drm/imx-ldb: Add support to drm-bridge

Add support to attach a drm_bridge to imx-ldb in addition to
existing support to attach a LVDS panel.

This patch does a simple code refactoring by moving code
from for_each_child_of_node iterator to a new function named
imx_ldb_panel_ddc(). This was necessary to allow the panel ddc
code to run only when the imx_ldb is not attached to a bridge.

Cc: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Rob Herring <robh@kernel.org>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Peter Senna Tschudin <peter.senna@collabora.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

1 files changed, 79 insertions, 41 deletions

diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c
index 7b588b44b845..4eed3a6addad 100644
--- a/drivers/gpu/drm/imx/imx-ldb.c
+++ b/drivers/gpu/drm/imx/imx-ldb.c
@@ -57,7 +57,11 @@ struct imx_ldb_channel {
         struct imx_ldb *ldb;
         struct drm_connector connector;
         struct drm_encoder encoder;
+
+        /* Defines what is connected to the ldb, only one at a time */
         struct drm_panel *panel;
+        struct drm_bridge *bridge;
+
         struct device_node *child;
         struct i2c_adapter *ddc;
         int chno;
@@ -468,10 +472,30 @@ static int imx_ldb_register(struct drm_device *drm,
         drm_encoder_init(drm, encoder, &imx_ldb_encoder_funcs,
                          DRM_MODE_ENCODER_LVDS, NULL);
 
-        drm_connector_helper_add(&imx_ldb_ch->connector,
-                        &imx_ldb_connector_helper_funcs);
-        drm_connector_init(drm, &imx_ldb_ch->connector,
-                           &imx_ldb_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
+        if (imx_ldb_ch->bridge) {
+                imx_ldb_ch->bridge->encoder = encoder;
+
+                imx_ldb_ch->encoder.bridge = imx_ldb_ch->bridge;
+                ret = drm_bridge_attach(drm, imx_ldb_ch->bridge);
+                if (ret) {
+                        DRM_ERROR("Failed to initialize bridge with drm\n");
+                        return ret;
+                }
+        } else {
+                /*
+                 * We want to add the connector whenever there is no bridge
+                 * that brings its own, not only when there is a panel. For
+                 * historical reasons, the ldb driver can also work without
+                 * a panel.
+                 */
+                drm_connector_helper_add(&imx_ldb_ch->connector,
+                                &imx_ldb_connector_helper_funcs);
+                drm_connector_init(drm, &imx_ldb_ch->connector,
+                                &imx_ldb_connector_funcs,
+                                DRM_MODE_CONNECTOR_LVDS);
+                drm_mode_connector_attach_encoder(&imx_ldb_ch->connector,
+                                encoder);
+        }
 
         if (imx_ldb_ch->panel) {
                 ret = drm_panel_attach(imx_ldb_ch->panel,
@@ -480,8 +504,6 @@ static int imx_ldb_register(struct drm_device *drm,
                         return ret;
         }
 
-        drm_mode_connector_attach_encoder(&imx_ldb_ch->connector, encoder);
-
         return 0;
 }
 
@@ -550,6 +572,46 @@ static const struct of_device_id imx_ldb_dt_ids[] = {
 };
 MODULE_DEVICE_TABLE(of, imx_ldb_dt_ids);
 
+static int imx_ldb_panel_ddc(struct device *dev,
+                struct imx_ldb_channel *channel, struct device_node *child)
+{
+        struct device_node *ddc_node;
+        const u8 *edidp;
+        int ret;
+
+        ddc_node = of_parse_phandle(child, "ddc-i2c-bus", 0);
+        if (ddc_node) {
+                channel->ddc = of_find_i2c_adapter_by_node(ddc_node);
+                of_node_put(ddc_node);
+                if (!channel->ddc) {
+                        dev_warn(dev, "failed to get ddc i2c adapter\n");
+                        return -EPROBE_DEFER;
+                }
+        }
+
+        if (!channel->ddc) {
+                /* if no DDC available, fallback to hardcoded EDID */
+                dev_dbg(dev, "no ddc available\n");
+
+                edidp = of_get_property(child, "edid",
+                                        &channel->edid_len);
+                if (edidp) {
+                        channel->edid = kmemdup(edidp,
+                                                channel->edid_len,
+                                                GFP_KERNEL);
+                } else if (!channel->panel) {
+                        /* fallback to display-timings node */
+                        ret = of_get_drm_display_mode(child,
+                                                      &channel->mode,
+                                                      &channel->bus_flags,
+                                                      OF_USE_NATIVE_MODE);
+                        if (!ret)
+                                channel->mode_valid = 1;
+                }
+        }
+        return 0;
+}
+
 static int imx_ldb_bind(struct device *dev, struct device *master, void *data)
 {
         struct drm_device *drm = data;
@@ -557,7 +619,6 @@ static int imx_ldb_bind(struct device *dev, struct device *master, void *data)
         const struct of_device_id *of_id =
                         of_match_device(imx_ldb_dt_ids, dev);
         struct device_node *child;
-        const u8 *edidp;
         struct imx_ldb *imx_ldb;
         int dual;
         int ret;
@@ -607,7 +668,6 @@ static int imx_ldb_bind(struct device *dev, struct device *master, void *data)
 
         for_each_child_of_node(np, child) {
                 struct imx_ldb_channel *channel;
-                struct device_node *ddc_node;
                 struct device_node *ep;
                 int bus_format;
 
@@ -640,47 +700,25 @@ static int imx_ldb_bind(struct device *dev, struct device *master, void *data)
 
                         remote = of_graph_get_remote_port_parent(ep);
                         of_node_put(ep);
-                        if (remote)
+                        if (remote) {
                                 channel->panel = of_drm_find_panel(remote);
-                        else
+                                channel->bridge = of_drm_find_bridge(remote);
+                        } else
                                 return -EPROBE_DEFER;
                         of_node_put(remote);
-                        if (!channel->panel) {
-                                dev_err(dev, "panel not found: %s\n",
-                                        remote->full_name);
-                                return -EPROBE_DEFER;
-                        }
-                }
 
-                ddc_node = of_parse_phandle(child, "ddc-i2c-bus", 0);
-                if (ddc_node) {
-                        channel->ddc = of_find_i2c_adapter_by_node(ddc_node);
-                        of_node_put(ddc_node);
-                        if (!channel->ddc) {
-                                dev_warn(dev, "failed to get ddc i2c adapter\n");
+                        if (!channel->panel && !channel->bridge) {
+                                dev_err(dev, "panel/bridge not found: %s\n",
+                                        remote->full_name);
                                 return -EPROBE_DEFER;
                         }
                 }
 
-                if (!channel->ddc) {
-                        /* if no DDC available, fallback to hardcoded EDID */
-                        dev_dbg(dev, "no ddc available\n");
-
-                        edidp = of_get_property(child, "edid",
-                                                &channel->edid_len);
-                        if (edidp) {
-                                channel->edid = kmemdup(edidp,
-                                                        channel->edid_len,
-                                                        GFP_KERNEL);
-                        } else if (!channel->panel) {
-                                /* fallback to display-timings node */
-                                ret = of_get_drm_display_mode(child,
-                                                              &channel->mode,
-                                                              &channel->bus_flags,
-                                                              OF_USE_NATIVE_MODE);
-                                if (!ret)
-                                        channel->mode_valid = 1;
-                        }
+                /* panel ddc only if there is no bridge */
+                if (!channel->bridge) {
+                        ret = imx_ldb_panel_ddc(dev, channel, child);
+                        if (ret)
+                                return ret;
                 }
 
                 bus_format = of_get_bus_format(dev, child);