i2s: fix a bug when calculating i2s apll parameters

Closes https://github.com/espressif/esp-idf/issues/2634
Closes https://github.com/espressif/esp-idf/issues/3380
Fixes https://github.com/espressif/esp-idf/issues/3407

diff --git a/components/driver/i2s.c b/components/driver/i2s.c
index 085f19b89b07c66dac9e67df25316330891dd664..4592c96bb8497d76d861c04663b58817af910e78 100644 (file)
--- a/components/driver/i2s.c
+++ b/components/driver/i2s.c
@@ -251,7 +251,7 @@ static esp_err_t i2s_apll_calculate_fi2s(int rate, int bits_per_sample, int *sdm
         max_rate = i2s_apll_get_fi2s(bits_per_sample, 255, 255, _sdm2, 0);
         min_rate = i2s_apll_get_fi2s(bits_per_sample, 0, 0, _sdm2, 31);
         avg = (max_rate + min_rate)/2;
-        if(abs(avg - rate) < min_diff) {
+        if (abs(avg - rate) < min_diff) {
             min_diff = abs(avg - rate);
             *sdm2 = _sdm2;
         }
@@ -261,11 +261,21 @@ static esp_err_t i2s_apll_calculate_fi2s(int rate, int bits_per_sample, int *sdm
         max_rate = i2s_apll_get_fi2s(bits_per_sample, 255, 255, *sdm2, _odir);
         min_rate = i2s_apll_get_fi2s(bits_per_sample, 0, 0, *sdm2, _odir);
         avg = (max_rate + min_rate)/2;
-        if(abs(avg - rate) < min_diff) {
+        if (abs(avg - rate) < min_diff) {
             min_diff = abs(avg - rate);
             *odir = _odir;
         }
     }
+    min_diff = APLL_MAX_FREQ;
+    for (_sdm2 = 4; _sdm2 < 9; _sdm2 ++) {
+        max_rate = i2s_apll_get_fi2s(bits_per_sample, 255, 255, _sdm2, *odir);
+        min_rate = i2s_apll_get_fi2s(bits_per_sample, 0, 0, _sdm2, *odir);
+        avg = (max_rate + min_rate)/2;
+        if (abs(avg - rate) < min_diff) {
+            min_diff = abs(avg - rate);
+            *sdm2 = _sdm2;
+        }
+    }
 
     min_diff = APLL_MAX_FREQ;
     for (_sdm1 = 0; _sdm1 < 256; _sdm1 ++) {