[PATCH 1/4] drm/i2c: tda998x: add a function for dynamic audio input switch

[Jean-Francois Moine]

When both I2S and S/PDIF are wired from the audio device to the
TDA998x, the user or some internal mechanism may choose to do audio
streaming via either inputs.

This patch adds an exported function in the TDA998x driver which
initializes the audio input parameters according to the audio
subsystem.

The audio format values in the encoder configuration interface  are
changed to non null values so that the value 0 is used in the audio
function to indicate that audio streaming is stopped.

Signed-off-by: Jean-Francois Moine <moinejf at free.fr>
---
 drivers/gpu/drm/i2c/tda998x_drv.c | 43 ++++++++++++++++++++++++++++++++++++++-
 include/drm/i2c/tda998x.h         |  7 +++++--
 2 files changed, 47 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i2c/tda998x_drv.c b/drivers/gpu/drm/i2c/tda998x_drv.c
index e5bbaf2..186c751 100644
--- a/drivers/gpu/drm/i2c/tda998x_drv.c
+++ b/drivers/gpu/drm/i2c/tda998x_drv.c
@@ -34,6 +34,7 @@ struct tda998x_priv {
 	struct i2c_client *hdmi;
 	uint16_t rev;
 	uint8_t current_page;
+	u8 audio_active;
 	int dpms;
 	bool is_hdmi_sink;
 	u8 vip_cntrl_0;
@@ -729,6 +730,38 @@ tda998x_configure_audio(struct tda998x_priv *priv,
 	tda998x_write_aif(priv, p);
 }
 
+/* tda998x codec interface */
+void tda998x_audio_update(struct i2c_client *client,
+			int format,
+			int port)
+{
+	struct tda998x_priv *priv = i2c_get_clientdata(client);
+	struct tda998x_encoder_params *p = &priv->params;
+
+	/* if the audio output is active, it may be a second start or a stop */
+	if (format == 0 || priv->audio_active) {
+		if (format == 0) {
+			priv->audio_active = 0;
+			reg_write(priv, REG_ENA_AP, 0);
+		}
+		return;
+	}
+
+	p->audio_cfg = port;
+
+	/* don't restart audio if same input format */
+	if (format == p->audio_format) {
+		priv->audio_active = 1;
+		reg_write(priv, REG_ENA_AP, p->audio_cfg);
+		return;
+	}
+	p->audio_format = format;
+	priv->audio_active = 1;
+
+	tda998x_configure_audio(priv, &priv->encoder->crtc->hwmode, p);
+}
+EXPORT_SYMBOL_GPL(tda998x_audio_update);
+
 /* DRM encoder functions */
 
 static void
@@ -751,6 +784,9 @@ tda998x_encoder_set_config(struct drm_encoder *encoder, void *params)
 			    (p->mirr_f ? VIP_CNTRL_2_MIRR_F : 0);
 
 	priv->params = *p;
+
+	if (p->audio_cfg)
+		priv->audio_active = 1;
 }
 
 static void
@@ -1001,7 +1037,7 @@ tda998x_encoder_mode_set(struct drm_encoder *encoder,
 
 		tda998x_write_avi(priv, adj_mode);
 
-		if (priv->params.audio_cfg)
+		if (priv->audio_active)
 			tda998x_configure_audio(priv, adj_mode, &priv->params);
 	}
 }
@@ -1233,10 +1269,15 @@ tda998x_encoder_init(struct i2c_client *client,
 	if (!priv)
 		return -ENOMEM;
 
+	i2c_set_clientdata(client, priv);
+
 	priv->vip_cntrl_0 = VIP_CNTRL_0_SWAP_A(2) | VIP_CNTRL_0_SWAP_B(3);
 	priv->vip_cntrl_1 = VIP_CNTRL_1_SWAP_C(0) | VIP_CNTRL_1_SWAP_D(1);
 	priv->vip_cntrl_2 = VIP_CNTRL_2_SWAP_E(4) | VIP_CNTRL_2_SWAP_F(5);
 
+	priv->params.audio_frame[1] = 1;		/* channels - 1 */
+	priv->params.audio_sample_rate = 48000;		/* 48kHz */
+
 	priv->current_page = 0xff;
 	priv->hdmi = client;
 	priv->cec = i2c_new_dummy(client->adapter, 0x34);
diff --git a/include/drm/i2c/tda998x.h b/include/drm/i2c/tda998x.h
index f3bb25c..0459931 100644
--- a/include/drm/i2c/tda998x.h
+++ b/include/drm/i2c/tda998x.h
@@ -19,11 +19,14 @@ struct tda998x_encoder_params {
 	u8 audio_frame[6];
 
 	enum {
-		AFMT_SPDIF,
-		AFMT_I2S
+		AFMT_I2S = 1,
+		AFMT_SPDIF
 	} audio_format;
 
 	unsigned audio_sample_rate;
 };
 
+void tda998x_audio_update(struct i2c_client *client,
+			int format,
+			int port);
 #endif
-- 
1.8.5.3