Nova-S-Plus audio line input

Hi everyone,

This patch adds audio DMA capture and ALSA mixer elements for the line input jack of the Hauppauge Nova-S-plus DVB-S PCI card.

I'm using a Hauppauge Nova-S-plus PCI card to watch sat TV and it's been very robust - thanks to everyone here. I have one minor niggle - when I use it with composite video input from an external STB I can't connect the audio to the line input jack on the card. So I developed this patch, originally in late 2008 with lots of feedback and input from Darron Broad.

The Nova-S-plus has a WM8775 ADC that is currently not detected. This patch enables this chip and exports elements for ALSA mixer controls.

I've used this patch with kernels from 2.6.24 to 2.6.35-rc6 and I'm just a little tired of tweaking it every time a new kernel comes out so I'm hoping that it can be permanently included.

Signed-off by Lawrence Rust <lawrence (at) softsystem.co.uk>

drivers/media/video/cx88/cx88-alsa.c +14 -0

index 33082c9..044516b 100644
@@ -588,6 +588,30 @@ static int snd_cx88_volume_put(struct snd_kcontrol *kcontrol,
 	int changed = 0;
 	u32 old;
 
+    /* If a WM8775 is used for audio input utilise the audio controls */
+    if ( core->board.audio_chip && core->board.audio_chip == V4L2_IDENT_WM8775) {
+        struct v4l2_control client_ctl;
+
+        if ( value->value.integer.value[0] >= value->value.integer.value[1]) {
+            v = value->value.integer.value[0] << 10;
+            b = value->value.integer.value[0] ?
+              (0x8000 * value->value.integer.value[1]) / value->value.integer.value[0] :
+              0x8000;
+        } else {
+            v = value->value.integer.value[1] << 10;
+            b = value->value.integer.value[1] ?
+              0xffff - (0x8000 * value->value.integer.value[0]) / value->value.integer.value[1] :
+              0x8000;

drivers/media/video/cx88/cx88-alsa.c +2 -2

 	left = value->value.integer.value[0] & 0x3f;
 	right = value->value.integer.value[1] & 0x3f;
 	b = right - left;

@@ -601,10 +625,10 @@ static int snd_cx88_volume_put(struct snd_kcontrol *kcontrol,
 	spin_lock_irq(&chip->reg_lock);
 	old = cx_read(AUD_VOL_CTL);
 	if (v != (old & 0x3f)) {
-	    cx_write(AUD_VOL_CTL, (old & ~0x3f) | v);
+        cx_swrite(SHADOW_AUD_VOL_CTL, AUD_VOL_CTL, (old & ~0x3f) | v);
 	    changed = 1;
 	}
-	if (cx_read(AUD_BAL_CTL) != b) {
+    if ((cx_read(AUD_BAL_CTL) & 0x7f) != b) {
 	    cx_write(AUD_BAL_CTL, b);
 	    changed = 1;
 	}

drivers/media/video/cx88/cx88-alsa.c +0 -0

 	.info = snd_cx88_volume_info,
 	.get = snd_cx88_volume_get,
 	.put = snd_cx88_volume_put,

@@ -650,7 +674,14 @@ static int snd_cx88_switch_put(struct snd_kcontrol *kcontrol,
 	vol = cx_read(AUD_VOL_CTL);
 	if (value->value.integer.value[0] != !(vol & bit)) {

drivers/media/video/cx88/cx88-cards.c +7 -0

 		.radio_type	= UNSET,
 		.tuner_addr	= ADDR_UNSET,
 		.radio_addr	= ADDR_UNSET,
+        .audio_chip = V4L2_IDENT_WM8775,
 		.input		= {{
 			.type	= CX88_VMUX_DVB,
 			.vmux	= 0,
+            /* 2: Line-In */
+            .audioroute = 2,
 		},{
 			.type	= CX88_VMUX_COMPOSITE1,
 			.vmux	= 1,
+            /* 2: Line-In */
+            .audioroute = 2,
 		},{
 			.type	= CX88_VMUX_SVIDEO,
 			.vmux	= 2,
+            /* 2: Line-In */
+            .audioroute = 2,
 		}},
 		.mpeg           = CX88_MPEG_DVB,
 	},

drivers/media/video/cx88/cx88-video.c +15 -0

index 0fab65c..2c5bd14 100644
@@ -992,6 +992,32 @@ int cx88_set_control(struct cx88_core *core, struct v4l2_control *ctl)
 		ctl->value = c->v.minimum;
 	if (ctl->value > c->v.maximum)
 		ctl->value = c->v.maximum;
+
+	/* If a WM8775 is used for audio input utilise the audio controls */
+	if (core->board.audio_chip &&
+			core->board.audio_chip == V4L2_IDENT_WM8775) {
+		struct v4l2_control client_ctl;
+
+		client_ctl.id = ctl->id;
+		switch (ctl->id) {
+			case V4L2_CID_AUDIO_MUTE:
+				client_ctl.value = ctl->value;
+				break;
+			case V4L2_CID_AUDIO_VOLUME:
+				client_ctl.value = (ctl->value) ?
+					(0x90 + ctl->value) << 8 : 0;
+				break;

drivers/media/video/cx88/cx88-video.c +3 -1

 	mask=c->mask;
 	switch (ctl->id) {
 	case V4L2_CID_AUDIO_BALANCE:

@@ -1537,7 +1563,9 @@ static int radio_queryctrl (struct file *file, void *priv,
 	if (c->id <  V4L2_CID_BASE ||
 		c->id >= V4L2_CID_LASTP1)
 		return -EINVAL;
-	if (c->id == V4L2_CID_AUDIO_MUTE) {
+	if (c->id == V4L2_CID_AUDIO_MUTE ||
+		c->id == V4L2_CID_AUDIO_VOLUME ||
+			c->id == V4L2_CID_AUDIO_BALANCE) {
 		for (i = 0; i < CX8800_CTLS; i++) {
 			if (cx8800_ctls[i].v.id == c->id)
 				break;

drivers/media/video/wm8775.c +2 -0

index 5c2ba59..140e54a 100644
@@ -55,6 +55,8 @@ struct wm8775_state {
 	struct v4l2_subdev sd;
 	u8 input;		/* Last selected input (0-0xf) */
 	u8 muted;
+    u16 volume;
+    u16 balance;
 };
 
 static inline struct wm8775_state *to_state(struct v4l2_subdev *sd)

@@ -80,6 +82,27 @@ static int wm8775_write(struct v4l2_subdev *sd, int reg, u16 val)
 	return -1;
 }

drivers/media/video/wm8775.c +5 -0

+    /* Un-mute */
+    if (!state->muted)
+      wm8775_write(sd, R21, state->input);
+}
+
 static int wm8775_s_routing(struct v4l2_subdev *sd,
 			    u32 input, u32 output, u32 config)
 {

drivers/media/video/wm8775.c +25 -11

 	return 0;
 }
 

@@ -108,9 +126,23 @@ static int wm8775_g_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl)
 {
 	struct wm8775_state *state = to_state(sd);
 
-	if (ctrl->id != V4L2_CID_AUDIO_MUTE)
-		return -EINVAL;
-	ctrl->value = state->muted;
+    switch (ctrl->id) {
+    case V4L2_CID_AUDIO_MUTE:
+        ctrl->value = state->muted;
+        break;
+
+    case V4L2_CID_AUDIO_VOLUME:
+        ctrl->value = state->volume;
+        break;
+
+    case V4L2_CID_AUDIO_BALANCE:
+        ctrl->value = state->balance;
+        break;
+
+    default:
+        return -EINVAL;
+    }
+
 	return 0;
 }
 

@@ -118,14 +150,24 @@ static int wm8775_s_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl)
 {
 	struct wm8775_state *state = to_state(sd);
 
-	if (ctrl->id != V4L2_CID_AUDIO_MUTE)
-		return -EINVAL;
-	state->muted = ctrl->value;
-	wm8775_write(sd, R21, 0x0c0);
-	wm8775_write(sd, R14, 0x1d4);
-	wm8775_write(sd, R15, 0x1d4);
-	if (!state->muted)
-		wm8775_write(sd, R21, 0x100 + state->input);
+    switch (ctrl->id) {
+    case V4L2_CID_AUDIO_MUTE:
+        state->muted = ctrl->value;
+        break;
+
+    case V4L2_CID_AUDIO_VOLUME:
+        state->volume = ctrl->value;
+        break;

drivers/media/video/wm8775.c +3 -3

 	return 0;
 }
 

@@ -140,31 +182,71 @@ static int wm8775_log_status(struct v4l2_subdev *sd)
 {
 	struct wm8775_state *state = to_state(sd);
 
-	v4l2_info(sd, "Input: %d%s\n", state->input,
-			state->muted ? " (muted)" : "");
+        v4l2_info(sd, "Volume: %04x%s Balance: %04x Input: %d\n",
+                state->volume, state->muted ? " (muted)" : "",
+                state->balance, state->input);
 	return 0;
 }
 
 static int wm8775_s_frequency(struct v4l2_subdev *sd, struct v4l2_frequency *freq)
 {
-	struct wm8775_state *state = to_state(sd);

drivers/media/video/wm8775.c +48 -27

 	return 0;
 }
 
+static struct v4l2_queryctrl wm8775_qctrl[] = {
+       {
+               .id            = V4L2_CID_AUDIO_VOLUME,
+               .name          = "Volume",
+               .minimum       = 0,
+               .maximum       = 65535,
+               .step          = 65535/100,
+               .default_value = 0xCF00, /* 0 dB */
+               .flags         = 0,
+               .type          = V4L2_CTRL_TYPE_INTEGER,
+       }, {
+               .id            = V4L2_CID_AUDIO_MUTE,
+               .name          = "Mute",
+               .minimum       = 0,
+               .maximum       = 1,
+               .step          = 1,
+               .default_value = 1,
+               .flags         = 0,
+               .type          = V4L2_CTRL_TYPE_BOOLEAN,
+       }, {
+               .id            = V4L2_CID_AUDIO_BALANCE,
+               .name          = "Balance",
+               .minimum       = 0,
+               .maximum       = 65535,
+               .step          = 65535/100,
+               .default_value = 32768,
+               .flags         = 0,
+               .type          = V4L2_CTRL_TYPE_INTEGER,
+       }
+};
+
+static int wm8775_query_ctrl(struct v4l2_subdev *sd, struct v4l2_queryctrl *qc)
+{
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(wm8775_qctrl); i++)
+        if (qc->id && qc->id == wm8775_qctrl[i].id) {
+            memcpy(qc, &wm8775_qctrl[i], sizeof(*qc));
+            return 0;
+        }
+    return -EINVAL;
+}
+
 /* ----------------------------------------------------------------------- */
 
 static const struct v4l2_subdev_core_ops wm8775_core_ops = {
 	.log_status = wm8775_log_status,
 	.g_chip_ident = wm8775_g_chip_ident,
+        .queryctrl = wm8775_query_ctrl,
 	.g_ctrl = wm8775_g_ctrl,
 	.s_ctrl = wm8775_s_ctrl,
 };

@@ -212,36 +294,23 @@ static int wm8775_probe(struct i2c_client *client,
 	v4l2_i2c_subdev_init(sd, client, &wm8775_ops);
 	state->input = 2;
 	state->muted = 0;
+    state->volume = 0xCF00;
+    state->balance = 0x8000;
 
 	/* Initialize wm8775 */
 
-	/* RESET */
-	wm8775_write(sd, R23, 0x000);
-	/* Disable zero cross detect timeout */
-	wm8775_write(sd, R7, 0x000);
-	/* Left justified, 24-bit mode */
-	wm8775_write(sd, R11, 0x021);
-	/* Master mode, clock ratio 256fs */
-	wm8775_write(sd, R12, 0x102);
-	/* Powered up */
-	wm8775_write(sd, R13, 0x000);
-	/* ADC gain +2.5dB, enable zero cross */
-	wm8775_write(sd, R14, 0x1d4);
-	/* ADC gain +2.5dB, enable zero cross */
-	wm8775_write(sd, R15, 0x1d4);
-	/* ALC Stereo, ALC target level -1dB FS max gain +8dB */
-	wm8775_write(sd, R16, 0x1bf);
-	/* Enable gain control, use zero cross detection,
-	   ALC hold time 42.6 ms */
-	wm8775_write(sd, R17, 0x185);
-	/* ALC gain ramp up delay 34 s, ALC gain ramp down delay 33 ms */
-	wm8775_write(sd, R18, 0x0a2);
-	/* Enable noise gate, threshold -72dBfs */
-	wm8775_write(sd, R19, 0x005);
-	/* Transient window 4ms, lower PGA gain limit -1dB */
-	wm8775_write(sd, R20, 0x07a);
-	/* LRBOTH = 1, use input 2. */
-	wm8775_write(sd, R21, 0x102);
+    wm8775_write(sd, R23, 0x000); /* RESET */
+    wm8775_write(sd, R11, 0x022); /* HPF enable, I2S mode, 24-bit */

drivers/media/video/wm8775.c +0 -1

 	return 0;
 }
 
 
 
--

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Quoted 44 lines · lawrence rust

Hi everyone,

This patch adds audio DMA capture and ALSA mixer elements for the line input jack of the Hauppauge Nova-S-plus DVB-S PCI card.

I'm using a Hauppauge Nova-S-plus PCI card to watch sat TV and it's been very robust - thanks to everyone here. I have one minor niggle - when I use it with composite video input from an external STB I can't connect the audio to the line input jack on the card. So I developed this patch, originally in late 2008 with lots of feedback and input from Darron Broad.

The Nova-S-plus has a WM8775 ADC that is currently not detected. This patch enables this chip and exports elements for ALSA mixer controls.

I've used this patch with kernels from 2.6.24 to 2.6.35-rc6 and I'm just a little tired of tweaking it every time a new kernel comes out so I'm hoping that it can be permanently included.

Signed-off by Lawrence Rust <lawrence (at) softsystem.co.uk>

drivers/media/video/cx88/cx88-alsa.c +14 -0

index 33082c9..044516b 100644
@@ -588,6 +588,30 @@ static int snd_cx88_volume_put(struct snd_kcontrol *kcontrol,
 	int changed = 0;
 	u32 old;
 
+    /* If a WM8775 is used for audio input utilise the audio controls */
+    if ( core->board.audio_chip && core->board.audio_chip == V4L2_IDENT_WM8775) {
+        struct v4l2_control client_ctl;
+
+        if ( value->value.integer.value[0] >= value->value.integer.value[1]) {
+            v = value->value.integer.value[0] << 10;
+            b = value->value.integer.value[0] ?
+              (0x8000 * value->value.integer.value[1]) / value->value.integer.value[0] :
+              0x8000;
+        } else {
+            v = value->value.integer.value[1] << 10;
+            b = value->value.integer.value[1] ?
+              0xffff - (0x8000 * value->value.integer.value[0]) / value->value.integer.value[1] :
+              0x8000;

drivers/media/video/cx88/cx88-alsa.c static int snd_cx88_volume_put(struct snd_kcontrol *kcontrol, · line 614

Quoted 10 lines

drivers/media/video/cx88/cx88-alsa.c +10 -0

+        }
+        client_ctl.value = v;
+        client_ctl.id = V4L2_CID_AUDIO_VOLUME;
+        call_all(core, core, s_ctrl, &client_ctl);
+
+        client_ctl.value = b;
+        client_ctl.id = V4L2_CID_AUDIO_BALANCE;
+        call_all(core, core, s_ctrl, &client_ctl);
+    }
+

With the subdev construct, there is really no need for the conditional check on the chip's existence. Just do the call_all().

Or better yet, when the audio control subdevice is instantiated, squirrel away a v4l2_subdev * to it in the card's instance structure and just use that instead of "call_all()". Or when the subdev is instantiated, mark the subdev's grp_id with some sort of WM8775 or audio control marker value and call the subdev by grp_ip match. Using call_all() isn't the best thing to do, when you know you're just after one or two specific devices.

Quoted 18 lines

drivers/media/video/cx88/cx88-alsa.c +2 -2

 	left = value->value.integer.value[0] & 0x3f;
 	right = value->value.integer.value[1] & 0x3f;
 	b = right - left;

@@ -601,10 +625,10 @@ static int snd_cx88_volume_put(struct snd_kcontrol *kcontrol,
 	spin_lock_irq(&chip->reg_lock);
 	old = cx_read(AUD_VOL_CTL);
 	if (v != (old & 0x3f)) {
-	    cx_write(AUD_VOL_CTL, (old & ~0x3f) | v);
+        cx_swrite(SHADOW_AUD_VOL_CTL, AUD_VOL_CTL, (old & ~0x3f) | v);
 	    changed = 1;
 	}
-	if (cx_read(AUD_BAL_CTL) != b) {
+    if ((cx_read(AUD_BAL_CTL) & 0x7f) != b) {
 	    cx_write(AUD_BAL_CTL, b);
 	    changed = 1;
 	}

@@ -619,7 +643,7 @@ static struct snd_kcontrol_new snd_cx88_volume = {

drivers/media/video/cx88/cx88-alsa.c static struct snd_kcontrol_new snd_cx88_volume = { · line 646

Quoted 5 lines

drivers/media/video/cx88/cx88-alsa.c +1 -1

 	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
 	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
 		  SNDRV_CTL_ELEM_ACCESS_TLV_READ,
-	.name = "Playback Volume",
+	.name = "Tuner Volume",

I'd call this "Analog TV Capture Volume" myself, but meh, it doesn't really matter.

Quoted 11 lines

drivers/media/video/cx88/cx88-alsa.c +2 -1

 	.info = snd_cx88_volume_info,
 	.get = snd_cx88_volume_get,
 	.put = snd_cx88_volume_put,

@@ -650,7 +674,14 @@ static int snd_cx88_switch_put(struct snd_kcontrol *kcontrol,
 	vol = cx_read(AUD_VOL_CTL);
 	if (value->value.integer.value[0] != !(vol & bit)) {
 		vol ^= bit;
-		cx_write(AUD_VOL_CTL, vol);
+        cx_swrite(SHADOW_AUD_VOL_CTL, AUD_VOL_CTL, vol);
+        /* If a WM8775 is used for audio input utilise the audio controls */

drivers/media/video/cx88/cx88-alsa.c static int snd_cx88_switch_put(struct snd_kcontrol *kcontrol, · line 684

Quoted 6 lines

drivers/media/video/cx88/cx88-alsa.c +6 -0

+        if ( (1<<6) == bit && core->board.audio_chip && core->board.audio_chip == V4L2_IDENT_WM8775) {
+            struct v4l2_control client_ctl;
+            client_ctl.value = 0 == value->value.integer.value[0];
+            client_ctl.id = V4L2_CID_AUDIO_MUTE;
+            call_all(core, core, s_ctrl, &client_ctl);
+        }

My previous comment abouit calling subdevs applies here.

Quoted 5 lines

drivers/media/video/cx88/cx88-alsa.c +0 -0

 		ret = 1;
 	}
 	spin_unlock_irq(&chip->reg_lock);

@@ -659,7 +690,7 @@ static int snd_cx88_switch_put(struct snd_kcontrol *kcontrol,
 

drivers/media/video/cx88/cx88-alsa.c static int snd_cx88_switch_put(struct snd_kcontrol *kcontrol, · line 693

Quoted 4 lines

drivers/media/video/cx88/cx88-alsa.c +1 -1

 static struct snd_kcontrol_new snd_cx88_dac_switch = {
 	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
-	.name = "Playback Switch",
+	.name = "Audio Out Switch",

The name is a little better. But just to play devil's advocate, it still doesn't say exactly what it does: On/Off? Output 1/Output 2?

Quoted 7 lines

drivers/media/video/cx88/cx88-alsa.c +0 -0

 	.info = snd_ctl_boolean_mono_info,
 	.get = snd_cx88_switch_get,
 	.put = snd_cx88_switch_put,

@@ -668,7 +699,7 @@ static struct snd_kcontrol_new snd_cx88_dac_switch = {
 

drivers/media/video/cx88/cx88-alsa.c static struct snd_kcontrol_new snd_cx88_dac_switch = { · line 702

Quoted 4 lines

drivers/media/video/cx88/cx88-alsa.c +1 -1

 static struct snd_kcontrol_new snd_cx88_source_switch = {
 	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
-	.name = "Capture Switch",
+	.name = "Tuner Switch",

Ditto.

drivers/media/video/cx88/cx88-cards.c static const struct cx88_board cx88_boards[] = { · line 965

Quoted 13 lines

drivers/media/video/cx88/cx88-alsa.c +0 -0

 	.info = snd_ctl_boolean_mono_info,
 	.get = snd_cx88_switch_get,
 	.put = snd_cx88_switch_put,

drivers/media/video/cx88/cx88-cards.c +1 -1

index 2918a6e..c7ac0fe 100644
@@ -962,19 +962,26 @@ static const struct cx88_board cx88_boards[] = {
 	},
 	[CX88_BOARD_HAUPPAUGE_NOVASPLUS_S1] = {
 		.name		= "Hauppauge Nova-S-Plus DVB-S",
-		.tuner_type	= TUNER_ABSENT,
+		.tuner_type	= UNSET, /* BUG: Needed by cx88_i2c_init for WM8775 */

Hrmm. UNSET can cause many drivers to try to probe the I2C bus for a tuner (but I'm not sure if it has that effect in the cx88 driver). Probing on the I2C bus is generally bad and should be avoided, especially if you know for certain nothing is there.

Also I see that the .tuner_type check in cx88_i2c_init() is needed for kernels older than 2.6.26. This paticular change to UNSET shouldn't be done.

Quoted 49 lines

drivers/media/video/cx88/cx88-cards.c +7 -0

 		.radio_type	= UNSET,
 		.tuner_addr	= ADDR_UNSET,
 		.radio_addr	= ADDR_UNSET,
+        .audio_chip = V4L2_IDENT_WM8775,
 		.input		= {{
 			.type	= CX88_VMUX_DVB,
 			.vmux	= 0,
+            /* 2: Line-In */
+            .audioroute = 2,
 		},{
 			.type	= CX88_VMUX_COMPOSITE1,
 			.vmux	= 1,
+            /* 2: Line-In */
+            .audioroute = 2,
 		},{
 			.type	= CX88_VMUX_SVIDEO,
 			.vmux	= 2,
+            /* 2: Line-In */
+            .audioroute = 2,
 		}},
 		.mpeg           = CX88_MPEG_DVB,
 	},

drivers/media/video/cx88/cx88-video.c +19 -0

index 0fab65c..2c5bd14 100644
@@ -992,6 +992,32 @@ int cx88_set_control(struct cx88_core *core, struct v4l2_control *ctl)
 		ctl->value = c->v.minimum;
 	if (ctl->value > c->v.maximum)
 		ctl->value = c->v.maximum;
+
+	/* If a WM8775 is used for audio input utilise the audio controls */
+	if (core->board.audio_chip &&
+			core->board.audio_chip == V4L2_IDENT_WM8775) {
+		struct v4l2_control client_ctl;
+
+		client_ctl.id = ctl->id;
+		switch (ctl->id) {
+			case V4L2_CID_AUDIO_MUTE:
+				client_ctl.value = ctl->value;
+				break;
+			case V4L2_CID_AUDIO_VOLUME:
+				client_ctl.value = (ctl->value) ?
+					(0x90 + ctl->value) << 8 : 0;
+				break;
+			case V4L2_CID_AUDIO_BALANCE:
+				client_ctl.value = ctl->value << 9;
+				break;
+			default:

drivers/media/video/cx88/cx88-video.c int cx88_set_control(struct cx88_core *core, struct v4l2_control *ctl) · line 1019

Quoted 6 lines

drivers/media/video/cx88/cx88-video.c +6 -0

+				client_ctl.id = 0;
+				break;
+		}
+		if (client_ctl.id)
+			call_all(core, core, s_ctrl, &client_ctl);
+	}

My previous comment about calling subdevs applies here.

Quoted 31 lines

drivers/media/video/cx88/cx88-video.c +3 -1

 	mask=c->mask;
 	switch (ctl->id) {
 	case V4L2_CID_AUDIO_BALANCE:

@@ -1537,7 +1563,9 @@ static int radio_queryctrl (struct file *file, void *priv,
 	if (c->id <  V4L2_CID_BASE ||
 		c->id >= V4L2_CID_LASTP1)
 		return -EINVAL;
-	if (c->id == V4L2_CID_AUDIO_MUTE) {
+	if (c->id == V4L2_CID_AUDIO_MUTE ||
+		c->id == V4L2_CID_AUDIO_VOLUME ||
+			c->id == V4L2_CID_AUDIO_BALANCE) {
 		for (i = 0; i < CX8800_CTLS; i++) {
 			if (cx8800_ctls[i].v.id == c->id)
 				break;

drivers/media/video/wm8775.c +2 -0

index 5c2ba59..140e54a 100644
@@ -55,6 +55,8 @@ struct wm8775_state {
 	struct v4l2_subdev sd;
 	u8 input;		/* Last selected input (0-0xf) */
 	u8 muted;
+    u16 volume;
+    u16 balance;
 };
 
 static inline struct wm8775_state *to_state(struct v4l2_subdev *sd)

@@ -80,6 +82,27 @@ static int wm8775_write(struct v4l2_subdev *sd, int reg, u16 val)
 	return -1;
 }
 

drivers/media/video/wm8775.c static int wm8775_write(struct v4l2_subdev *sd, int reg, u16 val) · line 93

Quoted 9 lines

drivers/media/video/wm8775.c +9 -0

+static void wm8775_set_audio(struct v4l2_subdev *sd)
+{
+    struct wm8775_state *state = to_state(sd);
+
+    u8 vol_l, vol_r;
+
+    /* normalize ( 65535 to 0 -> 255 to 0 (+24dB to -103dB) ) */
+    vol_l = ((min(65536 - state->balance, 32768) * state->volume) / 32768) >> 8;
+    vol_r = ((min(state->balance, (u16)32768) * state->volume) / 32768) >> 8;

A >> 15 is probably less expensive than a / 32768.

drivers/media/video/wm8775.c static int wm8775_write(struct v4l2_subdev *sd, int reg, u16 val) · line 96

Quoted 2 lines

drivers/media/video/wm8775.c +2 -0

+    /* Mute */
+    wm8775_write(sd, R21, 0x0c0);

Why glitch the audio when changing the volume?

Setting the zero crossing detection in the left and right gain registers should cause the chip to change gains in such a way that artifacts won't be heard. You may have to muck with the zero crossing detection timeout enable in register R07 too. See page 22 of the publicly available WM8775 datasheet.

drivers/media/video/wm8775.c static int wm8775_write(struct v4l2_subdev *sd, int reg, u16 val) · line 99

Quoted 2 lines

drivers/media/video/wm8775.c +2 -0

+    wm8775_write(sd, R14, vol_l);
+    wm8775_write(sd, R15, vol_r);

This change discards the zero-crossing detection enable that was manually turned on in other places in this driver which you replaced with a call to this function.

Quoted 13 lines

drivers/media/video/wm8775.c +5 -1

+    /* Un-mute */
+    if (!state->muted)
+      wm8775_write(sd, R21, state->input);
+}
+
 static int wm8775_s_routing(struct v4l2_subdev *sd,
 			    u32 input, u32 output, u32 config)
 {

@@ -95,12 +118,7 @@ static int wm8775_s_routing(struct v4l2_subdev *sd,
 		return -EINVAL;
 	}
 	state->input = input;
-	if (state->muted)

drivers/media/video/wm8775.c static int wm8775_s_routing(struct v4l2_subdev *sd, · line 121

Quoted 6 lines

drivers/media/video/wm8775.c +1 -5

-		return 0;
-	wm8775_write(sd, R21, 0x0c0);
-	wm8775_write(sd, R14, 0x1d4);
-	wm8775_write(sd, R15, 0x1d4);
-	wm8775_write(sd, R21, 0x100 + state->input);
+        wm8775_set_audio(sd);

Zero crossing detection enable is discarded with this change.

Quoted 54 lines

drivers/media/video/wm8775.c +29 -11

 	return 0;
 }
 

@@ -108,9 +126,23 @@ static int wm8775_g_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl)
 {
 	struct wm8775_state *state = to_state(sd);
 
-	if (ctrl->id != V4L2_CID_AUDIO_MUTE)
-		return -EINVAL;
-	ctrl->value = state->muted;
+    switch (ctrl->id) {
+    case V4L2_CID_AUDIO_MUTE:
+        ctrl->value = state->muted;
+        break;
+
+    case V4L2_CID_AUDIO_VOLUME:
+        ctrl->value = state->volume;
+        break;
+
+    case V4L2_CID_AUDIO_BALANCE:
+        ctrl->value = state->balance;
+        break;
+
+    default:
+        return -EINVAL;
+    }
+
 	return 0;
 }
 

@@ -118,14 +150,24 @@ static int wm8775_s_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl)
 {
 	struct wm8775_state *state = to_state(sd);
 
-	if (ctrl->id != V4L2_CID_AUDIO_MUTE)
-		return -EINVAL;
-	state->muted = ctrl->value;
-	wm8775_write(sd, R21, 0x0c0);
-	wm8775_write(sd, R14, 0x1d4);
-	wm8775_write(sd, R15, 0x1d4);
-	if (!state->muted)
-		wm8775_write(sd, R21, 0x100 + state->input);
+    switch (ctrl->id) {
+    case V4L2_CID_AUDIO_MUTE:
+        state->muted = ctrl->value;
+        break;
+
+    case V4L2_CID_AUDIO_VOLUME:
+        state->volume = ctrl->value;
+        break;
+
+    case V4L2_CID_AUDIO_BALANCE:
+        state->balance = ctrl->value;
+        break;

drivers/media/video/wm8775.c static int wm8775_s_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl) · line 170

Quoted 6 lines

drivers/media/video/wm8775.c +6 -0

+
+    default:
+        return -EINVAL;
+    }
+    wm8775_set_audio(sd);
+

Zero crossing detection enable is discarded with this change.

Quoted 15 lines

drivers/media/video/wm8775.c +3 -2

 	return 0;
 }
 

@@ -140,31 +182,71 @@ static int wm8775_log_status(struct v4l2_subdev *sd)
 {
 	struct wm8775_state *state = to_state(sd);
 
-	v4l2_info(sd, "Input: %d%s\n", state->input,
-			state->muted ? " (muted)" : "");
+        v4l2_info(sd, "Volume: %04x%s Balance: %04x Input: %d\n",
+                state->volume, state->muted ? " (muted)" : "",
+                state->balance, state->input);
 	return 0;
 }
 

drivers/media/video/wm8775.c static int wm8775_log_status(struct v4l2_subdev *sd) · line 197

Quoted 13 lines

drivers/media/video/wm8775.c +1 -6

 static int wm8775_s_frequency(struct v4l2_subdev *sd, struct v4l2_frequency *freq)
 {
-	struct wm8775_state *state = to_state(sd);
-
 	/* If I remove this, then it can happen that I have no
 	   sound the first time I tune from static to a valid channel.
 	   It's difficult to reproduce and is almost certainly related
 	   to the zero cross detect circuit. */
-	wm8775_write(sd, R21, 0x0c0);
-	wm8775_write(sd, R14, 0x1d4);
-	wm8775_write(sd, R15, 0x1d4);
-	wm8775_write(sd, R21, 0x100 + state->input);
+        wm8775_set_audio(sd);

Zero crossing detection enable is discarded with this change. It also reverse the sense of the comment that remained unchanged.

Quoted 93 lines

drivers/media/video/wm8775.c +48 -27

 	return 0;
 }
 
+static struct v4l2_queryctrl wm8775_qctrl[] = {
+       {
+               .id            = V4L2_CID_AUDIO_VOLUME,
+               .name          = "Volume",
+               .minimum       = 0,
+               .maximum       = 65535,
+               .step          = 65535/100,
+               .default_value = 0xCF00, /* 0 dB */
+               .flags         = 0,
+               .type          = V4L2_CTRL_TYPE_INTEGER,
+       }, {
+               .id            = V4L2_CID_AUDIO_MUTE,
+               .name          = "Mute",
+               .minimum       = 0,
+               .maximum       = 1,
+               .step          = 1,
+               .default_value = 1,
+               .flags         = 0,
+               .type          = V4L2_CTRL_TYPE_BOOLEAN,
+       }, {
+               .id            = V4L2_CID_AUDIO_BALANCE,
+               .name          = "Balance",
+               .minimum       = 0,
+               .maximum       = 65535,
+               .step          = 65535/100,
+               .default_value = 32768,
+               .flags         = 0,
+               .type          = V4L2_CTRL_TYPE_INTEGER,
+       }
+};
+
+static int wm8775_query_ctrl(struct v4l2_subdev *sd, struct v4l2_queryctrl *qc)
+{
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(wm8775_qctrl); i++)
+        if (qc->id && qc->id == wm8775_qctrl[i].id) {
+            memcpy(qc, &wm8775_qctrl[i], sizeof(*qc));
+            return 0;
+        }
+    return -EINVAL;
+}
+
 /* ----------------------------------------------------------------------- */
 
 static const struct v4l2_subdev_core_ops wm8775_core_ops = {
 	.log_status = wm8775_log_status,
 	.g_chip_ident = wm8775_g_chip_ident,
+        .queryctrl = wm8775_query_ctrl,
 	.g_ctrl = wm8775_g_ctrl,
 	.s_ctrl = wm8775_s_ctrl,
 };

@@ -212,36 +294,23 @@ static int wm8775_probe(struct i2c_client *client,
 	v4l2_i2c_subdev_init(sd, client, &wm8775_ops);
 	state->input = 2;
 	state->muted = 0;
+    state->volume = 0xCF00;
+    state->balance = 0x8000;
 
 	/* Initialize wm8775 */
 
-	/* RESET */
-	wm8775_write(sd, R23, 0x000);
-	/* Disable zero cross detect timeout */
-	wm8775_write(sd, R7, 0x000);
-	/* Left justified, 24-bit mode */
-	wm8775_write(sd, R11, 0x021);
-	/* Master mode, clock ratio 256fs */
-	wm8775_write(sd, R12, 0x102);
-	/* Powered up */
-	wm8775_write(sd, R13, 0x000);
-	/* ADC gain +2.5dB, enable zero cross */
-	wm8775_write(sd, R14, 0x1d4);
-	/* ADC gain +2.5dB, enable zero cross */
-	wm8775_write(sd, R15, 0x1d4);
-	/* ALC Stereo, ALC target level -1dB FS max gain +8dB */
-	wm8775_write(sd, R16, 0x1bf);
-	/* Enable gain control, use zero cross detection,
-	   ALC hold time 42.6 ms */
-	wm8775_write(sd, R17, 0x185);
-	/* ALC gain ramp up delay 34 s, ALC gain ramp down delay 33 ms */
-	wm8775_write(sd, R18, 0x0a2);
-	/* Enable noise gate, threshold -72dBfs */
-	wm8775_write(sd, R19, 0x005);
-	/* Transient window 4ms, lower PGA gain limit -1dB */
-	wm8775_write(sd, R20, 0x07a);
-	/* LRBOTH = 1, use input 2. */
-	wm8775_write(sd, R21, 0x102);
+    wm8775_write(sd, R23, 0x000); /* RESET */
+    wm8775_write(sd, R11, 0x022); /* HPF enable, I2S mode, 24-bit */

drivers/media/video/wm8775.c static int wm8775_probe(struct i2c_client *client, · line 313

Quoted 10 lines

drivers/media/video/wm8775.c +10 -0

+    wm8775_write(sd, R12, 0x102); /* Master mode, clock ratio 256fs */
+    wm8775_write(sd, R13, 0x000); /* Powered up */
+    wm8775_set_audio(sd);         /* set volume/mute */
+#if 0 /* Enable ALC */
+    wm8775_write(sd, R16, 0x1bb); /* ALC stereo, ALC target level -5dB FS, ALC max gain +8dB */
+    wm8775_write(sd, R17, 0x185); /* Enable LC, use zero cross, ALC hold 42.7 ms */
+    wm8775_write(sd, R18, 0x0a2); /* ALC decay time 34 s, ALC attack time 33 ms */
+    wm8775_write(sd, R19, 0x005); /* Enable noise gate, threshold -72dB fs */
+    wm8775_write(sd, R20, 0x0fb); /* Transient window 4ms, ALC min gain -5dB */
+#endif

I haven't inspected this thoroughly because you combined a whitespace/comment placement change with a functional change, so the functions changes are not obvious.

These sort of changes should be done in two patches, one for the functional change and one for the fluff.

I can say that disabling the ALC is not what the ivtv driver is expecting. Automatic control to avoid clipping is taken for granted. Turning ALC off may cause users problems they never had before.

ivtv/PVR-150 users only get *1* volume control in the current v4l2_ctrl framework, and that is volume control in the CX25843. They have no control currently of the WM8775, and if it starts clipping the input, they have no way to correct it. (Not that the normal user might even know where to begin.)

So NAK on turning off the ALC by default.

Just for fun, I dug up some ASCII art of a similar ivtv card discussed on the ivtv-devel list in July 2009. The issue was better auio performance could be obtained by having manual control over the WM8739 and then the CX25841, but V4L2 only really allowed 1 user volume control.

              +----------+                                       +---------------+
              |     Sel0 |<--------------------------------------| GPIO14        |
              |     Sel1 |<--------------------------------------| GPIO15        |
              |          |                                       |               |
(FM AF L)---->| 74HC4052 |                                       |               |
(FM AF R)---->|          |         +----------------+------------|I2C Data & CLK |
              | Dual 4:1 |         V                V            |               |
              | Mux      |     +------+      +--------------+    |               |
Line-in L --->|          |     |WM8739|      |   CX25841    |    |   CX23416     |

Line-in R --->|          |---->|Analog|----->|I2S Data In   |    |               |
              |          |---->|to I2S|------|I2S Clock     |    |               |
White Conn?-->|          |     |Audio |      | I2S Data Out |--->|I2S Data In    |
              |          |     +------+      | I2S Clock    |----|I2S Clock      |
              +----------+                   |              |    |               |
Tuner SIF ---------------------------------->|SIF In        |    +---------------+
                                             |              |
                                             +--------------+