[PATCH v2 1/2] drm/tegra: output: Support DRM bridges

[Dmitry Osipenko]

Newer Tegra device-trees will define a video output graph which involves
a bridge. This patch adds support for the DRM bridges to the Tegra's DRM
output.

Signed-off-by: Dmitry Osipenko <dig...@gmail.com>
---
 drivers/gpu/drm/tegra/drm.h    |  2 ++
 drivers/gpu/drm/tegra/output.c | 25 ++++++++++++++++++++++++-
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h
index ed99b67deb29..9ca11989679c 100644
--- a/drivers/gpu/drm/tegra/drm.h
+++ b/drivers/gpu/drm/tegra/drm.h
@@ -16,6 +16,7 @@
 #include <drm/drm_encoder.h>
 #include <drm/drm_fb_helper.h>
 #include <drm/drm_fixed.h>
+#include <drm/drm_of.h>
 #include <drm/drm_probe_helper.h>
 #include <uapi/drm/tegra_drm.h>
 
@@ -116,6 +117,7 @@ struct tegra_output {
        struct device_node *of_node;
        struct device *dev;
 
+       struct drm_bridge *bridge;
        struct drm_panel *panel;
        struct i2c_adapter *ddc;
        const struct edid *edid;
diff --git a/drivers/gpu/drm/tegra/output.c b/drivers/gpu/drm/tegra/output.c
index a264259b97a2..6b8fae4659b4 100644
--- a/drivers/gpu/drm/tegra/output.c
+++ b/drivers/gpu/drm/tegra/output.c
@@ -96,13 +96,28 @@ static irqreturn_t hpd_irq(int irq, void *data)
 
 int tegra_output_probe(struct tegra_output *output)
 {
-       struct device_node *ddc, *panel;
+       struct device_node *ddc, *panel, *port;
        unsigned long flags;
        int err, size;
 
        if (!output->of_node)
                output->of_node = output->dev->of_node;
 
+       /* newer device-trees may utilize output graph */
+       port = of_get_child_by_name(output->of_node, "port");
+       if (port) {
+               err = drm_of_find_panel_or_bridge(output->of_node, 0, 0,
+                                                 &output->panel,
+                                                 &output->bridge);
+               of_node_put(port);
+               if (err)
+                       return err;
+       }
+
+       if (output->panel || output->bridge)
+               goto edid_property;
+
+       /* for older device-trees we fall back to nvidia,panel */
        panel = of_parse_phandle(output->of_node, "nvidia,panel", 0);
        if (panel) {
                output->panel = of_drm_find_panel(panel);
@@ -112,6 +127,7 @@ int tegra_output_probe(struct tegra_output *output)
                of_node_put(panel);
        }
 
+edid_property:
        output->edid = of_get_property(output->of_node, "nvidia,edid", &size);
 
        ddc = of_parse_phandle(output->of_node, "nvidia,ddc-i2c-bus", 0);
@@ -189,6 +205,13 @@ int tegra_output_init(struct drm_device *drm, struct 
tegra_output *output)
                err = drm_panel_attach(output->panel, &output->connector);
                if (err < 0)
                        return err;
+       } else if (output->bridge) {
+               err = drm_bridge_attach(&output->encoder, output->bridge,
+                                       NULL, 0);
+               if (err) {
+                       dev_err(drm->dev, "cannot connect bridge: %d\n", err);
+                       return err;
+               }
        }
 
        /*
-- 
2.26.0

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