V4L/DVB (11624): cx18: Toggle the AI1 mux when changing the CX18_AUDIO_ENABLE register

Toggle the AI1 mux when changing the CX18_AUDIO_ENABLE register.  It's hard to
reliably tell when we have written to this register successfully unless we
change some bits we know we can read back.  The AI mux bits always read back
what we wrote to them, so force them to toggle whenever we have to write to
the register, so we can tell we wrote to the register successfully.

This change was prompted by users experiencing broadcast audio decoding
problems after the cx18 module loads for the first time.

Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 38 insertions, 6 deletions

diff --git a/drivers/media/video/cx18/cx18-audio.c b/drivers/media/video/cx18/cx18-audio.c
index 7a8ad5963de..35268923911 100644
--- a/drivers/media/video/cx18/cx18-audio.c
+++ b/drivers/media/video/cx18/cx18-audio.c
@@ -26,14 +26,18 @@
 #include "cx18-cards.h"
 #include "cx18-audio.h"
 
-#define CX18_AUDIO_ENABLE 0xc72014
+#define CX18_AUDIO_ENABLE    0xc72014
+#define CX18_AI1_MUX_MASK    0x30
+#define CX18_AI1_MUX_I2S1    0x00
+#define CX18_AI1_MUX_I2S2    0x10
+#define CX18_AI1_MUX_843_I2S 0x20
 
 /* Selects the audio input and output according to the current
    settings. */
 int cx18_audio_set_io(struct cx18 *cx)
 {
 	const struct cx18_card_audio_input *in;
-	u32 val;
+	u32 u, v;
 	int err;
 
 	/* Determine which input to use */
@@ -52,9 +56,37 @@ int cx18_audio_set_io(struct cx18 *cx)
 		return err;
 
 	/* FIXME - this internal mux should be abstracted to a subdev */
-	val = cx18_read_reg(cx, CX18_AUDIO_ENABLE) & ~0x30;
-	val |= (in->audio_input > CX18_AV_AUDIO_SERIAL2) ? 0x20 :
-					(in->audio_input << 4);
-	cx18_write_reg_expect(cx, val | 0xb00, CX18_AUDIO_ENABLE, val, 0x30);
+	u = cx18_read_reg(cx, CX18_AUDIO_ENABLE);
+	v = u & ~CX18_AI1_MUX_MASK;
+	switch (in->audio_input) {
+	case CX18_AV_AUDIO_SERIAL1:
+		v |= CX18_AI1_MUX_I2S1;
+		break;
+	case CX18_AV_AUDIO_SERIAL2:
+		v |= CX18_AI1_MUX_I2S2;
+		break;
+	default:
+		v |= CX18_AI1_MUX_843_I2S;
+		break;
+	}
+	if (v == u) {
+		/* force a toggle of some AI1 MUX control bits */
+		u &= ~CX18_AI1_MUX_MASK;
+		switch (in->audio_input) {
+		case CX18_AV_AUDIO_SERIAL1:
+			u |= CX18_AI1_MUX_843_I2S;
+			break;
+		case CX18_AV_AUDIO_SERIAL2:
+			u |= CX18_AI1_MUX_843_I2S;
+			break;
+		default:
+			u |= CX18_AI1_MUX_I2S1;
+			break;
+		}
+		cx18_write_reg_expect(cx, u | 0xb00, CX18_AUDIO_ENABLE,
+				      u, CX18_AI1_MUX_MASK);
+	}
+	cx18_write_reg_expect(cx, v | 0xb00, CX18_AUDIO_ENABLE,
+			      v, CX18_AI1_MUX_MASK);
 	return 0;
 }