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Diffstat (limited to 'firmware/drivers/audio/wm8978.c')
-rw-r--r--firmware/drivers/audio/wm8978.c21
1 files changed, 9 insertions, 12 deletions
diff --git a/firmware/drivers/audio/wm8978.c b/firmware/drivers/audio/wm8978.c
index 3a86ef204e..69ae608e5d 100644
--- a/firmware/drivers/audio/wm8978.c
+++ b/firmware/drivers/audio/wm8978.c
@@ -155,20 +155,17 @@ static void wmc_write_masked(unsigned int reg, unsigned int bits,
155 * (000000...111111) */ 155 * (000000...111111) */
156static int vol_tenthdb2hw(int db) 156static int vol_tenthdb2hw(int db)
157{ 157{
158 /* -90dB to +6dB 1dB steps (96 levels) 7bits */ 158 /* att DAC AMP result
159 /* 1100000 == +6dB (0x60,96) */ 159 +6dB 0 +6 96
160 /* 1101010 == 0dB (0x5a,90) */ 160 0dB 0 0 90
161 /* 1000001 == -57dB (0x21,33,DAC) */ 161 -57dB 0 -57 33
162 /* 0000001 == -89dB (0x01,01) */ 162 -58dB -1 -57 32
163 /* 0000000 == -90dB (0x00,00,Mute) */ 163 -89dB -32 -57 1
164 if (db < VOLUME_MIN) 164 -90dB -oo -oo 0 */
165 { 165 if (db <= -900)
166 return 0x0; 166 return 0x0;
167 }
168 else 167 else
169 { 168 return db / 10 - -90;
170 return (db - VOLUME_MIN) / 10;
171 }
172} 169}
173 170
174void audiohw_preinit(void) 171void audiohw_preinit(void)