ASoC: rockchip: i2s: switch BCLK to GPIO

We discoverd that the state of BCLK on, LRCLK off and SD_MODE on
may cause the speaker melting issue. Removing LRCLK while BCLK
is present can cause unexpected output behavior including a large
DC output voltage as described in the Max98357a datasheet.

In order to:
  1. prevent BCLK from turning on by other component.
  2. keep BCLK and LRCLK being present at the same time

This patch switches BCLK to GPIO func before LRCLK output, and
configures BCLK func back during LRCLK is output.

Without this fix, BCLK is turned on 11 ms earlier than LRCK by the
da7219.
With this fix, BCLK is turned on only 0.4 ms earlier than LRCK by
the rockchip codec.
Signed-off-by: Judy Hsiao <judyhsiao@chromium.org>
Link: https://lore.kernel.org/r/20220615045643.3137287-1-judyhsiao@chromium.orgSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/rockchip/rockchip_i2s.c

@@ -13,6 +13,7 @@
 #include <linux/of_gpio.h>
 #include <linux/of_device.h>
 #include <linux/clk.h>
+#include <linux/pinctrl/consumer.h>
 #include <linux/pm_runtime.h>
 #include <linux/regmap.h>
 #include <linux/spinlock.h>
@@ -54,8 +55,40 @@ struct rk_i2s_dev {
 	const struct rk_i2s_pins *pins;
 	unsigned int bclk_ratio;
 	spinlock_t lock; /* tx/rx lock */
+	struct pinctrl *pinctrl;
+	struct pinctrl_state *bclk_on;
+	struct pinctrl_state *bclk_off;
 };
 
+static int i2s_pinctrl_select_bclk_on(struct rk_i2s_dev *i2s)
+{
+	int ret = 0;
+
+	if (!IS_ERR(i2s->pinctrl) && !IS_ERR_OR_NULL(i2s->bclk_on))
+		ret = pinctrl_select_state(i2s->pinctrl,
+				     i2s->bclk_on);
+
+	if (ret)
+		dev_err(i2s->dev, "bclk enable failed %d\n", ret);
+
+	return ret;
+}
+
+static int i2s_pinctrl_select_bclk_off(struct rk_i2s_dev *i2s)
+{
+
+	int ret = 0;
+
+	if (!IS_ERR(i2s->pinctrl) && !IS_ERR_OR_NULL(i2s->bclk_off))
+		ret = pinctrl_select_state(i2s->pinctrl,
+				     i2s->bclk_off);
+
+	if (ret)
+		dev_err(i2s->dev, "bclk disable failed %d\n", ret);
+
+	return ret;
+}
+
 static int i2s_runtime_suspend(struct device *dev)
 {
 	struct rk_i2s_dev *i2s = dev_get_drvdata(dev);
@@ -92,38 +125,49 @@ static inline struct rk_i2s_dev *to_info(struct snd_soc_dai *dai)
 	return snd_soc_dai_get_drvdata(dai);
 }
 
-static void rockchip_snd_txctrl(struct rk_i2s_dev *i2s, int on)
+static int rockchip_snd_txctrl(struct rk_i2s_dev *i2s, int on)
 {
 	unsigned int val = 0;
 	int retry = 10;
+	int ret = 0;
 
 	spin_lock(&i2s->lock);
 	if (on) {
-		regmap_update_bits(i2s->regmap, I2S_DMACR,
+		ret = regmap_update_bits(i2s->regmap, I2S_DMACR,
 				I2S_DMACR_TDE_ENABLE, I2S_DMACR_TDE_ENABLE);
+		if (ret < 0)
+			goto end;
 
-		regmap_update_bits(i2s->regmap, I2S_XFER,
+		ret = regmap_update_bits(i2s->regmap, I2S_XFER,
 				I2S_XFER_TXS_START | I2S_XFER_RXS_START,
 				I2S_XFER_TXS_START | I2S_XFER_RXS_START);
+		if (ret < 0)
+			goto end;
 
 		i2s->tx_start = true;
 	} else {
 		i2s->tx_start = false;
 
-		regmap_update_bits(i2s->regmap, I2S_DMACR,
+		ret = regmap_update_bits(i2s->regmap, I2S_DMACR,
 				I2S_DMACR_TDE_ENABLE, I2S_DMACR_TDE_DISABLE);
+		if (ret < 0)
+			goto end;
 
 		if (!i2s->rx_start) {
-			regmap_update_bits(i2s->regmap, I2S_XFER,
+			ret = regmap_update_bits(i2s->regmap, I2S_XFER,
 					I2S_XFER_TXS_START |
 					I2S_XFER_RXS_START,
 					I2S_XFER_TXS_STOP |
 					I2S_XFER_RXS_STOP);
+			if (ret < 0)
+				goto end;
 
 			udelay(150);
-			regmap_update_bits(i2s->regmap, I2S_CLR,
+			ret = regmap_update_bits(i2s->regmap, I2S_CLR,
 					I2S_CLR_TXC | I2S_CLR_RXC,
 					I2S_CLR_TXC | I2S_CLR_RXC);
+			if (ret < 0)
+				goto end;
 
 			regmap_read(i2s->regmap, I2S_CLR, &val);
 
@@ -138,44 +182,57 @@ static void rockchip_snd_txctrl(struct rk_i2s_dev *i2s, int on)
 			}
 		}
 	}
+end:
 	spin_unlock(&i2s->lock);
+	if (ret < 0)
+		dev_err(i2s->dev, "lrclk update failed\n");
+
+	return ret;
 }
 
-static void rockchip_snd_rxctrl(struct rk_i2s_dev *i2s, int on)
+static int rockchip_snd_rxctrl(struct rk_i2s_dev *i2s, int on)
 {
 	unsigned int val = 0;
 	int retry = 10;
+	int ret = 0;
 
 	spin_lock(&i2s->lock);
 	if (on) {
-		regmap_update_bits(i2s->regmap, I2S_DMACR,
+		ret = regmap_update_bits(i2s->regmap, I2S_DMACR,
 				   I2S_DMACR_RDE_ENABLE, I2S_DMACR_RDE_ENABLE);
+		if (ret < 0)
+			goto end;
 
-		regmap_update_bits(i2s->regmap, I2S_XFER,
+		ret = regmap_update_bits(i2s->regmap, I2S_XFER,
 				   I2S_XFER_TXS_START | I2S_XFER_RXS_START,
 				   I2S_XFER_TXS_START | I2S_XFER_RXS_START);
+		if (ret < 0)
+			goto end;
 
 		i2s->rx_start = true;
 	} else {
 		i2s->rx_start = false;
 
-		regmap_update_bits(i2s->regmap, I2S_DMACR,
+		ret = regmap_update_bits(i2s->regmap, I2S_DMACR,
 				   I2S_DMACR_RDE_ENABLE, I2S_DMACR_RDE_DISABLE);
+		if (ret < 0)
+			goto end;
 
 		if (!i2s->tx_start) {
-			regmap_update_bits(i2s->regmap, I2S_XFER,
+			ret = regmap_update_bits(i2s->regmap, I2S_XFER,
 					   I2S_XFER_TXS_START |
 					   I2S_XFER_RXS_START,
 					   I2S_XFER_TXS_STOP |
 					   I2S_XFER_RXS_STOP);
-
+			if (ret < 0)
+				goto end;
 			udelay(150);
-			regmap_update_bits(i2s->regmap, I2S_CLR,
+			ret = regmap_update_bits(i2s->regmap, I2S_CLR,
 					   I2S_CLR_TXC | I2S_CLR_RXC,
 					   I2S_CLR_TXC | I2S_CLR_RXC);
-
+			if (ret < 0)
+				goto end;
 			regmap_read(i2s->regmap, I2S_CLR, &val);
-
 			/* Should wait for clear operation to finish */
 			while (val) {
 				regmap_read(i2s->regmap, I2S_CLR, &val);
@@ -187,7 +244,12 @@ static void rockchip_snd_rxctrl(struct rk_i2s_dev *i2s, int on)
 			}
 		}
 	}
+end:
 	spin_unlock(&i2s->lock);
+	if (ret < 0)
+		dev_err(i2s->dev, "lrclk update failed\n");
+
+	return ret;
 }
 
 static int rockchip_i2s_set_fmt(struct snd_soc_dai *cpu_dai,
@@ -425,17 +487,26 @@ static int rockchip_i2s_trigger(struct snd_pcm_substream *substream,
 	case SNDRV_PCM_TRIGGER_RESUME:
 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 		if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
-			rockchip_snd_rxctrl(i2s, 1);
+			ret = rockchip_snd_rxctrl(i2s, 1);
 		else
-			rockchip_snd_txctrl(i2s, 1);
+			ret = rockchip_snd_txctrl(i2s, 1);
+		/* Do not turn on bclk if lrclk open fails. */
+		if (ret < 0)
+			return ret;
+		i2s_pinctrl_select_bclk_on(i2s);
 		break;
 	case SNDRV_PCM_TRIGGER_SUSPEND:
 	case SNDRV_PCM_TRIGGER_STOP:
 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
-		if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
-			rockchip_snd_rxctrl(i2s, 0);
-		else
-			rockchip_snd_txctrl(i2s, 0);
+		if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
+			if (!i2s->tx_start)
+				i2s_pinctrl_select_bclk_off(i2s);
+			ret = rockchip_snd_rxctrl(i2s, 0);
+		} else {
+			if (!i2s->rx_start)
+				i2s_pinctrl_select_bclk_off(i2s);
+			ret = rockchip_snd_txctrl(i2s, 0);
+		}
 		break;
 	default:
 		ret = -EINVAL;
@@ -736,6 +807,33 @@ static int rockchip_i2s_probe(struct platform_device *pdev)
 	}
 
 	i2s->bclk_ratio = 64;
+	i2s->pinctrl = devm_pinctrl_get(&pdev->dev);
+	if (IS_ERR(i2s->pinctrl))
+		dev_err(&pdev->dev, "failed to find i2s pinctrl\n");
+
+	i2s->bclk_on = pinctrl_lookup_state(i2s->pinctrl,
+				   "bclk_on");
+	if (IS_ERR_OR_NULL(i2s->bclk_on))
+		dev_err(&pdev->dev, "failed to find i2s default state\n");
+	else
+		dev_dbg(&pdev->dev, "find i2s bclk state\n");
+
+	i2s->bclk_off = pinctrl_lookup_state(i2s->pinctrl,
+				  "bclk_off");
+	if (IS_ERR_OR_NULL(i2s->bclk_off))
+		dev_err(&pdev->dev, "failed to find i2s gpio state\n");
+	else
+		dev_dbg(&pdev->dev, "find i2s bclk_off state\n");
+
+	i2s_pinctrl_select_bclk_off(i2s);
+
+	i2s->playback_dma_data.addr = res->start + I2S_TXDR;
+	i2s->playback_dma_data.addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+	i2s->playback_dma_data.maxburst = 4;
+
+	i2s->capture_dma_data.addr = res->start + I2S_RXDR;
+	i2s->capture_dma_data.addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+	i2s->capture_dma_data.maxburst = 4;
 
 	dev_set_drvdata(&pdev->dev, i2s);