[PATCH v2 1/3] ASoC: loongson: Fix IISConfig0 update in hw_params for rev 1

[phucduc.bui@gmail.com]

From: bui duc phuc <phucduc.bui@gmail.com>

On revision 1 controllers, loongson_i2s_hw_params() reads LS_I2S_CFG
and ORs the new LR_LEN, BCLK_RATIO and RES_DEPTH values into it
without clearing the old ones.

The first stream after boot is configured correctly, but any later
stream with a different rate or sample width ends up with a mix of
old and new bits, so it may run with the wrong rate or sample width.

Use regmap_update_bits() to replace LR_LEN, BCLK_RATIO and the
RES_DEPTH field for the current direction while preserving the
other direction's RES_DEPTH field.

Fixes: d84881e06836 ("ASoC: Add support for Loongson I2S controller")
Signed-off-by: bui duc phuc <phucduc.bui@gmail.com>
---

Changes in v2:
 - Use FIELD_PREP() for register fields as suggested by Binbin.

 sound/soc/loongson/loongson_i2s.c | 21 +++++++++++++--------
 sound/soc/loongson/loongson_i2s.h |  6 ++++++
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/sound/soc/loongson/loongson_i2s.c b/sound/soc/loongson/loongson_i2s.c
index da0d029c028a..aebea177e7e0 100644
--- a/sound/soc/loongson/loongson_i2s.c
+++ b/sound/soc/loongson/loongson_i2s.c
@@ -6,6 +6,7 @@
 // Author: Yingkun Meng <mengyingkun@loongson.cn>
 //
 
+#include <linux/bitfield.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/delay.h>
@@ -69,6 +70,7 @@ static int loongson_i2s_hw_params(struct snd_pcm_substream *substream,
 	u32 fs = params_rate(params);
 	u32 bclk_ratio, mclk_ratio;
 	u32 mclk_ratio_frac;
+	u32 mask;
 	u32 val = 0;
 
 	switch (i2s->rev_id) {
@@ -92,14 +94,17 @@ static int loongson_i2s_hw_params(struct snd_pcm_substream *substream,
 		mclk_ratio_frac = DIV_ROUND_CLOSEST_ULL(((u64)clk_rate << 16),
 						    sysclk) - (mclk_ratio << 16);
 
-		regmap_read(i2s->regmap, LS_I2S_CFG, &val);
-		val |= (bits << 24);
-		val |= (bclk_ratio << 8);
-		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
-			val |= (bits << 16);
-		else
-			val |= bits;
-		regmap_write(i2s->regmap, LS_I2S_CFG, val);
+		mask = LS_I2S_CFG_LR_LEN_MASK | LS_I2S_CFG_BCLK_RATIO_MASK;
+		val = FIELD_PREP(LS_I2S_CFG_LR_LEN_MASK, bits) |
+		      FIELD_PREP(LS_I2S_CFG_BCLK_RATIO_MASK, bclk_ratio);
+		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+			mask |= LS_I2S_CFG_TX_RES_DEPTH_MASK;
+			val |= FIELD_PREP(LS_I2S_CFG_TX_RES_DEPTH_MASK, bits);
+		} else {
+			mask |= LS_I2S_CFG_RX_RES_DEPTH_MASK;
+			val |= FIELD_PREP(LS_I2S_CFG_RX_RES_DEPTH_MASK, bits);
+		}
+		regmap_update_bits(i2s->regmap, LS_I2S_CFG, mask, val);
 
 		val = (mclk_ratio_frac << 16) | mclk_ratio;
 		regmap_write(i2s->regmap, LS_I2S_CFG1, val);
diff --git a/sound/soc/loongson/loongson_i2s.h b/sound/soc/loongson/loongson_i2s.h
index 8b4603c876c5..457d90e3d5b6 100644
--- a/sound/soc/loongson/loongson_i2s.h
+++ b/sound/soc/loongson/loongson_i2s.h
@@ -40,6 +40,12 @@
 #define I2S_CTRL_RX_INT_EN	BIT(1)  /* RX interrupt enable */
 #define I2S_CTRL_TX_INT_EN	BIT(0)  /* TX interrupt enable */
 
+/* Loongson I2S Config Register */
+#define LS_I2S_CFG_LR_LEN_MASK		GENMASK(31, 24)
+#define LS_I2S_CFG_TX_RES_DEPTH_MASK	GENMASK(23, 16)
+#define LS_I2S_CFG_BCLK_RATIO_MASK	GENMASK(15, 8)
+#define LS_I2S_CFG_RX_RES_DEPTH_MASK	GENMASK(7, 0)		/* rev 1 */
+
 #define LS_I2S_DRVNAME		"loongson-i2s"
 
 struct loongson_idma_data {
-- 
2.43.0