[PATCH RFC 3/9] ASoC: davinci-evm: HDMI audio support for TDA998x trough McASP I2S bus

[Jyri Sarha <jsarha@ti.com>]

Add machine driver support for BeagleBone-Black and other boards with
tilcdc support and NXP TDA998X HDMI transmitter connected to McASP
port in I2S mode. The 44100 Hz sample-rate and it's multiples can not
be supported on Beaglebone-Black because of limited clock-rate
support. The only supported sample format is SNDRV_PCM_FORMAT_S32_LE.
The 8 least significant bits are ignored.

Signed-off-by: Jyri Sarha <jsarha@ti.com>
---
 .../bindings/sound/davinci-evm-audio.txt           |    3 +-
 sound/soc/davinci/davinci-evm.c                    |  167 +++++++++++++++++++-
 2 files changed, 167 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/sound/davinci-evm-audio.txt b/Documentation/devicetree/bindings/sound/davinci-evm-audio.txt
index 4aa00f6..2abc4c2 100644
--- a/Documentation/devicetree/bindings/sound/davinci-evm-audio.txt
+++ b/Documentation/devicetree/bindings/sound/davinci-evm-audio.txt
@@ -1,7 +1,8 @@
 * Texas Instruments SoC audio setups with TLV320AIC3X Codec
 
 Required properties:
-- compatible : "ti,da830-evm-audio" : forDM365/DA8xx/OMAPL1x/AM33xx
+- compatible : "ti,da830-evm-audio" : for DM365/DA8xx/OMAPL1x/AM33xx
+               "ti,am33xx-beaglebone-black" : for Beaglebone-black HDMI audio
 - ti,model : The user-visible name of this sound complex.
 - ti,audio-codec : The phandle of the TLV320AIC3x audio codec
 - ti,mcasp-controller : The phandle of the McASP controller
diff --git a/sound/soc/davinci/davinci-evm.c b/sound/soc/davinci/davinci-evm.c
index b28c9fd..71496b6 100644
--- a/sound/soc/davinci/davinci-evm.c
+++ b/sound/soc/davinci/davinci-evm.c
@@ -21,6 +21,7 @@
 #include <sound/core.h>
 #include <sound/pcm.h>
 #include <sound/soc.h>
+#include <sound/pcm_params.h>
 
 #include <asm/dma.h>
 #include <asm/mach-types.h>
@@ -33,8 +34,13 @@
 struct snd_soc_card_drvdata_davinci {
 	struct clk *mclk;
 	unsigned sysclk;
+	struct snd_pcm_hw_constraint_list *rate_constraint;
 };
 
+/* If changing sample format the tda998x configuration (REG_CTS_N) needs
+   to be changed. */
+#define TDA998X_SAMPLE_FORMAT SNDRV_PCM_FORMAT_S32_LE
+
 static int evm_startup(struct snd_pcm_substream *substream)
 {
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
@@ -80,12 +86,80 @@ static int evm_hw_params(struct snd_pcm_substream *substream,
 	return 0;
 }
 
+static int evm_tda998x_startup(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct snd_soc_card *soc_card = rtd->codec->card;
+	struct snd_soc_card_drvdata_davinci *drvdata =
+		(struct snd_soc_card_drvdata_davinci *)
+		snd_soc_card_get_drvdata(soc_card);
+	struct snd_mask *fmt = constrs_mask(&runtime->hw_constraints,
+					    SNDRV_PCM_HW_PARAM_FORMAT);
+	snd_mask_none(fmt);
+	snd_mask_set(fmt, TDA998X_SAMPLE_FORMAT);
+
+	runtime->hw.rate_min = drvdata->rate_constraint->list[0];
+	runtime->hw.rate_max = drvdata->rate_constraint->list[
+		drvdata->rate_constraint->count - 1];
+	runtime->hw.rates = SNDRV_PCM_RATE_KNOT;
+
+	snd_pcm_hw_constraint_list(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
+				   drvdata->rate_constraint);
+	snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_CHANNELS,
+				     2, 2);
+
+	return evm_startup(substream);
+}
+
+static unsigned int evm_get_bclk(struct snd_pcm_hw_params *params)
+{
+	int sample_size = snd_pcm_format_width(params_format(params));
+	int rate = params_rate(params);
+	int channels = params_channels(params);
+
+	return sample_size * channels * rate;
+}
+
+static int evm_tda998x_hw_params(struct snd_pcm_substream *substream,
+				 struct snd_pcm_hw_params *params)
+{
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct snd_soc_dai *cpu_dai = rtd->cpu_dai;
+	struct snd_soc_codec *codec = rtd->codec;
+	struct snd_soc_card *soc_card = codec->card;
+	struct platform_device *pdev = to_platform_device(soc_card->dev);
+	unsigned int bclk_freq = evm_get_bclk(params);
+	unsigned sysclk = ((struct snd_soc_card_drvdata_davinci *)
+			   snd_soc_card_get_drvdata(soc_card))->sysclk;
+	int ret;
+
+	ret = snd_soc_dai_set_clkdiv(cpu_dai, 1, sysclk / bclk_freq);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "can't set CPU DAI clock divider %d\n",
+			ret);
+		return ret;
+	}
+
+	ret = snd_soc_dai_set_sysclk(cpu_dai, 0, sysclk, SND_SOC_CLOCK_IN);
+	if (ret < 0)
+		return ret;
+
+	return ret;
+}
+
 static struct snd_soc_ops evm_ops = {
 	.startup = evm_startup,
 	.shutdown = evm_shutdown,
 	.hw_params = evm_hw_params,
 };
 
+static struct snd_soc_ops evm_tda998x_ops = {
+	.startup = evm_tda998x_startup,
+	.shutdown = evm_shutdown,
+	.hw_params = evm_tda998x_hw_params,
+};
+
 /* davinci-evm machine dapm widgets */
 static const struct snd_soc_dapm_widget aic3x_dapm_widgets[] = {
 	SND_SOC_DAPM_HP("Headphone Jack", NULL),
@@ -152,6 +226,81 @@ static int evm_aic3x_init(struct snd_soc_pcm_runtime *rtd)
 	return 0;
 }
 
+static unsigned int tda998x_hdmi_rates[] = {
+	32000,
+	44100,
+	48000,
+	88200,
+	96000,
+};
+
+static struct snd_pcm_hw_constraint_list *evm_tda998x_rate_constraint(
+	struct snd_soc_card *soc_card)
+{
+	struct platform_device *pdev = to_platform_device(soc_card->dev);
+	unsigned sysclk = ((struct snd_soc_card_drvdata_davinci *)
+			   snd_soc_card_get_drvdata(soc_card))->sysclk;
+	struct snd_pcm_hw_constraint_list *ret;
+	unsigned int *rates;
+	int i = 0, j = 0;
+
+	ret = devm_kzalloc(soc_card->dev, sizeof(*ret) +
+			   sizeof(tda998x_hdmi_rates), GFP_KERNEL);
+	if (!ret) {
+		dev_err(&pdev->dev, "Unable to allocate rate constraint!\n");
+		return NULL;
+	}
+
+	rates = (unsigned int *)&ret[1];
+	ret->list = rates;
+	ret->mask = 0;
+	for (; i < ARRAY_SIZE(tda998x_hdmi_rates); i++) {
+		unsigned int bclk_freq = tda998x_hdmi_rates[i] * 2 *
+			snd_pcm_format_width(TDA998X_SAMPLE_FORMAT);
+		if (sysclk % bclk_freq == 0) {
+			rates[j++] = tda998x_hdmi_rates[i];
+			dev_dbg(soc_card->dev, "Allowing rate %u\n",
+				tda998x_hdmi_rates[i]);
+		}
+	}
+	ret->count = j;
+	return ret;
+}
+
+static const struct snd_soc_dapm_widget tda998x_dapm_widgets[] = {
+	SND_SOC_DAPM_OUTPUT("HDMI Out"),
+};
+
+static int evm_tda998x_init(struct snd_soc_pcm_runtime *rtd)
+{
+	struct snd_soc_dai *cpu_dai = rtd->cpu_dai;
+	struct snd_soc_dapm_context *dapm = &rtd->codec->dapm;
+	struct snd_soc_card *soc_card = rtd->codec->card;
+	struct snd_soc_card_drvdata_davinci *drvdata =
+		(struct snd_soc_card_drvdata_davinci *)
+		snd_soc_card_get_drvdata(soc_card);
+	int ret;
+
+	ret = snd_soc_dai_set_clkdiv(cpu_dai, 0, 1);
+	if (ret < 0)
+		return ret;
+
+	drvdata->rate_constraint = evm_tda998x_rate_constraint(soc_card);
+
+	snd_soc_dapm_new_controls(dapm, tda998x_dapm_widgets,
+				  ARRAY_SIZE(tda998x_dapm_widgets));
+
+	ret = snd_soc_of_parse_audio_routing(soc_card, "ti,audio-routing");
+
+	/* not connected */
+	snd_soc_dapm_disable_pin(dapm, "RX");
+
+	/* always connected */
+	snd_soc_dapm_enable_pin(dapm, "HDMI Out");
+
+	return 0;
+}
+
 /* davinci-evm digital audio interface glue - connects codec <--> CPU */
 static struct snd_soc_dai_link dm6446_evm_dai = {
 	.name = "TLV320AIC3X",
@@ -337,7 +486,7 @@ static struct snd_soc_card da850_snd_soc_card = {
 #if defined(CONFIG_OF)
 
 /*
- * The struct is used as place holder. It will be completely
+ * The structs are used as place holders. They will be completely
  * filled with data from dt node.
  */
 static struct snd_soc_dai_link evm_dai_tlv320aic3x = {
@@ -350,10 +499,24 @@ static struct snd_soc_dai_link evm_dai_tlv320aic3x = {
 		   SND_SOC_DAIFMT_IB_NF,
 };
 
+static struct snd_soc_dai_link evm_dai_tda998x_hdmi = {
+	.name		= "NXP TDA998x HDMI Chip",
+	.stream_name	= "HDMI",
+	.codec_dai_name	= "hdmi-hifi",
+	.ops		= &evm_tda998x_ops,
+	.init           = evm_tda998x_init,
+	.dai_fmt	= (SND_SOC_DAIFMT_CBS_CFS | SND_SOC_DAIFMT_I2S |
+			   SND_SOC_DAIFMT_IB_NF),
+};
+
 static const struct of_device_id davinci_evm_dt_ids[] = {
 	{
 		.compatible = "ti,da830-evm-audio",
-		.data = (void *) &evm_dai_tlv320aic3x,
+		.data = &evm_dai_tlv320aic3x,
+	},
+	{
+		.compatible = "ti,am33xx-beaglebone-black",
+		.data = &evm_dai_tda998x_hdmi,
 	},
 	{ /* sentinel */ }
 };
-- 
1.7.9.5