ASoC: sun4i-i2s: Fix setting of FIFO modes

Because SUN4I_I2S_FIFO_CTRL_REG is volatile, writes done while the
regmap is cache-only are ignored. To work around this, move the
configuration to a callback that runs while the ASoC core has a
runtime PM reference to the device.
Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Clément Péron <peron.clem@gmail.com>
Link: https://lore.kernel.org/r/20201030144648.397824-9-peron.clem@gmail.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sunxi/sun4i-i2s.c

@@ -596,6 +596,13 @@ static int sun4i_i2s_hw_params(struct snd_pcm_substream *substream,
 		return ret;
 	}
 
+	/* Set significant bits in our FIFOs */
+	regmap_update_bits(i2s->regmap, SUN4I_I2S_FIFO_CTRL_REG,
+			   SUN4I_I2S_FIFO_CTRL_TX_MODE_MASK |
+			   SUN4I_I2S_FIFO_CTRL_RX_MODE_MASK,
+			   SUN4I_I2S_FIFO_CTRL_TX_MODE(1) |
+			   SUN4I_I2S_FIFO_CTRL_RX_MODE(1));
+
 	switch (params_physical_width(params)) {
 	case 16:
 		width = DMA_SLAVE_BUSWIDTH_2_BYTES;
@@ -924,13 +931,6 @@ static int sun4i_i2s_set_fmt(struct snd_soc_dai *dai, unsigned int fmt)
 		return ret;
 	}
 
-	/* Set significant bits in our FIFOs */
-	regmap_update_bits(i2s->regmap, SUN4I_I2S_FIFO_CTRL_REG,
-			   SUN4I_I2S_FIFO_CTRL_TX_MODE_MASK |
-			   SUN4I_I2S_FIFO_CTRL_RX_MODE_MASK,
-			   SUN4I_I2S_FIFO_CTRL_TX_MODE(1) |
-			   SUN4I_I2S_FIFO_CTRL_RX_MODE(1));
-
 	i2s->format = fmt;
 
 	return 0;