Re: [PATCH v2 2/3] drm/mediatek: Don't support hdmi connector creation

Dafna Hirschfeld <dafna.hirschfeld@xxxxxxxxxxxxx> · Tue, 30 Mar 2021 11:44:12 +0200

Hi,

On 30.03.21 02:08, Laurent Pinchart wrote:
Hi Dafna,

Thank you for the patch.

On Mon, Mar 29, 2021 at 05:36:31PM +0200, Dafna Hirschfeld wrote:
commit f01195148967 ("drm/mediatek: mtk_dpi: Create connector for bridges")
broke the display support for elm device since mtk_dpi calls
drm_bridge_attach with the flag DRM_BRIDGE_ATTACH_NO_CONNECTOR
while mtk_hdmi does not yet support this flag.

Fix this by accepting DRM_BRIDGE_ATTACH_NO_CONNECTOR in bridge attachment.
Implement the drm_bridge_funcs .detect() and .get_edid() operations, and
call drm_bridge_hpd_notify() to report HPD. This provides the
necessary API to support disabling connector creation.

This patch is inspired by a similar patch for bridge/synopsys/dw-hdmi.c:
commit ec971aaa6775 ("drm: bridge: dw-hdmi: Make connector creation optional")
But with the difference that in mtk-hdmi only the option of not creating
a connector is supported.

Fixes: f01195148967 ("drm/mediatek: mtk_dpi: Create connector for bridges")
Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@xxxxxxxxxxxxx>
---
  drivers/gpu/drm/mediatek/mtk_hdmi.c | 129 ++++++++++------------------
  1 file changed, 44 insertions(+), 85 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi.c b/drivers/gpu/drm/mediatek/mtk_hdmi.c
index f2c810b767ef..1eeb211b1536 100644
--- a/drivers/gpu/drm/mediatek/mtk_hdmi.c
+++ b/drivers/gpu/drm/mediatek/mtk_hdmi.c
@@ -186,11 +186,6 @@ static inline struct mtk_hdmi *hdmi_ctx_from_bridge(struct drm_bridge *b)
  	return container_of(b, struct mtk_hdmi, bridge);
  }
  
-static inline struct mtk_hdmi *hdmi_ctx_from_conn(struct drm_connector *c)
-{
-	return container_of(c, struct mtk_hdmi, conn);
-}
-
  static u32 mtk_hdmi_read(struct mtk_hdmi *hdmi, u32 offset)
  {
  	return readl(hdmi->regs + offset);
@@ -1201,48 +1196,30 @@ mtk_hdmi_update_plugged_status(struct mtk_hdmi *hdmi)
  	       connector_status_connected : connector_status_disconnected;
  }
  
-static enum drm_connector_status hdmi_conn_detect(struct drm_connector *conn,
-						  bool force)
-{
-	struct mtk_hdmi *hdmi = hdmi_ctx_from_conn(conn);
-	return mtk_hdmi_update_plugged_status(hdmi);
-}
-
-static void hdmi_conn_destroy(struct drm_connector *conn)
+static struct edid *mtk_hdmi_get_edid(struct mtk_hdmi *hdmi,
+				      struct drm_connector *connector)
  {
-	struct mtk_hdmi *hdmi = hdmi_ctx_from_conn(conn);
-
-	mtk_cec_set_hpd_event(hdmi->cec_dev, NULL, NULL);
-
-	drm_connector_cleanup(conn);
-}
-
-static int mtk_hdmi_conn_get_modes(struct drm_connector *conn)
-{
-	struct mtk_hdmi *hdmi = hdmi_ctx_from_conn(conn);
  	struct edid *edid;
-	int ret;
  
  	if (!hdmi->ddc_adpt)
-		return -ENODEV;
-
-	edid = drm_get_edid(conn, hdmi->ddc_adpt);
+		return NULL;
+	edid = drm_get_edid(connector, hdmi->ddc_adpt);
  	if (!edid)
-		return -ENODEV;
-
+		return NULL;
  	hdmi->dvi_mode = !drm_detect_monitor_audio(edid);
+	return edid;
+}
  
-	drm_connector_update_edid_property(conn, edid);
-
-	ret = drm_add_edid_modes(conn, edid);
-	kfree(edid);
-	return ret;
+static enum drm_connector_status mtk_hdmi_detect(struct mtk_hdmi *hdmi)
+{
+	return mtk_hdmi_update_plugged_status(hdmi);
  }
  
-static int mtk_hdmi_conn_mode_valid(struct drm_connector *conn,
-				    struct drm_display_mode *mode)
+static int mtk_hdmi_bridge_mode_valid(struct drm_bridge *bridge,
+				      const struct drm_display_info *info,
+				      const struct drm_display_mode *mode)
  {
-	struct mtk_hdmi *hdmi = hdmi_ctx_from_conn(conn);
+	struct mtk_hdmi *hdmi = hdmi_ctx_from_bridge(bridge);
  	struct drm_bridge *next_bridge;
  
  	dev_dbg(hdmi->dev, "xres=%d, yres=%d, refresh=%d, intl=%d clock=%d\n",
@@ -1267,74 +1244,50 @@ static int mtk_hdmi_conn_mode_valid(struct drm_connector *conn,
  	return drm_mode_validate_size(mode, 0x1fff, 0x1fff);
  }
  
-static struct drm_encoder *mtk_hdmi_conn_best_enc(struct drm_connector *conn)
-{
-	struct mtk_hdmi *hdmi = hdmi_ctx_from_conn(conn);
-
-	return hdmi->bridge.encoder;
-}
-
-static const struct drm_connector_funcs mtk_hdmi_connector_funcs = {
-	.detect = hdmi_conn_detect,
-	.fill_modes = drm_helper_probe_single_connector_modes,
-	.destroy = hdmi_conn_destroy,
-	.reset = drm_atomic_helper_connector_reset,
-	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
-	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
-};
-
-static const struct drm_connector_helper_funcs
-		mtk_hdmi_connector_helper_funcs = {
-	.get_modes = mtk_hdmi_conn_get_modes,
-	.mode_valid = mtk_hdmi_conn_mode_valid,
-	.best_encoder = mtk_hdmi_conn_best_enc,
-};
-
  static void mtk_hdmi_hpd_event(bool hpd, struct device *dev)
  {
  	struct mtk_hdmi *hdmi = dev_get_drvdata(dev);
  
-	if (hdmi && hdmi->bridge.encoder && hdmi->bridge.encoder->dev)
+	if (hdmi && hdmi->bridge.encoder && hdmi->bridge.encoder->dev) {
+		static enum drm_connector_status status;
+
+		status = mtk_hdmi_detect(hdmi);
  		drm_helper_hpd_irq_event(hdmi->bridge.encoder->dev);

I think you can drop this, as drm_bridge_connector_hpd_cb() calls
drm_kms_helper_hotplug_event().

I see that drm_kms_helper_hotplug_event is called from drm_bridge_connector_hpd_cb,
which is set as a birdge's 'hpd_cb' when calling drm_bridge_connector_enable_hpd,
but mkt_dpi does not call this funcion for the drm_bridge_connector.

I also wonder why bridges have both 'hpd_cb' and a function 'hpd_notify'.
It seems that both are called upon hot-plug event.
It is also confusing that the function drm_bridge_hpd_notify calls the 'hpd_cb'
and not the 'hpd_notfiy'. I can send a patch to change the name to 'drm_bridge_hpd_cb'

Thanks,
Dafna


+		drm_bridge_hpd_notify(&hdmi->bridge, status);
+	}
  }
  
  /*
   * Bridge callbacks
   */
  
+static enum drm_connector_status mtk_hdmi_bridge_detect(struct drm_bridge *bridge)
+{
+	struct mtk_hdmi *hdmi = hdmi_ctx_from_bridge(bridge);
+
+	return mtk_hdmi_detect(hdmi);
+}
+
+static struct edid *mtk_hdmi_bridge_get_edid(struct drm_bridge *bridge,
+					     struct drm_connector *connector)
+{
+	struct mtk_hdmi *hdmi = hdmi_ctx_from_bridge(bridge);
+
+	return mtk_hdmi_get_edid(hdmi, connector);

As mtk_hdmi_get_edid() is only called here, you could inline it in this
function. Up to you.

+}
+
  static int mtk_hdmi_bridge_attach(struct drm_bridge *bridge,
  				  enum drm_bridge_attach_flags flags)
  {
  	struct mtk_hdmi *hdmi = hdmi_ctx_from_bridge(bridge);
  	int ret;
  
-	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
-		DRM_ERROR("Fix bridge driver to make connector optional!");
+	if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)) {
+		DRM_ERROR("%s: The flag DRM_BRIDGE_ATTACH_NO_CONNECTOR must be supplied\n",
+			  __func__);
  		return -EINVAL;
  	}
  
-	ret = drm_connector_init_with_ddc(bridge->encoder->dev, &hdmi->conn,
-					  &mtk_hdmi_connector_funcs,
-					  DRM_MODE_CONNECTOR_HDMIA,
-					  hdmi->ddc_adpt);
-	if (ret) {
-		dev_err(hdmi->dev, "Failed to initialize connector: %d\n", ret);
-		return ret;
-	}
-	drm_connector_helper_add(&hdmi->conn, &mtk_hdmi_connector_helper_funcs);
-
-	hdmi->conn.polled = DRM_CONNECTOR_POLL_HPD;
-	hdmi->conn.interlace_allowed = true;
-	hdmi->conn.doublescan_allowed = false;
-
-	ret = drm_connector_attach_encoder(&hdmi->conn,
-						bridge->encoder);
-	if (ret) {
-		dev_err(hdmi->dev,
-			"Failed to attach connector to encoder: %d\n", ret);
-		return ret;
-	}
-
  	if (hdmi->next_bridge) {
  		ret = drm_bridge_attach(bridge->encoder, hdmi->next_bridge,
  					bridge, flags);
@@ -1444,6 +1397,7 @@ static void mtk_hdmi_bridge_atomic_enable(struct drm_bridge *bridge,
  }
  
  static const struct drm_bridge_funcs mtk_hdmi_bridge_funcs = {
+	.mode_valid = mtk_hdmi_bridge_mode_valid,
  	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
  	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
  	.atomic_reset = drm_atomic_helper_bridge_reset,
@@ -1454,6 +1408,8 @@ static const struct drm_bridge_funcs mtk_hdmi_bridge_funcs = {
  	.mode_set = mtk_hdmi_bridge_mode_set,
  	.atomic_pre_enable = mtk_hdmi_bridge_atomic_pre_enable,
  	.atomic_enable = mtk_hdmi_bridge_atomic_enable,
+	.detect = mtk_hdmi_bridge_detect,
+	.get_edid = mtk_hdmi_bridge_get_edid,
  };
  
  static int mtk_hdmi_dt_parse_pdata(struct mtk_hdmi *hdmi,
@@ -1762,6 +1718,9 @@ static int mtk_drm_hdmi_probe(struct platform_device *pdev)
  
  	hdmi->bridge.funcs = &mtk_hdmi_bridge_funcs;
  	hdmi->bridge.of_node = pdev->dev.of_node;
+	hdmi->bridge.ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID
+			   | DRM_BRIDGE_OP_HPD;

Nitpicking, I'd align the | to the =.

Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>

+	hdmi->bridge.type = DRM_MODE_CONNECTOR_HDMIA;
  	drm_bridge_add(&hdmi->bridge);
  
  	ret = mtk_hdmi_clk_enable_audio(hdmi);

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