[PATCH 0/2] ASoC: da7219: BCLK and TDM flexibility improvements

[PATCH 0/2] ASoC: da7219: BCLK and TDM flexibility improvements

[Adam Thomson]

This patch set updates the driver to be more flexible regarding the BCLK and
TDM configurations of the device.

Previously the BCLK rate was fixed at 64 periods per WCLK, when the codec is
DAI clock master, but to satisfy devices which prefer a lower rate, and to save
power, the BCLK rate is now calculated based on hw_params() data.

As a fallout of the BCLK efforts it was also apparent that the TDM code could be
made more flexible as well. The device is capable of automatically detecting
the BCLK rate when it is clock slave, so previous limitations imposed were
not necessary. The mask handling is now used as an input to determine the BCLK
offset to align closer with other examples within ALSA.

Adam Thomson (2):
  ASoC: da7219: Add support for master mode BCLK rate adjustment
  ASoC: da7219: Update TDM usage to be more flexible

 sound/soc/codecs/da7219.c | 116 +++++++++++++++++++++++++++++-----------------
 sound/soc/codecs/da7219.h |   1 +
 2 files changed, 74 insertions(+), 43 deletions(-)

-- 
1.9.1

[PATCH 1/2] ASoC: da7219: Add support for master mode BCLK rate adjustment

[Adam Thomson]

Previously the driver would default the BCLK periods per WCLK to
64, to cover all possible non-TDM scenarios when the codec was
DAI clock master. However some devices require a lower BCLK rate
to operate correctly so with this in mind, this commit updates
the code to be more dynamic, with BCLK rate now based on SR and
word length provided to hw_params().

Signed-off-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
---
 sound/soc/codecs/da7219.c | 36 ++++++++++++++++++++++++++----------
 sound/soc/codecs/da7219.h |  1 +
 2 files changed, 27 insertions(+), 10 deletions(-)

diff --git a/sound/soc/codecs/da7219.c b/sound/soc/codecs/da7219.c
index b1df4bb..7dbecf3 100644
--- a/sound/soc/codecs/da7219.c
+++ b/sound/soc/codecs/da7219.c
@@ -1376,11 +1376,7 @@ static int da7219_set_dai_fmt(struct snd_soc_dai *codec_dai, unsigned int fmt)
 		return -EINVAL;
 	}
 
-	/* By default 64 BCLKs per WCLK is supported */
-	dai_clk_mode |= DA7219_DAI_BCLKS_PER_WCLK_64;
-
 	snd_soc_component_update_bits(component, DA7219_DAI_CLK_MODE,
-			    DA7219_DAI_BCLKS_PER_WCLK_MASK |
 			    DA7219_DAI_CLK_POL_MASK | DA7219_DAI_WCLK_POL_MASK,
 			    dai_clk_mode);
 	snd_soc_component_update_bits(component, DA7219_DAI_CTRL, DA7219_DAI_FORMAT_MASK,
@@ -1399,14 +1395,12 @@ static int da7219_set_dai_tdm_slot(struct snd_soc_dai *dai,
 	__le16 offset;
 	u32 frame_size;
 
-	/* No channels enabled so disable TDM, revert to 64-bit frames */
+	/* No channels enabled so disable TDM */
 	if (!tx_mask) {
 		snd_soc_component_update_bits(component, DA7219_DAI_TDM_CTRL,
 				    DA7219_DAI_TDM_CH_EN_MASK |
 				    DA7219_DAI_TDM_MODE_EN_MASK, 0);
-		snd_soc_component_update_bits(component, DA7219_DAI_CLK_MODE,
-				    DA7219_DAI_BCLKS_PER_WCLK_MASK,
-				    DA7219_DAI_BCLKS_PER_WCLK_64);
+		da7219->tdm_en = false;
 		return 0;
 	}
 
@@ -1458,6 +1452,8 @@ static int da7219_set_dai_tdm_slot(struct snd_soc_dai *dai,
 			    (tx_mask << DA7219_DAI_TDM_CH_EN_SHIFT) |
 			    DA7219_DAI_TDM_MODE_EN_MASK);
 
+	da7219->tdm_en = true;
+
 	return 0;
 }
 
@@ -1466,10 +1462,13 @@ static int da7219_hw_params(struct snd_pcm_substream *substream,
 			    struct snd_soc_dai *dai)
 {
 	struct snd_soc_component *component = dai->component;
-	u8 dai_ctrl = 0, fs;
+	struct da7219_priv *da7219 = snd_soc_component_get_drvdata(component);
+	u8 dai_ctrl = 0, dai_bclks_per_wclk = 0, fs;
 	unsigned int channels;
+	int word_len = params_width(params);
+	int frame_size;
 
-	switch (params_width(params)) {
+	switch (word_len) {
 	case 16:
 		dai_ctrl |= DA7219_DAI_WORD_LENGTH_S16_LE;
 		break;
@@ -1533,6 +1532,23 @@ static int da7219_hw_params(struct snd_pcm_substream *substream,
 		return -EINVAL;
 	}
 
+	/*
+	 * If we're master, then we have a limited set of BCLK rates we
+	 * support. For slave mode this isn't the case and the codec can detect
+	 * the BCLK rate automatically.
+	 */
+	if (da7219->master & !da7219->tdm_en) {
+		frame_size = word_len * 2;
+		if (frame_size <= 32)
+			dai_bclks_per_wclk = DA7219_DAI_BCLKS_PER_WCLK_32;
+		else
+			dai_bclks_per_wclk = DA7219_DAI_BCLKS_PER_WCLK_64;
+
+		snd_soc_component_update_bits(component, DA7219_DAI_CLK_MODE,
+					      DA7219_DAI_BCLKS_PER_WCLK_MASK,
+					      dai_bclks_per_wclk);
+	}
+
 	snd_soc_component_update_bits(component, DA7219_DAI_CTRL,
 			    DA7219_DAI_WORD_LENGTH_MASK |
 			    DA7219_DAI_CH_NUM_MASK,
diff --git a/sound/soc/codecs/da7219.h b/sound/soc/codecs/da7219.h
index 366cf46..018819c 100644
--- a/sound/soc/codecs/da7219.h
+++ b/sound/soc/codecs/da7219.h
@@ -830,6 +830,7 @@ struct da7219_priv {
 	int clk_src;
 
 	bool master;
+	bool tdm_en;
 	bool alc_en;
 	bool micbias_on_event;
 	unsigned int mic_pga_delay;
-- 
1.9.1

[PATCH 2/2] ASoC: da7219: Update TDM usage to be more flexible

[Adam Thomson]

The previous implementatation was restrictive with regards to
BCLK rates for slave mode where the driver would not allow rates
the codec couldn't provide itself as clock master. The codec
is able to automatically determine and handle whatever rate is
provided so this restriction isn't necessary for slave mode. The
code was also flawed with regards to setting of the frame offset
as using rx_mask to explicitly set the offset has the knock on
effect of impacting the min and max channels for the codec, in
soc_pcm_hw_params() through the call to
soc_pcm_codec_params_fixup().

With this update, the driver now only limits frame size if codec
is clock master, and dynamically determines the BCLK offset
relating to WCLK using the tx_mask for slot offset along with the
slot width provided.

Signed-off-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
---
 sound/soc/codecs/da7219.c | 80 ++++++++++++++++++++++++++++-------------------
 1 file changed, 47 insertions(+), 33 deletions(-)

diff --git a/sound/soc/codecs/da7219.c b/sound/soc/codecs/da7219.c
index 7dbecf3..be606e3 100644
--- a/sound/soc/codecs/da7219.c
+++ b/sound/soc/codecs/da7219.c
@@ -1391,8 +1391,10 @@ static int da7219_set_dai_tdm_slot(struct snd_soc_dai *dai,
 {
 	struct snd_soc_component *component = dai->component;
 	struct da7219_priv *da7219 = snd_soc_component_get_drvdata(component);
-	u8 dai_bclks_per_wclk;
-	__le16 offset;
+	unsigned int ch_mask;
+	u8 dai_bclks_per_wclk, slot_offset;
+	u16 offset;
+	__le16 dai_offset;
 	u32 frame_size;
 
 	/* No channels enabled so disable TDM */
@@ -1405,51 +1407,63 @@ static int da7219_set_dai_tdm_slot(struct snd_soc_dai *dai,
 	}
 
 	/* Check we have valid slots */
-	if (fls(tx_mask) > DA7219_DAI_TDM_MAX_SLOTS) {
-		dev_err(component->dev, "Invalid number of slots, max = %d\n",
+	slot_offset = ffs(tx_mask) - 1;
+	ch_mask = (tx_mask >> slot_offset);
+	if (fls(ch_mask) > DA7219_DAI_TDM_MAX_SLOTS) {
+		dev_err(component->dev,
+			"Invalid number of slots, max = %d\n",
 			DA7219_DAI_TDM_MAX_SLOTS);
 		return -EINVAL;
 	}
 
-	/* Check we have a valid offset given */
-	if (rx_mask > DA7219_DAI_OFFSET_MAX) {
-		dev_err(component->dev, "Invalid slot offset, max = %d\n",
-			DA7219_DAI_OFFSET_MAX);
+	/*
+	 * Ensure we have a valid offset into the frame, based on slot width
+	 * and slot offset of first slot we're interested in.
+	 */
+	offset = slot_offset * slot_width;
+	if (offset > DA7219_DAI_OFFSET_MAX) {
+		dev_err(component->dev, "Invalid frame offset %d\n", offset);
 		return -EINVAL;
 	}
 
-	/* Calculate & validate frame size based on slot info provided. */
-	frame_size = slots * slot_width;
-	switch (frame_size) {
-	case 32:
-		dai_bclks_per_wclk = DA7219_DAI_BCLKS_PER_WCLK_32;
-		break;
-	case 64:
-		dai_bclks_per_wclk = DA7219_DAI_BCLKS_PER_WCLK_64;
-		break;
-	case 128:
-		dai_bclks_per_wclk = DA7219_DAI_BCLKS_PER_WCLK_128;
-		break;
-	case 256:
-		dai_bclks_per_wclk = DA7219_DAI_BCLKS_PER_WCLK_256;
-		break;
-	default:
-		dev_err(component->dev, "Invalid frame size %d\n", frame_size);
-		return -EINVAL;
-	}
+	/*
+	 * If we're master, calculate & validate frame size based on slot info
+	 * provided as we have a limited set of rates available.
+	 */
+	if (da7219->master) {
+		frame_size = slots * slot_width;
+		switch (frame_size) {
+		case 32:
+			dai_bclks_per_wclk = DA7219_DAI_BCLKS_PER_WCLK_32;
+			break;
+		case 64:
+			dai_bclks_per_wclk = DA7219_DAI_BCLKS_PER_WCLK_64;
+			break;
+		case 128:
+			dai_bclks_per_wclk = DA7219_DAI_BCLKS_PER_WCLK_128;
+			break;
+		case 256:
+			dai_bclks_per_wclk = DA7219_DAI_BCLKS_PER_WCLK_256;
+			break;
+		default:
+			dev_err(component->dev, "Invalid frame size %d\n",
+				frame_size);
+			return -EINVAL;
+		}
 
-	snd_soc_component_update_bits(component, DA7219_DAI_CLK_MODE,
-			    DA7219_DAI_BCLKS_PER_WCLK_MASK,
-			    dai_bclks_per_wclk);
+		snd_soc_component_update_bits(component, DA7219_DAI_CLK_MODE,
+				DA7219_DAI_BCLKS_PER_WCLK_MASK,
+				dai_bclks_per_wclk);
+	}
 
-	offset = cpu_to_le16(rx_mask);
+	dai_offset = cpu_to_le16(offset);
 	regmap_bulk_write(da7219->regmap, DA7219_DAI_OFFSET_LOWER,
-			  &offset, sizeof(offset));
+			  &dai_offset, sizeof(dai_offset));
 
 	snd_soc_component_update_bits(component, DA7219_DAI_TDM_CTRL,
 			    DA7219_DAI_TDM_CH_EN_MASK |
 			    DA7219_DAI_TDM_MODE_EN_MASK,
-			    (tx_mask << DA7219_DAI_TDM_CH_EN_SHIFT) |
+			    (ch_mask << DA7219_DAI_TDM_CH_EN_SHIFT) |
 			    DA7219_DAI_TDM_MODE_EN_MASK);
 
 	da7219->tdm_en = true;
-- 
1.9.1

RE: [PATCH 0/2] ASoC: da7219: BCLK and TDM flexibility improvements

[Adam Thomson]

On 13 February 2019 17:48, Adam Thomson wrote:

 This patch set updates the driver to be more flexible regarding the BCLK and TDM
> configurations of the device.
> 
> Previously the BCLK rate was fixed at 64 periods per WCLK, when the codec is DAI
> clock master, but to satisfy devices which prefer a lower rate, and to save power,
> the BCLK rate is now calculated based on hw_params() data.
> 
> As a fallout of the BCLK efforts it was also apparent that the TDM code could be
> made more flexible as well. The device is capable of automatically detecting the
> BCLK rate when it is clock slave, so previous limitations imposed were not
> necessary. The mask handling is now used as an input to determine the BCLK
> offset to align closer with other examples within ALSA.

Spotted a silly '&' instead of '&&' error in the 1st patch. Functionally will work
but technically should be updated. Will send V2 soon.

> 
> Adam Thomson (2):
>   ASoC: da7219: Add support for master mode BCLK rate adjustment
>   ASoC: da7219: Update TDM usage to be more flexible
> 
>  sound/soc/codecs/da7219.c | 116 +++++++++++++++++++++++++++++----------
> -------
>  sound/soc/codecs/da7219.h |   1 +
>  2 files changed, 74 insertions(+), 43 deletions(-)
> 
> --
> 1.9.1