Re: [PATCH 20/21] ASoC: sun4i-i2s: Add support for TDM slots

Sergey Suloev <ssuloev@xxxxxxxxxxxxx> · Fri, 23 Aug 2019 12:09:17 +0300

Hi, Maxime,

On 8/21/19 3:05 PM, Maxime Ripard wrote:
Hi,

On Tue, Aug 20, 2019 at 08:46:30AM +0300, Sergey Suloev wrote:
Hi, Maxime,

On 8/19/19 10:25 PM, Maxime Ripard wrote:
From: Maxime Ripard <maxime.ripard@xxxxxxxxxxx>

The i2s controller supports TDM, for up to 8 slots. Let's support the TDM
API.

Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxx>
---
   sound/soc/sunxi/sun4i-i2s.c | 40 ++++++++++++++++++++++++++++++++------
   1 file changed, 34 insertions(+), 6 deletions(-)

diff --git a/sound/soc/sunxi/sun4i-i2s.c b/sound/soc/sunxi/sun4i-i2s.c
index 0dac09814b65..4f76daeaaed7 100644
--- a/sound/soc/sunxi/sun4i-i2s.c
+++ b/sound/soc/sunxi/sun4i-i2s.c
@@ -168,6 +168,8 @@ struct sun4i_i2s {
   	struct reset_control *rst;
   	unsigned int	mclk_freq;
+	unsigned int	slots;
+	unsigned int	slot_width;
   	struct snd_dmaengine_dai_dma_data	capture_dma_data;
   	struct snd_dmaengine_dai_dma_data	playback_dma_data;
@@ -287,7 +289,7 @@ static bool sun4i_i2s_oversample_is_valid(unsigned int oversample)
   static int sun4i_i2s_set_clk_rate(struct snd_soc_dai *dai,
   				  unsigned int rate,
-				  unsigned int channels,
+				  unsigned int slots,
   				  unsigned int word_size)
   {
   	struct sun4i_i2s *i2s = snd_soc_dai_get_drvdata(dai);
@@ -335,7 +337,7 @@ static int sun4i_i2s_set_clk_rate(struct snd_soc_dai *dai,
   	bclk_parent_rate = i2s->variant->get_bclk_parent_rate(i2s);
   	bclk_div = sun4i_i2s_get_bclk_div(i2s, bclk_parent_rate,
-					  rate, channels, word_size);
+					  rate, slots, word_size);
   	if (bclk_div < 0) {
   		dev_err(dai->dev, "Unsupported BCLK divider: %d\n", bclk_div);
   		return -EINVAL;
@@ -419,6 +421,10 @@ static int sun8i_i2s_set_chan_cfg(const struct sun4i_i2s *i2s,
   				  const struct snd_pcm_hw_params *params)
   {
   	unsigned int channels = params_channels(params);
+	unsigned int slots = channels;
+
+	if (i2s->slots)
+		slots = i2s->slots;
   	/* Map the channels for playback and capture */
   	regmap_write(i2s->regmap, SUN8I_I2S_TX_CHAN_MAP_REG, 0x76543210);
@@ -428,7 +434,6 @@ static int sun8i_i2s_set_chan_cfg(const struct sun4i_i2s *i2s,
   	regmap_update_bits(i2s->regmap, SUN8I_I2S_TX_CHAN_SEL_REG,
   			   SUN4I_I2S_CHAN_SEL_MASK,
   			   SUN4I_I2S_CHAN_SEL(channels));
-
   	regmap_update_bits(i2s->regmap, SUN8I_I2S_RX_CHAN_SEL_REG,
   			   SUN4I_I2S_CHAN_SEL_MASK,
   			   SUN4I_I2S_CHAN_SEL(channels));
@@ -452,10 +457,18 @@ static int sun4i_i2s_hw_params(struct snd_pcm_substream *substream,
   			       struct snd_soc_dai *dai)
   {
   	struct sun4i_i2s *i2s = snd_soc_dai_get_drvdata(dai);
+	unsigned int word_size = params_width(params);
   	unsigned int channels = params_channels(params);
+	unsigned int slots = channels;
   	int ret, sr, wss;
   	u32 width;
+	if (i2s->slots)
+		slots = i2s->slots;
+
+	if (i2s->slot_width)
+		word_size = i2s->slot_width;
+
   	ret = i2s->variant->set_chan_cfg(i2s, params);
   	if (ret < 0) {
   		dev_err(dai->dev, "Invalid channel configuration\n");
@@ -477,15 +490,14 @@ static int sun4i_i2s_hw_params(struct snd_pcm_substream *substream,
   	if (sr < 0)
   		return -EINVAL;
-	wss = i2s->variant->get_wss(i2s, params_width(params));
+	wss = i2s->variant->get_wss(i2s, word_size);
   	if (wss < 0)
   		return -EINVAL;
   	regmap_field_write(i2s->field_fmt_wss, wss);
   	regmap_field_write(i2s->field_fmt_sr, sr);
-	return sun4i_i2s_set_clk_rate(dai, params_rate(params),
-				      channels, params_width(params));
+	return sun4i_i2s_set_clk_rate(dai, params_rate(params), slots, word_size);
   }
   static int sun4i_i2s_set_soc_fmt(const struct sun4i_i2s *i2s,
@@ -785,10 +797,26 @@ static int sun4i_i2s_set_sysclk(struct snd_soc_dai *dai, int clk_id,
   	return 0;
   }
+static int sun4i_i2s_set_tdm_slot(struct snd_soc_dai *dai,
+				  unsigned int tx_mask, unsigned int rx_mask,
+				  int slots, int slot_width)
+{
+	struct sun4i_i2s *i2s = snd_soc_dai_get_drvdata(dai);
+
+	if (slots > 8)
+		return -EINVAL;
+
+	i2s->slots = slots;
+	i2s->slot_width = slot_width;
+
+	return 0;
+}
+
   static const struct snd_soc_dai_ops sun4i_i2s_dai_ops = {
   	.hw_params	= sun4i_i2s_hw_params,
   	.set_fmt	= sun4i_i2s_set_fmt,
   	.set_sysclk	= sun4i_i2s_set_sysclk,
+	.set_tdm_slot	= sun4i_i2s_set_tdm_slot,
   	.trigger	= sun4i_i2s_trigger,
   };
it seems like you forgot to implement sun4i_i2s_dai_ops.set_bclk_ratio
because, as I far as I understand, it should alter tdm slots functionality
indirectly.
As far as I can see, while this indeed changes a few things on the TDM
setup, it's optional, orthogonal and it has a single user in the tree
(some intel platform card).

So I'd say that if someone ever needs it, we can have it, but it's not
a blocker.

"orthogonal" meaning that one can achieve the same effect with using 
"sun4i_i2s_set_tdm_slot" instead of "set_bclk_ratio" ?

For example, for WM8731 codec in "non-USB" master mode should generate 
BCLK = 64 * FS, and I had to implement "set_bclk_ratio" in order to 
setup it. Note, that this is 100% mandatory condition for the code to 
operate in this mode.

Did you mean that now the correct way would be using 
"sun4i_i2s_set_tdm_slot" instead ?


Thank you



Maxime

--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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