Make use of the em28xx chip configuration register to determine whether

From: Devin Heitmueller <devin.heitmueller@gmail.com>

we have AC97 audio, I2S audio, or no audio support at all.

Thanks for Ray Lu from Empia for providing the em2860/em2880 datasheet.

Signed-off-by: Devin Heitmueller <devin.heitmueller@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

3 files changed, 52 insertions, 1 deletions

diff --git a/linux/drivers/media/video/em28xx/em28xx-reg.h b/linux/drivers/media/video/em28xx/em28xx-reg.h
index 491d66abe..12c9132b0 100644
--- a/linux/drivers/media/video/em28xx/em28xx-reg.h
+++ b/linux/drivers/media/video/em28xx/em28xx-reg.h
@@ -17,6 +17,16 @@
 
 /* em28xx registers */
 
+#define EM28XX_R00_CHIPCFG	0x00
+
+/* em28xx Chip Configuration 0x00 */
+#define EM28XX_CHIPCFG_VENDOR_AUDIO		0x80
+#define EM28XX_CHIPCFG_I2S_VOLUME_CAPABLE	0x40
+#define EM28XX_CHIPCFG_I2S_3_SAMPRATES		0x30
+#define EM28XX_CHIPCFG_I2S_5_SAMPRATES		0x20
+#define EM28XX_CHIPCFG_AC97			0x10
+#define EM28XX_CHIPCFG_AUDIOMASK		0x30
+
 	/* GPIO/GPO registers */
 #define EM2880_R04_GPO	0x04    /* em2880-em2883 only */
 #define EM28XX_R08_GPIO	0x08	/* em2820 or upper */
diff --git a/linux/drivers/media/video/em28xx/em28xx-video.c b/linux/drivers/media/video/em28xx/em28xx-video.c
index 70d0bd086..d406fc224 100644
--- a/linux/drivers/media/video/em28xx/em28xx-video.c
+++ b/linux/drivers/media/video/em28xx/em28xx-video.c
@@ -1990,16 +1990,49 @@ static struct video_device *em28xx_vdev_init(struct em28xx *dev,
 
 int em28xx_supports_audio_extension(struct em28xx *dev)
 {
+	int rc;
+
 	/* The chip dictates whether we support the Empia analog audio
 	   extension */
 	switch (dev->chip_id) {
 	case CHIP_ID_EM2874:
-		/* Either a digital-only device or provides AC97 audio */
+		/* Digital only device - no analog support */
+		dev->audio_mode = EM28XX_NO_AUDIO;
 		return 0;
+	case CHIP_ID_EM2860:
 	case CHIP_ID_EM2883:
 	default:
+		/* See how this device is configured */
+		rc = em28xx_read_reg(dev, EM28XX_R00_CHIPCFG);
+		if (rc & EM28XX_CHIPCFG_VENDOR_AUDIO) {
+			switch(rc & EM28XX_CHIPCFG_AUDIOMASK) {
+			case EM28XX_CHIPCFG_AC97:
+				em28xx_info("AC97 audio (5 sample rates)\n");
+				dev->audio_mode = EM28XX_AC97;
+				break;
+			case EM28XX_CHIPCFG_I2S_3_SAMPRATES:
+				em28xx_info("I2S Audio (3 sample rates)\n");
+				dev->audio_mode = EM28XX_I2S_3_SAMPLE_RATES;
+				break;
+			case EM28XX_CHIPCFG_I2S_5_SAMPRATES:
+				em28xx_info("I2S Audio (5 sample rates)\n");
+				dev->audio_mode = EM28XX_I2S_5_SAMPLE_RATES;
+				break;
+			default:
+				em28xx_info("No audio support detected\n");
+				dev->audio_mode = EM28XX_NO_AUDIO;
+				return 0;
+			}
+		} else {
+			em28xx_info("USB Audio class device\n");
+			return 0;
+		}
+		/* The em28xx audio extension needs to be loaded */
 		return 1;
 	}
+
+	/* We should never reach this point */
+	return 0;
 }
 
 /*
diff --git a/linux/drivers/media/video/em28xx/em28xx.h b/linux/drivers/media/video/em28xx/em28xx.h
index 2ef7d0224..d272598c9 100644
--- a/linux/drivers/media/video/em28xx/em28xx.h
+++ b/linux/drivers/media/video/em28xx/em28xx.h
@@ -257,6 +257,13 @@ enum enum28xx_itype {
 	EM28XX_RADIO,
 };
 
+enum em28xx_audio_mode {
+	EM28XX_NO_AUDIO,
+	EM28XX_I2S_3_SAMPLE_RATES,
+	EM28XX_I2S_5_SAMPLE_RATES,
+	EM28XX_AC97,
+};
+
 enum em28xx_amux {
 	EM28XX_AMUX_VIDEO,
 	EM28XX_AMUX_LINE_IN,
@@ -412,6 +419,7 @@ struct em28xx {
 	u32 i2s_speed;		/* I2S speed for audio digital stream */
 
 	enum em28xx_decoder decoder;
+	enum em28xx_audio_mode audio_mode;
 
 	int tuner_type;		/* type of the tuner */
 	int tuner_addr;		/* tuner address */