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ASoC: wm8994: VMID management improvements 

Raise the ramp time to 50ms to cover corner cases, use the startup bias
generator, explicitly reset the ramp circuit when complete and reorder
things all of which should improve performance somewhat for systems that
are sensitive to noise from VMID.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This commit is contained in:
Mark Brown 2012-02-11 23:09:53 +00:00
parent d60d6c3b65
commit cc6d5a8c2b
1 changed files with 14 additions and 6 deletions
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20
sound/soc/codecs/wm8994.c
View File

@ -778,29 +778,37 @@ static void vmid_reference(struct snd_soc_codec *codec)
wm8994->vmid_refcount);
if (wm8994->vmid_refcount == 1) {
snd_soc_update_bits(codec, WM8994_ANTIPOP_1,
WM8994_LINEOUT_VMID_BUF_ENA |
WM8994_LINEOUT1_DISCH |
WM8994_LINEOUT2_DISCH,
WM8994_LINEOUT_VMID_BUF_ENA);
/* Startup bias, VMID ramp & buffer */
snd_soc_update_bits(codec, WM8994_ANTIPOP_2,
WM8994_BIAS_SRC |
WM8994_VMID_DISCH |
WM8994_STARTUP_BIAS_ENA |
WM8994_VMID_BUF_ENA |
WM8994_VMID_RAMP_MASK,
WM8994_BIAS_SRC |
WM8994_STARTUP_BIAS_ENA |
WM8994_VMID_BUF_ENA |
(0x3 << WM8994_VMID_RAMP_SHIFT));
wm_hubs_vmid_ena(codec);
/* Remove discharge for line out */
snd_soc_update_bits(codec, WM8994_ANTIPOP_1,
WM8994_LINEOUT1_DISCH |
WM8994_LINEOUT2_DISCH, 0);
/* Main bias enable, VMID=2x40k */
snd_soc_update_bits(codec, WM8994_POWER_MANAGEMENT_1,
WM8994_BIAS_ENA |
WM8994_VMID_SEL_MASK,
WM8994_BIAS_ENA | 0x2);
msleep(20);
msleep(50);
snd_soc_update_bits(codec, WM8994_ANTIPOP_2,
WM8994_VMID_RAMP_MASK | WM8994_BIAS_SRC,
0);
}
}