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>

diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c
index 7b588b4..4eed3a6 100644 (file)
--- 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);