drm/mediatek: support HDMI jack status reporting

1.
Provides a callback (i.e. mtk_hdmi_audio_hook_plugged_cb) to hdmi-codec.
When ASoC machine driver calls hdmi_codec_set_jack_detect(), the
callback will be invoked to save plugged_cb and codec_dev parameters.

+---------+  set_jack_  +------------+ plugged_cb  +----------+
| machine | ----------> | hdmi-codec | ----------> | mtk-hdmi |
+---------+  detect()   +------------+ codec_dev   +----------+

2.
When there is any jack status changes, mtk-hdmi will call the
plugged_cb() to notify hdmi-codec.  And then hdmi-codec will call
snd_soc_jack_report().

+----------+ plugged_cb  +------------+
| mtk-hdmi | ----------> | hdmi-codec | -> snd_soc_jack_report()
+----------+ codec_dev   +------------+
             connector_status
Signed-off-by: Tzung-Bi Shih <tzungbi@google.com>
Link: https://lore.kernel.org/r/20200206102509.2.I230fd59de28e73934a91cb01424e25b9e84727f4@changeidSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/gpu/drm/mediatek/mtk_hdmi.c

@@ -169,6 +169,8 @@ struct mtk_hdmi {
 	bool audio_enable;
 	bool powered;
 	bool enabled;
+	hdmi_codec_plugged_cb plugged_cb;
+	struct device *codec_dev;
 };
 
 static inline struct mtk_hdmi *hdmi_ctx_from_bridge(struct drm_bridge *b)
@@ -1194,13 +1196,23 @@ static void mtk_hdmi_clk_disable_audio(struct mtk_hdmi *hdmi)
 	clk_disable_unprepare(hdmi->clk[MTK_HDMI_CLK_AUD_SPDIF]);
 }
 
+static enum drm_connector_status
+mtk_hdmi_update_plugged_status(struct mtk_hdmi *hdmi)
+{
+	bool connected = mtk_cec_hpd_high(hdmi->cec_dev);
+
+	if (hdmi->plugged_cb && hdmi->codec_dev)
+		hdmi->plugged_cb(hdmi->codec_dev, connected);
+
+	return connected ?
+	       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_cec_hpd_high(hdmi->cec_dev) ?
-	       connector_status_connected : connector_status_disconnected;
+	return mtk_hdmi_update_plugged_status(hdmi);
 }
 
 static void hdmi_conn_destroy(struct drm_connector *conn)
@@ -1651,20 +1663,36 @@ static int mtk_hdmi_audio_get_eld(struct device *dev, void *data, uint8_t *buf,
 	return 0;
 }
 
+static int mtk_hdmi_audio_hook_plugged_cb(struct device *dev, void *data,
+					  hdmi_codec_plugged_cb fn,
+					  struct device *codec_dev)
+{
+	struct mtk_hdmi *hdmi = data;
+
+	hdmi->plugged_cb = fn;
+	hdmi->codec_dev = codec_dev;
+	mtk_hdmi_update_plugged_status(hdmi);
+
+	return 0;
+}
+
 static const struct hdmi_codec_ops mtk_hdmi_audio_codec_ops = {
 	.hw_params = mtk_hdmi_audio_hw_params,
 	.audio_startup = mtk_hdmi_audio_startup,
 	.audio_shutdown = mtk_hdmi_audio_shutdown,
 	.digital_mute = mtk_hdmi_audio_digital_mute,
 	.get_eld = mtk_hdmi_audio_get_eld,
+	.hook_plugged_cb = mtk_hdmi_audio_hook_plugged_cb,
 };
 
 static int mtk_hdmi_register_audio_driver(struct device *dev)
 {
+	struct mtk_hdmi *hdmi = dev_get_drvdata(dev);
 	struct hdmi_codec_pdata codec_data = {
 		.ops = &mtk_hdmi_audio_codec_ops,
 		.max_i2s_channels = 2,
 		.i2s = 1,
+		.data = hdmi,
 	};
 	struct platform_device *pdev;