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authorSebastian Leonhardt <sebastian.leonhardt@web.de>2015-09-10 23:57:25 +0200
committerGerrit Rockbox <gerrit@rockbox.org>2015-09-24 23:06:18 +0200
commit399904a916f3b17d2d6ee5817d5f1a53ffe62d30 (patch)
tree4a633aed295148f68bf665c281cba8f219e8f0c5
parent1cada1f8339d6b5f8506277f80e62aaef77ab774 (diff)
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Samsung YHxxx: reduce pop noise on power down
Change-Id: Ifc82ac1051ed05527393838d8aa93bde65287b5d
-rw-r--r--firmware/drivers/audio/ak4537.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/firmware/drivers/audio/ak4537.c b/firmware/drivers/audio/ak4537.c
index 67ce9e3ed9..3a014f7527 100644
--- a/firmware/drivers/audio/ak4537.c
+++ b/firmware/drivers/audio/ak4537.c
@@ -176,6 +176,12 @@ void audiohw_close(void)
/* power down the DAC */
akc_clear(AK4537_PM2, PMDAC);
+ /* Let the common voltage fall down before powering down headphone amp,
+ or a pop noise will occur. The fall time depends on the capacitor value
+ connected with the MUTET pin and is 100k*C up to 250k*C.
+ For Samsung YH devices (4.7uF) a minimum time of 470ms is needed. */
+ udelay(800000);
+
/* power down the headphone amp */
akc_set(AK4537_SIGSEL2, HPL | HPR);
@@ -187,7 +193,6 @@ void audiohw_close(void)
/* power down VCOM */
akc_clear(AK4537_PM1, PMVCM);
- udelay(100000);
akcodec_close(); /* target-specific */
}