path: root/sound
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authorArnaud Mouiche <>2016-05-03 14:14:00 +0200
committerMark Brown <>2016-05-13 12:15:31 +0100
commit027db2e122db81b055a2b569d72f2f1d29c4d007 (patch)
tree924ec6c33029c17eebbc19a562613a6975846dbe /sound
parent61fcf10a0ee44763e0347b297a377137f8950772 (diff)
ASoC: fsl_ssi: Fix channel slipping on capture (or playback) restart in full duplex.
Happened when the Playback (or Capture) is running continuously and Capture (or Playback) is restarted (xrun, manual stop/start...) Since the RX (or TX) FIFO are only reset when the whole SSI is disabled, pending samples from previous capture (or playback) session may still be present. They must be erased to not introduce channel slipping. FIFO Clear register fields are documented in IMX51, IMX35 reference manual. They are not documented in IMX50 or IMX6 RM, despite they are working as expected on IMX6SL and IMX6solo. Signed-off-by: Arnaud Mouiche <> Reviewed-by: Fabio Estevam <> Tested-by: Caleb Crome <> Signed-off-by: Mark Brown <>
Diffstat (limited to 'sound')
1 files changed, 22 insertions, 0 deletions
diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c
index 8944af542b4f..d2dd47d2d500 100644
--- a/sound/soc/fsl/fsl_ssi.c
+++ b/sound/soc/fsl/fsl_ssi.c
@@ -401,6 +401,26 @@ static void fsl_ssi_rxtx_config(struct fsl_ssi_private *ssi_private,
+ * Clear RX or TX FIFO to remove samples from the previous
+ * stream session which may be still present in the FIFO and
+ * may introduce bad samples and/or channel slipping.
+ *
+ * Note: The SOR is not documented in recent IMX datasheet, but
+ * is described in IMX51 reference manual at section
+ */
+static void fsl_ssi_fifo_clear(struct fsl_ssi_private *ssi_private,
+ bool is_rx)
+ if (is_rx) {
+ regmap_update_bits(ssi_private->regs, CCSR_SSI_SOR,
+ } else {
+ regmap_update_bits(ssi_private->regs, CCSR_SSI_SOR,
+ }
* Calculate the bits that have to be disabled for the current stream that is
* getting disabled. This keeps the bits enabled that are necessary for the
* second stream to work if 'stream_active' is true.
@@ -475,6 +495,8 @@ static void fsl_ssi_config(struct fsl_ssi_private *ssi_private, bool enable,
* (online configuration)
if (enable) {
+ fsl_ssi_fifo_clear(ssi_private, vals->scr & CCSR_SSI_SCR_RE);
regmap_update_bits(regs, CCSR_SSI_SRCR, vals->srcr, vals->srcr);
regmap_update_bits(regs, CCSR_SSI_STCR, vals->stcr, vals->stcr);
regmap_update_bits(regs, CCSR_SSI_SIER, vals->sier, vals->sier);