V4L/DVB (7163): em28xx: makes audio settings more stable

Improves audio configurations on em28xx:
        - mutes audio before changing amux;
        - adds a delay after setting audio src;
        - waits up to 50ms for ac97 busy.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

2 files changed, 21 insertions, 10 deletions

diff --git a/drivers/media/video/em28xx/em28xx-core.c b/drivers/media/video/em28xx/em28xx-core.c
index 6965bafe54a1..275f1e936304 100644
--- a/drivers/media/video/em28xx/em28xx-core.c
+++ b/drivers/media/video/em28xx/em28xx-core.c
@@ -255,21 +255,26 @@ static int em28xx_write_reg_bits(struct em28xx *dev, u16 reg, u8 val,
  */
 static int em28xx_write_ac97(struct em28xx *dev, u8 reg, u8 *val)
 {
-        int ret;
+        int ret, i;
         u8 addr = reg & 0x7f;
         if ((ret = em28xx_write_regs(dev, AC97LSB_REG, val, 2)) < 0)
                 return ret;
         if ((ret = em28xx_write_regs(dev, AC97ADDR_REG, &addr, 1)) < 0)
                 return ret;
-        if ((ret = em28xx_read_reg(dev, AC97BUSY_REG)) < 0)
-                return ret;
-        else if (((u8) ret) & 0x01) {
-                em28xx_warn ("AC97 command still being executed: not handled properly!\n");
+
+        /* Wait up to 50 ms for AC97 command to complete */
+        for (i = 0; i < 10; i++) {
+                if ((ret = em28xx_read_reg(dev, AC97BUSY_REG)) < 0)
+                        return ret;
+                if (!((u8) ret) & 0x01)
+                        return 0;
+                msleep(5);
         }
+        em28xx_warn ("AC97 command still being executed: not handled properly!\n");
         return 0;
 }
 
-int em28xx_set_audio_source(struct em28xx *dev)
+static int em28xx_set_audio_source(struct em28xx *dev)
 {
         static char *enable  = "\x08\x08";
         static char *disable = "\x08\x88";
@@ -312,6 +317,7 @@ int em28xx_set_audio_source(struct em28xx *dev)
         ret = em28xx_write_reg_bits(dev, AUDIOSRC_REG, input, 0xc0);
         if (ret < 0)
                 return ret;
+        msleep(5);
 
         /* Sets AC97 mixer registers
            This is seems to be needed, even for non-ac97 configs
@@ -334,9 +340,10 @@ int em28xx_audio_analog_set(struct em28xx *dev)
         s[0] |= 0x1f - dev->volume;
         s[1] |= 0x1f - dev->volume;
 
-        if (dev->mute)
-                s[1] |= 0x80;
+        /* Mute */
+        s[1] |= 0x80;
         ret = em28xx_write_ac97(dev, MASTER_AC97, s);
+
         if (ret < 0)
                 return ret;
 
@@ -354,6 +361,11 @@ int em28xx_audio_analog_set(struct em28xx *dev)
         /* Selects the proper audio input */
         ret = em28xx_set_audio_source(dev);
 
+        /* Unmute device */
+        if (!dev->mute)
+                s[1] &= ~0x80;
+        ret = em28xx_write_ac97(dev, MASTER_AC97, s);
+
         return ret;
 }
 EXPORT_SYMBOL_GPL(em28xx_audio_analog_set);
diff --git a/drivers/media/video/em28xx/em28xx-video.c b/drivers/media/video/em28xx/em28xx-video.c
index f69f591eeaf6..eeda3b2faec8 100644
--- a/drivers/media/video/em28xx/em28xx-video.c
+++ b/drivers/media/video/em28xx/em28xx-video.c
@@ -189,7 +189,7 @@ static void video_mux(struct em28xx *dev, int index)
                 em28xx_i2c_call_clients(dev, VIDIOC_INT_S_AUDIO_ROUTING, &route);
         }
 
-        em28xx_set_audio_source(dev);
+        em28xx_audio_analog_set(dev);
 }
 
 /* Usage lock check functions */
@@ -837,7 +837,6 @@ static int em28xx_reg_len(int reg)
         case AC97LSB_REG:
         case HSCALELOW_REG:
         case VSCALELOW_REG:
-
                 return 2;
         default:
                 return 1;