staging/easycap: Add option to set the hardware audio gain

A new module parameter adjusts the gain of the AC'97 audio chip, if
one is present.  Attenuation as well as amplification should be possible
according to the datasheet, but attenuation seems not to work yet.

Signed-off-by: Mike Thomas <rmthomas@sciolus.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/easycap/easycap_debug.h

@@ -25,3 +25,4 @@
 */
 /*****************************************************************************/
 extern int debug;
+extern int gain;

drivers/staging/easycap/easycap_ioctl.c

@@ -873,18 +873,26 @@ i1 = 0;
 while (0xFFFFFFFF != easycap_control[i1].id) {
 	if (V4L2_CID_AUDIO_VOLUME == easycap_control[i1].id) {
 		if ((easycap_control[i1].minimum > value) || \
-			(easycap_control[i1].maximum < value))
+				(easycap_control[i1].maximum < value))
 			value = easycap_control[i1].default_value;
+		if ((easycap_control[i1].minimum <= peasycap->volume) && \
+					(easycap_control[i1].maximum >= \
+							peasycap->volume)) {
+			if (peasycap->volume == value) {
+				SAM("unchanged volume at  0x%02X\n", value);
+				return 0;
+			}
+		}
 		peasycap->volume = value;
 		mood = (16 > peasycap->volume) ? 16 : \
 			((31 < peasycap->volume) ? 31 : \
 			(__s8) peasycap->volume);
 		if (!audio_gainset(peasycap->pusb_device, mood)) {
-			SAM("adjusting volume to 0x%01X\n", mood);
+			SAM("adjusting volume to 0x%02X\n", mood);
 			return 0;
 		} else {
 			SAM("WARNING: failed to adjust volume to " \
-							"0x%1X\n", mood);
+							"0x%2X\n", mood);
 			return -ENOENT;
 		}
 		break;

drivers/staging/easycap/easycap_low.c

@@ -988,9 +988,9 @@ if (NULL == peasycap)
 
 pusb_device = peasycap->pusb_device;
 if (NULL == pusb_device)
-	return -EFAULT;
+	return -ENODEV;
 
-JOT(8, "%02X %02X %02X %02X %02X %02X %02X %02X\n",	\
+JOM(8, "%02X %02X %02X %02X %02X %02X %02X %02X\n",	\
 			requesttype, request,		\
 			(0x00FF & value_unmute),	\
 			(0xFF00 & value_unmute) >> 8,	\
@@ -1029,41 +1029,25 @@ if (rc != (int)length)
  *                    THE UPPER BYTE SEEMS TO HAVE NO EFFECT.
  */
 /*--------------------------------------------------------------------------*/
-
 SET(pusb_device, 0x0500, 0x0094);
-
 SET(pusb_device, 0x0500, 0x008C);
-
 SET(pusb_device, 0x0506, 0x0001);
 SET(pusb_device, 0x0507, 0x0000);
-
 id1 = read_vt(pusb_device, 0x007C);
 id2 = read_vt(pusb_device, 0x007E);
-SAY("0x%04X:0x%04X is audio vendor id\n", id1, id2);
-
+SAM("0x%04X:0x%04X is audio vendor id\n", id1, id2);
 /*---------------------------------------------------------------------------*/
 /*
-*   SELECT AUDIO SOURCE "LINE IN" AND SET DEFAULT GAIN TO 0 dB.
-*
-*   THESE COMMANDS SEEM TO BE ACCEPTED (THOUGH POSSIBLY IGNORED) EVEN WHEN
-*   THERE IS NO SEPARATE AUDIO CHIP PRESENT.
+ *  SELECT AUDIO SOURCE "LINE IN" AND SET THE AUDIO GAIN.
 */
 /*---------------------------------------------------------------------------*/
-
-write_vt(pusb_device, 0x0002, 0x8000);
-write_vt(pusb_device, 0x001C, 0x8000);
-
-write_vt(pusb_device, 0x000E, 0x0000);
-write_vt(pusb_device, 0x0010, 0x0000);
-write_vt(pusb_device, 0x0012, 0x8000);
-write_vt(pusb_device, 0x0016, 0x0000);
-
-write_vt(pusb_device, 0x001A, 0x0404);
-write_vt(pusb_device, 0x0002, 0x0000);
-write_vt(pusb_device, 0x001C, 0x0000);
-
+if (31 < gain)
+	gain = 31;
+if (0 > gain)
+	gain = 0;
+if (0 != audio_gainset(pusb_device, (__s8)gain))
+	SAY("ERROR: audio_gainset() failed\n");
 check_vt(pusb_device);
-
 return 0;
 }
 /*****************************************************************************/
@@ -1096,17 +1080,23 @@ if (0 > igot)
 if (0x8000 & igot)
 	SAY("register 0x%02X muted\n", 0x12);
 
+igot = read_vt(pusb_device, 0x0014);
+if (0 > igot)
+	SAY("ERROR: failed to read VT1612A register 0x14\n");
+if (0x8000 & igot)
+	SAY("register 0x%02X muted\n", 0x14);
+
 igot = read_vt(pusb_device, 0x0016);
 if (0 > igot)
 	SAY("ERROR: failed to read VT1612A register 0x16\n");
 if (0x8000 & igot)
 	SAY("register 0x%02X muted\n", 0x16);
 
-igot = read_vt(pusb_device, 0x001A);
+igot = read_vt(pusb_device, 0x0018);
 if (0 > igot)
-	SAY("ERROR: failed to read VT1612A register 0x1A\n");
+	SAY("ERROR: failed to read VT1612A register 0x18\n");
 if (0x8000 & igot)
-	SAY("register 0x%02X muted\n", 0x1A);
+	SAY("register 0x%02X muted\n", 0x18);
 
 igot = read_vt(pusb_device, 0x001C);
 if (0 > igot)
@@ -1118,14 +1108,18 @@ return 0;
 }
 /*****************************************************************************/
 /*---------------------------------------------------------------------------*/
-/*
- *  NOTE:  THIS DOES INCREASE THE VOLUME DRAMATICALLY:
- *         audio_gainset(pusb_device, 0x000F);
+/*  NOTE:  THIS DOES INCREASE THE VOLUME DRAMATICALLY:
+ *                      audio_gainset(pusb_device, 0x000F);
  *
- *  IF 16<loud<31 VT1621A REGISTER 0x1C IS SET FOR POSITIVE GAIN.
- *  IF loud<=16 VT1621A REGISTER 0x1C IS SET FOR ZERO GAIN.
- *  THERE IS NEVER ANY (ADDITIONAL) ATTENUATION.
- */
+ *       loud        dB  register 0x10      dB register 0x1C    dB total
+ *         0               -34.5                   0             -34.5
+ *        ..                ....                   .              ....
+ *        15                10.5                   0              10.5
+ *        16                12.0                   0              12.0
+ *        17                12.0                   1.5            13.5
+ *        ..                ....                  ....            ....
+ *        31                12.0                  22.5            34.5
+*/
 /*---------------------------------------------------------------------------*/
 int
 audio_gainset(struct usb_device *pusb_device, __s8 loud)
@@ -1134,25 +1128,65 @@ int igot;
 __u8 u8;
 __u16 mute;
 
-if (16 > loud)
-	loud = 16;
-u8 = 0x000F & (__u8)(loud - 16);
+if ((struct usb_device *)NULL == pusb_device)
+	return -ENODEV;
+if (0 > loud)
+	loud = 0;
+if (31 < loud)
+	loud = 31;
 
 write_vt(pusb_device, 0x0002, 0x8000);
+/*---------------------------------------------------------------------------*/
+igot = read_vt(pusb_device, 0x000E);
+if (0 > igot) {
+	SAY("ERROR: failed to read VT1612A register 0x0E\n");
+	mute = 0x0000;
+} else
+	mute = 0x8000 & ((unsigned int)igot);
+mute = 0;
 
+if (16 > loud)
+	u8 = 0x01 | (0x001F & (((__u8)(15 - loud)) << 1));
+else
+	u8 = 0;
+
+JOT(8, "0x%04X=(mute|u8) for VT1612A register 0x0E\n", mute | u8);
+write_vt(pusb_device, 0x000E, (mute | u8));
+/*---------------------------------------------------------------------------*/
+igot = read_vt(pusb_device, 0x0010);
+if (0 > igot) {
+	SAY("ERROR: failed to read VT1612A register 0x10\n");
+	mute = 0x0000;
+} else
+	mute = 0x8000 & ((unsigned int)igot);
+mute = 0;
+
+JOT(8, "0x%04X=(mute|u8|(u8<<8)) for VT1612A register 0x10,...0x18\n", \
+							mute | u8 | (u8 << 8));
+write_vt(pusb_device, 0x0010, (mute | u8 | (u8 << 8)));
+write_vt(pusb_device, 0x0012, (mute | u8 | (u8 << 8)));
+write_vt(pusb_device, 0x0014, (mute | u8 | (u8 << 8)));
+write_vt(pusb_device, 0x0016, (mute | u8 | (u8 << 8)));
+write_vt(pusb_device, 0x0018, (mute | u8 | (u8 << 8)));
+/*---------------------------------------------------------------------------*/
 igot = read_vt(pusb_device, 0x001C);
 if (0 > igot) {
 	SAY("ERROR: failed to read VT1612A register 0x1C\n");
 	mute = 0x0000;
 } else
 	mute = 0x8000 & ((unsigned int)igot);
+mute = 0;
 
-JOT(8, "0x%04X=(mute|u8|(u8<<8))\n", mute | u8 | (u8 << 8));
+if (16 <= loud)
+	u8 = 0x000F & (__u8)(loud - 16);
+else
+	u8 = 0;
 
-write_vt(pusb_device, 0x001C, 0x8000);
+JOT(8, "0x%04X=(mute|u8|(u8<<8)) for VT1612A register 0x1C\n", \
+							mute | u8 | (u8 << 8));
 write_vt(pusb_device, 0x001C, (mute | u8 | (u8 << 8)));
+write_vt(pusb_device, 0x001A, 0x0404);
 write_vt(pusb_device, 0x0002, 0x0000);
-
 return 0;
 }
 /*****************************************************************************/
@@ -1161,6 +1195,8 @@ audio_gainget(struct usb_device *pusb_device)
 {
 int igot;
 
+if (NULL == pusb_device)
+	return -ENODEV;
 igot = read_vt(pusb_device, 0x001C);
 if (0 > igot)
 	SAY("ERROR: failed to read VT1612A register 0x1C\n");

drivers/staging/easycap/easycap_main.c

@@ -34,8 +34,10 @@
 
 int debug;
 int bars;
+int gain = 16;
 module_param(debug, int, S_IRUGO | S_IWUSR);
 module_param(bars, int, S_IRUGO | S_IWUSR);
+module_param(gain, int, S_IRUGO | S_IWUSR);
 
 /*---------------------------------------------------------------------------*/
 /*
@@ -4770,7 +4772,8 @@ easycap_module_init(void)
 int result;
 
 SAY("========easycap=======\n");
-JOT(4, "begins.  %i=debug %i=bars\n", debug, bars);
+JOT(4, "begins.  %i=debug %i=bars %i=gain\n", debug, bars, \
+						gain);
 SAY("version: " EASYCAP_DRIVER_VERSION "\n");
 /*---------------------------------------------------------------------------*/
 /*
@@ -4811,8 +4814,9 @@ MODULE_AUTHOR("R.M. Thomas <rmthomas@sciolus.org>");
 MODULE_DESCRIPTION(EASYCAP_DRIVER_DESCRIPTION);
 MODULE_VERSION(EASYCAP_DRIVER_VERSION);
 #if defined(EASYCAP_DEBUG)
-MODULE_PARM_DESC(debug, "Debug level: 0 (default),1,2,...,9");
+MODULE_PARM_DESC(debug, "Debug level: 0 (default),1,2,...");
 #endif /*EASYCAP_DEBUG*/
 MODULE_PARM_DESC(bars, \
 	"Testcard bars on input signal failure: 0=>no, 1=>yes(default)");
+MODULE_PARM_DESC(gain, "Audio gain: 0,...,16(default),...31");
 /*****************************************************************************/