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fiiom3k: power down amp before switching DAC power modes

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As detailed in the <Low Power Mode> section of the AK4376A
datasheet, the amp should be powered down before switching
power modes (or to a sample rate <= 12 KHz).

Change-Id: I3ab0a21c78a3ad2bb418b64c916f7dbe2a843efa
This commit is contained in:
Aidan MacDonald 2022-01-10 22:33:42 +00:00
parent dac3175445
commit d93e054419
1 changed files with 19 additions and 1 deletions
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20
firmware/drivers/audio/ak4376.c
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@ -245,8 +245,26 @@ void ak4376_set_freqmode(int fsel, int mult, int power_mode)
if(power_mode == SOUND_LOW_POWER || hw_freq_sampr[fsel] <= SAMPR_12)
mode_ctrl |= 0x40;
/* Handle the LPMODE bit */
int pwr3 = power_mode == SOUND_LOW_POWER ? 0x11 : 0x01;
/* The datasheet says the HP amp must be powered down before changing
* the operating mode of the DAC or HP amp. I'm assuming this means
* the amp must be shut down when changing DSMLP or LPMODE. */
int cur_mode_ctrl = ak4376_read(AK4376_REG_MODE_CTRL);
int cur_pwr3 = ak4376_read(AK4376_REG_PWR3);
bool disable_amp = mode_ctrl != cur_mode_ctrl || pwr3 != cur_pwr3;
/* Program the new settings */
if(disable_amp)
ak4376_write(AK4376_REG_PWR4, 0x00);
ak4376_write(AK4376_REG_CLOCK_MODE, clock_mode);
ak4376_write(AK4376_REG_MODE_CTRL, mode_ctrl);
ak4376_write(AK4376_REG_PWR3, power_mode == SOUND_LOW_POWER ? 0x11 : 0x01);
ak4376_write(AK4376_REG_PWR3, pwr3);
if(disable_amp) {
ak4376_write(AK4376_REG_PWR4, 0x03);
mdelay(26);
}
}