Re: [PATCH V4 1/4] drm/imx-ldb: Add support to drm-bridge

From: Martyn Welch
Date: Tue Aug 16 2016 - 11:40:49 EST



On 04/08/16 23:36, Peter Senna Tschudin wrote:
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@xxxxxxxxxxxxx>
Cc: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
Cc: Rob Herring <robh@xxxxxxxxxx>
Cc: Fabio Estevam <fabio.estevam@xxxxxxx>
Cc: David Airlie <airlied@xxxxxxxx>
Cc: Thierry Reding <treding@xxxxxxxxxx>
Cc: Thierry Reding <thierry.reding@xxxxxxxxx>
Signed-off-by: Peter Senna Tschudin <peter.senna@xxxxxxxxxxxxx>

Acked-by: Martyn Welch <martyn.welch@xxxxxxxxxxxxxxx>

---
Changes from V3:
- The connector is created when there is no bridge instead of only when
there is a pannel
- Tested on next-20160804

Changes from V2:
- Updated to be aplied on top of Liu Ying changes that made imx-ldb atomic
- Tested on next-20160729

Changes from V1:
- Reanmed ext_bridge to bridge
- Removed empty entry point imx_ldb_encoder_enable()
- Adapted the code to apply to the latest linux next: next-20160609

drivers/gpu/drm/imx/imx-ldb.c | 118 ++++++++++++++++++++++++++++--------------
1 file changed, 78 insertions(+), 40 deletions(-)

diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c
index b03919e..4a33077 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;
@@ -466,10 +470,30 @@ 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,
@@ -478,8 +502,6 @@ static int imx_ldb_register(struct drm_device *drm,
return ret;
}

- drm_mode_connector_attach_encoder(&imx_ldb_ch->connector, encoder);
-
return 0;
}

@@ -548,6 +570,45 @@ 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,
+ 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;
@@ -555,7 +616,6 @@ 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;
@@ -605,7 +665,6 @@ 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;

@@ -638,46 +697,25 @@ 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,
- 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);