ASoC: fsl_ssi: Fix TDM slot setup for I2S mode

When using the driver in I2S TDM mode, the _fsl_ssi_set_dai_fmt()
function rewrites the number of slots previously set by the
fsl_ssi_set_dai_tdm_slot() function to 2 by default.
To fix this, let's use the saved slot count value or, if TDM
is not used and the slot count is not set, proceed as before.

Fixes: 4f14f5c1 ("ASoC: fsl_ssi: Fix number of words per frame for I2S-slave mode")
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Acked-by: Nicolin Chen <nicoleotsuka@gmail.com>
Link: https://lore.kernel.org/r/20210216114221.26635-1-shc_work@mail.ruSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/fsl/fsl_ssi.c

@@ -878,6 +878,7 @@ static int fsl_ssi_hw_free(struct snd_pcm_substream *substream,
 static int _fsl_ssi_set_dai_fmt(struct fsl_ssi *ssi, unsigned int fmt)
 {
 	u32 strcr = 0, scr = 0, stcr, srcr, mask;
+	unsigned int slots;
 
 	ssi->dai_fmt = fmt;
 
@@ -909,10 +910,11 @@ static int _fsl_ssi_set_dai_fmt(struct fsl_ssi *ssi, unsigned int fmt)
 			return -EINVAL;
 		}
 
+		slots = ssi->slots ? : 2;
 		regmap_update_bits(ssi->regs, REG_SSI_STCCR,
-				   SSI_SxCCR_DC_MASK, SSI_SxCCR_DC(2));
+				   SSI_SxCCR_DC_MASK, SSI_SxCCR_DC(slots));
 		regmap_update_bits(ssi->regs, REG_SSI_SRCCR,
-				   SSI_SxCCR_DC_MASK, SSI_SxCCR_DC(2));
+				   SSI_SxCCR_DC_MASK, SSI_SxCCR_DC(slots));
 
 		/* Data on rising edge of bclk, frame low, 1clk before data */
 		strcr |= SSI_STCR_TFSI | SSI_STCR_TSCKP | SSI_STCR_TEFS;