summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorAidan MacDonald <amachronic@protonmail.com>2022-01-10 22:33:42 +0000
committerAidan MacDonald <amachronic@protonmail.com>2022-01-16 19:35:40 -0500
commitd93e0544198b75542b23b02a8b819d81e98ff880 (patch)
tree95d99b92e02d8b2e68b1ba16a10e63b0308f44b4
parentdac3175445b6e76a29c1550da9cece13dfaf7f8c (diff)
downloadrockbox-d93e0544198b75542b23b02a8b819d81e98ff880.tar.gz
rockbox-d93e0544198b75542b23b02a8b819d81e98ff880.zip
fiiom3k: power down amp before switching DAC power modes
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
-rw-r--r--firmware/drivers/audio/ak4376.c20
1 files changed, 19 insertions, 1 deletions
diff --git a/firmware/drivers/audio/ak4376.c b/firmware/drivers/audio/ak4376.c
index 2e772ace84..8d2b9f44f3 100644
--- a/firmware/drivers/audio/ak4376.c
+++ b/firmware/drivers/audio/ak4376.c
@@ -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);
+ }
}