Gitweb: http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=f8f629...
Commit: f8f6296adad30cadd65555dfde489d1080b2001c
Parent: fff4205f1d64163132609942314e94ec3ba2ed6b
Author: Andy Walls <awalls@radix.net>
AuthorDate: Wed Jul 23 20:28:23 2008 -0300
Committer: Mauro Carvalho Chehab <mchehab@infradead.org>
CommitDate: Sat Jul 26 12:54:18 2008 -0300
V4L/DVB (8461): cx18: Fix 32 kHz audio sample output rate for analog tuner SIF input
cx18: Fix 32 kHz audio sample output rate for analog tuner SIF input so it
works. The AUX_PLL VCO was being operated at 196.6 MHz out of the spec'ed
200-600 MHz range. Fixed the multipler and post dividers to operate the VCO
within specification and added comments on how magic numbers are derived.
Thanks to Hans Verkuil for pointing out this interesting problem to solve.
Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
---
drivers/media/video/cx18/cx18-av-audio.c | 41 +++++++++++++++++++++--------
1 files changed, 29 insertions(+), 12 deletions(-)
diff --git a/drivers/media/video/cx18/cx18-av-audio.c b/drivers/media/video/cx18/cx18-av-audio.c
index c40a286..7245d37 100644
--- a/drivers/media/video/cx18/cx18-av-audio.c
+++ b/drivers/media/video/cx18/cx18-av-audio.c
@@ -30,7 +30,6 @@ static int set_audclk_freq(struct cx18 *cx, u32 freq)
if (freq != 32000 && freq != 44100 && freq != 48000)
return -EINVAL;
- /* common for all inputs and rates */
/* SA_MCLK_SEL=1, SA_MCLK_DIV=0x10 */
cx18_av_write(cx, 0x127, 0x50);
@@ -38,15 +37,20 @@ static int set_audclk_freq(struct cx18 *cx, u32 freq)
switch (freq) {
case 32000:
/* VID_PLL and AUX_PLL */
- cx18_av_write4(cx, 0x108, 0x1006040f);
+ cx18_av_write4(cx, 0x108, 0x1408040f);
/* AUX_PLL_FRAC */
- cx18_av_write4(cx, 0x110, 0x01bb39ee);
+ /* 0x8.9504318a * 28,636,363.636 / 0x14 = 32000 * 384 */
+ cx18_av_write4(cx, 0x110, 0x012a0863);
- /* src3/4/6_ctl = 0x0801f77f */
+ /* src3/4/6_ctl */
+ /* 0x1.f77f = (4 * 15734.26) / 32000 */
cx18_av_write4(cx, 0x900, 0x0801f77f);
cx18_av_write4(cx, 0x904, 0x0801f77f);
cx18_av_write4(cx, 0x90c, 0x0801f77f);
+
+ /* SA_MCLK_SEL=1, SA_MCLK_DIV=0x14 */
+ cx18_av_write(cx, 0x127, 0x54);
break;
case 44100:
@@ -54,9 +58,11 @@ static int set_audclk_freq(struct cx18 *cx, u32 freq)
cx18_av_write4(cx, 0x108, 0x1009040f);
/* AUX_PLL_FRAC */
+ /* 0x9.7635eb * 28,636,363 / 0x10 = 44100 * 384 */
cx18_av_write4(cx, 0x110, 0x00ec6bd6);
- /* src3/4/6_ctl = 0x08016d59 */
+ /* src3/4/6_ctl */
+ /* 0x1.6d59 = (4 * 15734.26) / 44100 */
cx18_av_write4(cx, 0x900, 0x08016d59);
cx18_av_write4(cx, 0x904, 0x08016d59);
cx18_av_write4(cx, 0x90c, 0x08016d59);
@@ -67,9 +73,11 @@ static int set_audclk_freq(struct cx18 *cx, u32 freq)
cx18_av_write4(cx, 0x108, 0x100a040f);
/* AUX_PLL_FRAC */
+ /* 0xa.4c6b728 * 28,636,363 / 0x10 = 48000 * 384 */
cx18_av_write4(cx, 0x110, 0x0098d6e5);
- /* src3/4/6_ctl = 0x08014faa */
+ /* src3/4/6_ctl */
+ /* 0x1.4faa = (4 * 15734.26) / 48000 */
cx18_av_write4(cx, 0x900, 0x08014faa);
cx18_av_write4(cx, 0x904, 0x08014faa);
cx18_av_write4(cx, 0x90c, 0x08014faa);
@@ -82,12 +90,15 @@ static int set_audclk_freq(struct cx18 *cx, u32 freq)
cx18_av_write4(cx, 0x108, 0x1e08040f);
/* AUX_PLL_FRAC */
+ /* 0x8.9504348 * 28,636,363 / 0x1e = 32000 * 256 */
cx18_av_write4(cx, 0x110, 0x012a0869);
- /* src1_ctl = 0x08010000 */
+ /* src1_ctl */
+ /* 0x1.0000 = 32000/32000 */
cx18_av_write4(cx, 0x8f8, 0x08010000);
- /* src3/4/6_ctl = 0x08020000 */
+ /* src3/4/6_ctl */
+ /* 0x2.0000 = 2 * (32000/32000) */
cx18_av_write4(cx, 0x900, 0x08020000);
cx18_av_write4(cx, 0x904, 0x08020000);
cx18_av_write4(cx, 0x90c, 0x08020000);
@@ -101,12 +112,15 @@ static int set_audclk_freq(struct cx18 *cx, u32 freq)
cx18_av_write4(cx, 0x108, 0x1809040f);
/* AUX_PLL_FRAC */
+ /* 0x9.76346B * 28,636,363 / 0x18 = 44100 * 256 */
cx18_av_write4(cx, 0x110, 0x00ec6bd6);
- /* src1_ctl = 0x08010000 */
+ /* src1_ctl */
+ /* 0x1.60cd = 44100/32000 */
cx18_av_write4(cx, 0x8f8, 0x080160cd);
- /* src3/4/6_ctl = 0x08020000 */
+ /* src3/4/6_ctl */
+ /* 0x1.7385 = 2 * (32000/44100) */
cx18_av_write4(cx, 0x900, 0x08017385);
cx18_av_write4(cx, 0x904, 0x08017385);
cx18_av_write4(cx, 0x90c, 0x08017385);
@@ -117,12 +131,15 @@ static int set_audclk_freq(struct cx18 *cx, u32 freq)
cx18_av_write4(cx, 0x108, 0x180a040f);
/* AUX_PLL_FRAC */
+ /* 0xa.4c6b728 * 28,636,363 / 0x18 = 48000 * 256 */
cx18_av_write4(cx, 0x110, 0x0098d6e5);
- /* src1_ctl = 0x08010000 */
+ /* src1_ctl */
+ /* 0x1.8000 = 48000/32000 */
cx18_av_write4(cx, 0x8f8, 0x08018000);
- /* src3/4/6_ctl = 0x08020000 */
+ /* src3/4/6_ctl */
+ /* 0x1.5555 = 2 * (32000/48000) */
cx18_av_write4(cx, 0x900, 0x08015555);
cx18_av_write4(cx, 0x904, 0x08015555);
cx18_av_write4(cx, 0x90c, 0x08015555);
--
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