[alsa-devel] [PATCH 1/2] ASoC: pxa-ssp: allow more flexible setup order

[Daniel Mack]

The pxa-ssp driver currently assumes that .set_fmt() is called before
.set_clkdiv(), .set_pll() etc.

Commit a8bd0ee558714 ("ASoC: raumfeld: Use static DAI format setup") broke
support for Raumfeld hardware (and possible other PXA based ones) because
it effectively changed the order of these calls. Also, as the call to
.set_fmt() is now done at probe time, the port clock is not yet enabled.

To fix this, strip all hardware register access code from the .set_fmt()
callback and memorize the desired value, so we can use it from the
.hw_params() callback. Also make the .set_fmt() callback less destructive
by reading all registers that it writes to in the beginning and only
masking out the bits that it possibly fiddles with.

Signed-off-by: Daniel Mack <daniel at zonque.org>
---
 sound/soc/pxa/pxa-ssp.c | 82 +++++++++++++++++++++++++++++++++++++------------
 1 file changed, 62 insertions(+), 20 deletions(-)

diff --git a/sound/soc/pxa/pxa-ssp.c b/sound/soc/pxa/pxa-ssp.c
index a0189b88f1d2..fbed87d824b8 100644
--- a/sound/soc/pxa/pxa-ssp.c
+++ b/sound/soc/pxa/pxa-ssp.c
@@ -43,7 +43,8 @@
 struct ssp_priv {
 	struct ssp_device *ssp;
 	unsigned int sysclk;
-	int dai_fmt;
+	unsigned int dai_fmt;
+	unsigned int configured_dai_fmt;
 #ifdef CONFIG_PM
 	uint32_t	cr0;
 	uint32_t	cr1;
@@ -432,36 +433,72 @@ static int pxa_ssp_set_dai_tristate(struct snd_soc_dai *cpu_dai,
 	return 0;
 }
 
+static int pxa_ssp_set_dai_fmt(struct snd_soc_dai *cpu_dai,
+			       unsigned int fmt)
+{
+	struct ssp_priv *priv = snd_soc_dai_get_drvdata(cpu_dai);
+
+	switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
+	case SND_SOC_DAIFMT_CBM_CFM:
+	case SND_SOC_DAIFMT_CBM_CFS:
+	case SND_SOC_DAIFMT_CBS_CFS:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
+	case SND_SOC_DAIFMT_NB_NF:
+	case SND_SOC_DAIFMT_NB_IF:
+	case SND_SOC_DAIFMT_IB_IF:
+	case SND_SOC_DAIFMT_IB_NF:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
+	case SND_SOC_DAIFMT_I2S:
+	case SND_SOC_DAIFMT_DSP_A:
+	case SND_SOC_DAIFMT_DSP_B:
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	/* Settings will be applied in hw_params() */
+	priv->dai_fmt = fmt;
+
+	return 0;
+}
+
 /*
  * Set up the SSP DAI format.
  * The SSP Port must be inactive before calling this function as the
  * physical interface format is changed.
  */
-static int pxa_ssp_set_dai_fmt(struct snd_soc_dai *cpu_dai,
-		unsigned int fmt)
+static int pxa_ssp_configure_dai_fmt(struct ssp_priv *priv)
 {
-	struct ssp_priv *priv = snd_soc_dai_get_drvdata(cpu_dai);
 	struct ssp_device *ssp = priv->ssp;
 	u32 sscr0, sscr1, sspsp, scfr;
 
 	/* check if we need to change anything at all */
-	if (priv->dai_fmt == fmt)
+	if (priv->configured_dai_fmt == priv->dai_fmt)
 		return 0;
 
-	/* we can only change the settings if the port is not in use */
-	if (pxa_ssp_read_reg(ssp, SSCR0) & SSCR0_SSE) {
-		dev_err(&ssp->pdev->dev,
-			"can't change hardware dai format: stream is in use");
-		return -EINVAL;
-	}
-
 	/* reset port settings */
 	sscr0 = pxa_ssp_read_reg(ssp, SSCR0) &
-		~(SSCR0_ECS |  SSCR0_NCS | SSCR0_MOD | SSCR0_ACS);
-	sscr1 = SSCR1_RxTresh(8) | SSCR1_TxTresh(7);
-	sspsp = 0;
+		~(SSCR0_PSP | SSCR0_MOD);
+	sscr1 = pxa_ssp_read_reg(ssp, SSCR1) &
+		~(SSCR1_SCLKDIR | SSCR1_SFRMDIR | SSCR1_SCFR |
+		  SSCR1_RWOT | SSCR1_TRAIL | SSCR1_TFT | SSCR1_RFT);
+	sspsp = pxa_ssp_read_reg(ssp, SSPSP) &
+		~(SSPSP_SFRMP | SSPSP_SCMODE(3));
 
-	switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
+	sscr1 |= SSCR1_RxTresh(8) | SSCR1_TxTresh(7);
+
+	switch (priv->dai_fmt & SND_SOC_DAIFMT_MASTER_MASK) {
 	case SND_SOC_DAIFMT_CBM_CFM:
 		sscr1 |= SSCR1_SCLKDIR | SSCR1_SFRMDIR | SSCR1_SCFR;
 		break;
@@ -474,7 +511,7 @@ static int pxa_ssp_set_dai_fmt(struct snd_soc_dai *cpu_dai,
 		return -EINVAL;
 	}
 
-	switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
+	switch (priv->dai_fmt & SND_SOC_DAIFMT_INV_MASK) {
 	case SND_SOC_DAIFMT_NB_NF:
 		sspsp |= SSPSP_SFRMP;
 		break;
@@ -490,7 +527,7 @@ static int pxa_ssp_set_dai_fmt(struct snd_soc_dai *cpu_dai,
 		return -EINVAL;
 	}
 
-	switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
+	switch (priv->dai_fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
 	case SND_SOC_DAIFMT_I2S:
 		sscr0 |= SSCR0_PSP;
 		sscr1 |= SSCR1_RWOT | SSCR1_TRAIL;
@@ -512,7 +549,7 @@ static int pxa_ssp_set_dai_fmt(struct snd_soc_dai *cpu_dai,
 	pxa_ssp_write_reg(ssp, SSCR1, sscr1);
 	pxa_ssp_write_reg(ssp, SSPSP, sspsp);
 
-	switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
+	switch (priv->dai_fmt & SND_SOC_DAIFMT_MASTER_MASK) {
 	case SND_SOC_DAIFMT_CBM_CFM:
 	case SND_SOC_DAIFMT_CBM_CFS:
 		scfr = pxa_ssp_read_reg(ssp, SSCR1) | SSCR1_SCFR;
@@ -529,7 +566,7 @@ static int pxa_ssp_set_dai_fmt(struct snd_soc_dai *cpu_dai,
 	 * we have to defer some things until hw_params() where we
 	 * know parameters like the sample size.
 	 */
-	priv->dai_fmt = fmt;
+	priv->configured_dai_fmt = priv->dai_fmt;
 
 	return 0;
 }
@@ -550,6 +587,7 @@ static int pxa_ssp_hw_params(struct snd_pcm_substream *substream,
 	int width = snd_pcm_format_physical_width(params_format(params));
 	int ttsa = pxa_ssp_read_reg(ssp, SSTSA) & 0xf;
 	struct snd_dmaengine_dai_dma_data *dma_data;
+	int ret;
 
 	dma_data = snd_soc_dai_get_dma_data(cpu_dai, substream);
 
@@ -565,6 +603,10 @@ static int pxa_ssp_hw_params(struct snd_pcm_substream *substream,
 	if (pxa_ssp_read_reg(ssp, SSCR0) & SSCR0_SSE)
 		return 0;
 
+	ret = pxa_ssp_configure_dai_fmt(priv);
+	if (ret < 0)
+		return ret;
+
 	/* clear selected SSP bits */
 	sscr0 = pxa_ssp_read_reg(ssp, SSCR0) & ~(SSCR0_DSS | SSCR0_EDSS);
 
-- 
2.14.3