ASoC: fsl-sai: using 'lsb-first' property instead of 'big-endian-data'.

The 'big-endian-data' property is originally used to indicate whether the
LSB firstly or MSB firstly will be transmitted to the CODEC or received
from the CODEC, and there has nothing relation to the memory data.

Generally, if the audio data in big endian format, which will be using the
bytes reversion, Here this can only be used to bits reversion.

So using the 'lsb-first' instead of 'big-endian-data' can make the code
to be readable easier and more easy to understand what this property is
used to do.

This property used for configuring whether the LSB or the MSB is transmitted
first for the fifo data.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Acked-by: Nicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/fsl-sai.txt

@@ -20,9 +20,9 @@ Required properties:
   See ../pinctrl/pinctrl-bindings.txt for details of the property values.
 - big-endian: Boolean property, required if all the FTM_PWM registers
   are big-endian rather than little-endian.
-- big-endian-data: If this property is absent, the little endian mode will
-  be in use as default, or the big endian mode will be in use for all the
-  fifo data.
+- lsb-first: Configures whether the LSB or the MSB is transmitted first for
+  the fifo data. If this property is absent, the MSB is transmitted first as
+  default, or the LSB is transmitted first.
 - fsl,sai-synchronous-rx: This is a boolean property. If present, indicating
   that SAI will work in the synchronous mode (sync Tx with Rx) which means
   both the transimitter and receiver will send and receive data by following
@@ -53,5 +53,5 @@ sai2: sai@40031000 {
 	      dmas = <&edma0 0 VF610_EDMA_MUXID0_SAI2_TX>,
 		   <&edma0 0 VF610_EDMA_MUXID0_SAI2_RX>;
 	      big-endian;
-	      big-endian-data;
+	      lsb-first;
 };

sound/soc/fsl/fsl_sai.c

@@ -175,7 +175,7 @@ static int fsl_sai_set_dai_fmt_tr(struct snd_soc_dai *cpu_dai,
 	bool tx = fsl_dir == FSL_FMT_TRANSMITTER;
 	u32 val_cr2 = 0, val_cr4 = 0;
 
-	if (!sai->big_endian_data)
+	if (!sai->is_lsb_first)
 		val_cr4 |= FSL_SAI_CR4_MF;
 
 	/* DAI mode */
@@ -304,7 +304,7 @@ static int fsl_sai_hw_params(struct snd_pcm_substream *substream,
 	val_cr5 |= FSL_SAI_CR5_WNW(word_width);
 	val_cr5 |= FSL_SAI_CR5_W0W(word_width);
 
-	if (sai->big_endian_data)
+	if (sai->is_lsb_first)
 		val_cr5 |= FSL_SAI_CR5_FBT(0);
 	else
 		val_cr5 |= FSL_SAI_CR5_FBT(word_width - 1);
@@ -573,7 +573,7 @@ static int fsl_sai_probe(struct platform_device *pdev)
 	if (of_device_is_compatible(pdev->dev.of_node, "fsl,imx6sx-sai"))
 		sai->sai_on_imx = true;
 
-	sai->big_endian_data = of_property_read_bool(np, "big-endian-data");
+	sai->is_lsb_first = of_property_read_bool(np, "lsb-first");
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	base = devm_ioremap_resource(&pdev->dev, res);

sound/soc/fsl/fsl_sai.h

@@ -132,7 +132,7 @@ struct fsl_sai {
 	struct clk *bus_clk;
 	struct clk *mclk_clk[FSL_SAI_MCLK_MAX];
 
-	bool big_endian_data;
+	bool is_lsb_first;
 	bool is_dsp_mode;
 	bool sai_on_imx;
 	bool synchronous[2];