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-rw-r--r--sound/soc/meson/axg-tdm-formatter.c42
1 files changed, 26 insertions, 16 deletions
diff --git a/sound/soc/meson/axg-tdm-formatter.c b/sound/soc/meson/axg-tdm-formatter.c
index 9883dc777f63..63333a2b0a9c 100644
--- a/sound/soc/meson/axg-tdm-formatter.c
+++ b/sound/soc/meson/axg-tdm-formatter.c
@@ -30,27 +30,32 @@ int axg_tdm_formatter_set_channel_masks(struct regmap *map,
struct axg_tdm_stream *ts,
unsigned int offset)
{
- unsigned int val, ch = ts->channels;
- unsigned long mask;
- int i, j;
+ unsigned int ch = ts->channels;
+ u32 val[AXG_TDM_NUM_LANES];
+ int i, j, k;
+
+ /*
+ * We need to mimick the slot distribution used by the HW to keep the
+ * channel placement consistent regardless of the number of channel
+ * in the stream. This is why the odd algorithm below is used.
+ */
+ memset(val, 0, sizeof(*val) * AXG_TDM_NUM_LANES);
/*
* Distribute the channels of the stream over the available slots
- * of each TDM lane
+ * of each TDM lane. We need to go over the 32 slots ...
*/
- for (i = 0; i < AXG_TDM_NUM_LANES; i++) {
- val = 0;
- mask = ts->mask[i];
-
- for (j = find_first_bit(&mask, 32);
- (j < 32) && ch;
- j = find_next_bit(&mask, 32, j + 1)) {
- val |= 1 << j;
- ch -= 1;
+ for (i = 0; (i < 32) && ch; i += 2) {
+ /* ... of all the lanes ... */
+ for (j = 0; j < AXG_TDM_NUM_LANES; j++) {
+ /* ... then distribute the channels in pairs */
+ for (k = 0; k < 2; k++) {
+ if ((BIT(i + k) & ts->mask[j]) && ch) {
+ val[j] |= BIT(i + k);
+ ch -= 1;
+ }
+ }
}
-
- regmap_write(map, offset, val);
- offset += regmap_get_reg_stride(map);
}
/*
@@ -63,6 +68,11 @@ int axg_tdm_formatter_set_channel_masks(struct regmap *map,
return -EINVAL;
}
+ for (i = 0; i < AXG_TDM_NUM_LANES; i++) {
+ regmap_write(map, offset, val[i]);
+ offset += regmap_get_reg_stride(map);
+ }
+
return 0;
}
EXPORT_SYMBOL_GPL(axg_tdm_formatter_set_channel_masks);