[PATCH v3 2/4] ASoc: fsl: fsl_qmc_audio: Ensure audio channels are ordered in TDM bus

[Christophe Leroy]

To reduce complexity of interrupt handling in following patch, ensure
audio channels are configured in the same order as timeslots on the
TDM bus. If we need a given ordering of audio sources in the audio
frame, it is possible to re-order codecs on the TDM bus, no need to
mix up timeslots in channels.

Signed-off-by: Christophe Leroy <christophe.leroy at csgroup.eu>
---
 sound/soc/fsl/fsl_qmc_audio.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/sound/soc/fsl/fsl_qmc_audio.c b/sound/soc/fsl/fsl_qmc_audio.c
index 5614a8b909ed..c0c7ef0a1511 100644
--- a/sound/soc/fsl/fsl_qmc_audio.c
+++ b/sound/soc/fsl/fsl_qmc_audio.c
@@ -791,12 +791,17 @@ static int qmc_audio_dai_parse(struct qmc_audio *qmc_audio, struct device_node *
 			       struct qmc_dai *qmc_dai,
 			       struct snd_soc_dai_driver *qmc_soc_dai_driver)
 {
+	struct qmc_chan_ts_info ts_info;
 	struct qmc_chan_info info;
 	unsigned long rx_fs_rate;
 	unsigned long tx_fs_rate;
+	int prev_last_rx_ts = 0;
+	int prev_last_tx_ts = 0;
 	unsigned int nb_tx_ts;
 	unsigned int nb_rx_ts;
 	unsigned int i;
+	int last_rx_ts;
+	int last_tx_ts;
 	int count;
 	u32 val;
 	int ret;
@@ -879,6 +884,30 @@ static int qmc_audio_dai_parse(struct qmc_audio *qmc_audio, struct device_node *
 				return -EINVAL;
 			}
 		}
+
+		ret = qmc_chan_get_ts_info(qmc_dai->chans[i].qmc_chan, &ts_info);
+		if (ret) {
+			dev_err(qmc_audio->dev, "dai %d get QMC %d channel TS info failed %d\n",
+				qmc_dai->id, i, ret);
+			return ret;
+		}
+
+		last_rx_ts = fls64(ts_info.rx_ts_mask);
+		last_tx_ts = fls64(ts_info.tx_ts_mask);
+
+		if (prev_last_rx_ts > last_rx_ts) {
+			dev_err(qmc_audio->dev, "dai %d QMC chan %d unordered channels (RX timeslot %d before %d)\n",
+				qmc_dai->id, i, prev_last_rx_ts, last_rx_ts);
+			return -EINVAL;
+		}
+		if (prev_last_tx_ts > last_tx_ts) {
+			dev_err(qmc_audio->dev, "dai %d QMC chan %d unordered channels (TX timeslot %d before %d)\n",
+				qmc_dai->id, i, prev_last_tx_ts, last_tx_ts);
+			return -EINVAL;
+		}
+
+		prev_last_rx_ts = last_rx_ts;
+		prev_last_tx_ts = last_tx_ts;
 	}
 
 	qmc_dai->nb_chans_avail = count;
-- 
2.49.0