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Commit f55f1475 authored by Fabio Estevam's avatar Fabio Estevam Committed by Mark Brown
Browse files

ASoC: mxs-saif: Fix channel swap for 24-bit format 



Playing 24-bit format file leads to channel swap on mx28 and the reason is that
the current driver performs one write/read to/from the SAIF_DATA register to
trigger the transfer.

This approach works fine for S16_LE case because SAIF_DATA is a 32-bit register
and thus is capable of storing the 16-bit left and right channels, but for the
S24_LE case it can only store one channel, so in order to not lose the FIFO sync
an extra read/write is needed.

Reported-by: default avatarDan Winner <DWinner@tc-helicon.com>
Signed-off-by: default avatarFabio Estevam <fabio.estevam@freescale.com>
Tested-by: default avatarDan Winner <DWinner@tc-helicon.com>
Acked-by: default avatarDong Aisheng <dong.aisheng@linaro.org>
Signed-off-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
parent 9f4c3f1c

sound/soc/mxs/mxs-saif.c

+12 −4
Original line number Diff line number Diff line
@@ -523,16 +523,24 @@ static int mxs_saif_trigger(struct snd_pcm_substream *substream, int cmd, 


		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {

			/*

			 * write a data to saif data register to trigger

			 * the transfer

			 * write data to saif data register to trigger

			 * the transfer.

			 * For 24-bit format the 32-bit FIFO register stores

			 * only one channel, so we need to write twice.

			 * This is also safe for the other non 24-bit formats.

			 */

			__raw_writel(0, saif->base + SAIF_DATA);

			__raw_writel(0, saif->base + SAIF_DATA);

		} else {

			/*

			 * read a data from saif data register to trigger

			 * the receive

			 * read data from saif data register to trigger

			 * the receive.

			 * For 24-bit format the 32-bit FIFO register stores

			 * only one channel, so we need to read twice.

			 * This is also safe for the other non 24-bit formats.

			 */

			__raw_readl(saif->base + SAIF_DATA);

			__raw_readl(saif->base + SAIF_DATA);

		}



		master_saif->ongoing = 1;