diff options
| author | Michael Sparmann <theseven@rockbox.org> | 2010-11-13 11:38:38 +0000 |
|---|---|---|
| committer | Michael Sparmann <theseven@rockbox.org> | 2010-11-13 11:38:38 +0000 |
| commit | e872e9b91304262717218f93fd31f417d557588b (patch) | |
| tree | f1ce1da0471a31c1f1f946cbc14701f3b23f2739 /firmware/drivers | |
| parent | 2089a7dd7ba6a59f9b35adf2402689fc88b21d23 (diff) | |
iPod Nano 2G: Reduce popping noise during codec powerup, especially when driving high-impedance loads
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@28572 a1c6a512-1295-4272-9138-f99709370657
Diffstat (limited to 'firmware/drivers')
| -rw-r--r-- | firmware/drivers/audio/wm8975.c | 41 |
1 files changed, 40 insertions, 1 deletions
diff --git a/firmware/drivers/audio/wm8975.c b/firmware/drivers/audio/wm8975.c index 1def644f33..77d567d6da 100644 --- a/firmware/drivers/audio/wm8975.c +++ b/firmware/drivers/audio/wm8975.c @@ -53,7 +53,15 @@ static unsigned short wm8975_regs[] = [LINVOL] = LINVOL_LZCEN | 23, /* 0dB */ [RINVOL] = RINVOL_RIVU | RINVOL_RZCEN | 23, /* 0dB */ [DAPCTRL] = DAPCTRL_DACMU, +/* This reduces the popping noise during codec powerup + noticably, especially with high-impedance loads. + We might want to change this for all targets, + but it has only been tested on iPod Nano 2G so far. */ +#ifdef IPOD_NANO2G + [PWRMGMT1] = PWRMGMT1_VMIDSEL_500K | PWRMGMT1_VREF, +#else [PWRMGMT1] = PWRMGMT1_VMIDSEL_5K | PWRMGMT1_VREF, +#endif [PWRMGMT2] = PWRMGMT2_DACL | PWRMGMT2_DACR | PWRMGMT2_LOUT1 | PWRMGMT2_ROUT1 | PWRMGMT2_LOUT2 | PWRMGMT2_ROUT2, }; @@ -126,6 +134,37 @@ static void audiohw_mute(bool mute) #define IPOD_PCM_LEVEL 0x65 /* -6dB */ +/* This reduces the popping noise during codec powerup + noticably, especially with high-impedance loads. + We might want to change this for all targets, + but it has only been tested on iPod Nano 2G so far. */ +#ifdef IPOD_NANO2G +void audiohw_preinit(void) +{ + wmcodec_write(RESET, RESET_RESET); + + wmcodec_write(AINTFCE, AINTFCE_MS | AINTFCE_LRP_I2S_RLO + | AINTFCE_IWL_16BIT | AINTFCE_FORMAT_I2S); + +#ifndef IPOD_NANO2G + wmcodec_write(SAMPCTRL, WM8975_44100HZ); +#endif + + wmcodec_write(LOUTMIX1, LOUTMIX1_LD2LO | LOUTMIX1_LI2LOVOL(5)); + wmcodec_write(ROUTMIX2, ROUTMIX2_RD2RO | ROUTMIX2_RI2ROVOL(5)); + + wm8975_write(PWRMGMT1, wm8975_regs[PWRMGMT1]); + wm8975_write(PWRMGMT2, wm8975_regs[PWRMGMT2]); +} + +void audiohw_postinit(void) +{ + wm8975_regs[PWRMGMT1] &= ~PWRMGMT1_VMIDSEL_MASK; + wm8975_regs[PWRMGMT1] |= PWRMGMT1_VMIDSEL_50K; + wm8975_write(PWRMGMT1, wm8975_regs[PWRMGMT1]); + audiohw_mute(false); +} +#else void audiohw_preinit(void) { /* POWER UP SEQUENCE */ @@ -170,7 +209,7 @@ void audiohw_postinit(void) { audiohw_mute(false); } - +#endif void audiohw_set_master_vol(int vol_l, int vol_r) { |