still use the legacy
+         * flow where the pipeline output controls the encoder.
+         */
+        if (dssdev->output_type != OMAP_DISPLAY_TYPE_DSI) {
+                dssdev->ops->disable(dssdev);
+                dssdev->state = OMAP_DSS_DISPLAY_DISABLED;
+        }
 
-        dssdev->state = OMAP_DSS_DISPLAY_DISABLED;
+        /*
+         * Perform the post-disable operations on the chain of external devices
+         * to complete the display pipeline disable.
+         */
+        omapdss_device_post_disable(dssdev->next);
 }
 
 static void omap_encoder_enable(struct drm_encoder *encoder)
 {
         struct omap_encoder *omap_encoder = to_omap_encoder(encoder);
-        struct omap_dss_device *dssdev = omap_encoder->display;
+        struct omap_dss_device *dssdev = omap_encoder->output;
         struct drm_device *dev = encoder->dev;
-        int r;
 
         dev_dbg(dev->dev, "enable(%s)\n", dssdev->name);
 
-        r = dssdev->ops->enable(dssdev);
-        if (r) {
-                dev_err(dev->dev, "Failed to enable display '%s': %d\n",
-                        dssdev->name, r);
-                return;
+        /* Prepare the chain of external devices for pipeline enable. */
+        omapdss_device_pre_enable(dssdev->next);
+
+        /*
+         * Enable the internal encoder. This will enable the DSS output. The
+         * DSI is treated as an exception as DSI pipelines still use the legacy
+         * flow where the pipeline output controls the encoder.
+         */
+        if (dssdev->output_type != OMAP_DISPLAY_TYPE_DSI) {
+                dssdev->ops->enable(dssdev);
+                dssdev->state = OMAP_DSS_DISPLAY_ACTIVE;
         }
 
-        dssdev->state = OMAP_DSS_DISPLAY_ACTIVE;
+        /*
+         * Enable the chain of external devices, starting at the one at the
+         * internal encoder's output.
+         */
+        omapdss_device_enable(dssdev->next);
 }
 
 static int omap_encoder_atomic_check(struct drm_encoder *encoder,