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Samsung YHxxx: reduce pop noise on power down

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Change-Id: Ifc82ac1051ed05527393838d8aa93bde65287b5d
This commit is contained in:
Sebastian Leonhardt 2015-09-10 23:57:25 +02:00 • committed by Gerrit Rockbox
parent 1cada1f833
commit 399904a916
1 changed files with 6 additions and 1 deletions
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7
firmware/drivers/audio/ak4537.c
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@ -176,6 +176,12 @@ void audiohw_close(void)
/* power down the DAC */ /* power down the DAC */
akc_clear(AK4537_PM2, PMDAC); 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 */ /* power down the headphone amp */
akc_set(AK4537_SIGSEL2, HPL | HPR); akc_set(AK4537_SIGSEL2, HPL | HPR);
@ -187,7 +193,6 @@ void audiohw_close(void)
/* power down VCOM */ /* power down VCOM */
akc_clear(AK4537_PM1, PMVCM); akc_clear(AK4537_PM1, PMVCM);
udelay(100000);
akcodec_close(); /* target-specific */ akcodec_close(); /* target-specific */
} }