ASoC: adds support for AMP4 Pro to the DAC Plus driver

The AMP4 Pro is a I2S master mode capable amplifier with
clean onboard clock generators.
We can share the card driver between TAS575x amplifiers
and the PCM512x DACs as they are SW compatible.
From a HW perspective though we need to limit the sample
rates to the standard audio rates to avoid running the
onboard clocks through the PLL. Using the PLL would require
even a different HW.
DAI/stream name are also set accordingly to allow the user
a convenient identification of the soundcard

Needs the pcm512x driver with TAS575x support (already in
upstream kernel).

Signed-off-by: Joerg Schambacher <[email protected]>

Author: j-schambacher

sound/soc/bcm/hifiberry_dacplus.c

@@ -58,10 +58,21 @@ static bool leds_off;
 static bool auto_mute;
 static int mute_ext_ctl;
 static int mute_ext;
+static bool tas_device;
 static struct gpio_desc *snd_mute_gpio;
 static struct gpio_desc *snd_reset_gpio;
 static struct snd_soc_card snd_rpi_hifiberry_dacplus;
 
+static const u32 master_dai_rates[] = {
+	44100, 48000, 88200, 96000,
+	176400, 192000, 352800, 384000,
+};
+
+static const struct snd_pcm_hw_constraint_list constraints_master = {
+	.count = ARRAY_SIZE(master_dai_rates),
+	.list  = master_dai_rates,
+};
+
 static int snd_rpi_hifiberry_dacplus_mute_set(int mute)
 {
 	gpiod_set_value_cansleep(snd_mute_gpio, mute);
@@ -197,8 +208,13 @@ static int snd_rpi_hifiberry_dacplus_init(struct snd_soc_pcm_runtime *rtd)
 	if (snd_rpi_hifiberry_is_dacpro) {
 		struct snd_soc_dai_link *dai = rtd->dai_link;
 
-		dai->name = "HiFiBerry DAC+ Pro";
-		dai->stream_name = "HiFiBerry DAC+ Pro HiFi";
+		if (tas_device) {
+			dai->name = "HiFiBerry AMP4 Pro";
+			dai->stream_name = "HiFiBerry AMP4 Pro HiFi";
+		} else {
+			dai->name = "HiFiBerry DAC+ Pro";
+			dai->stream_name = "HiFiBerry DAC+ Pro HiFi";
+		}
 		dai->dai_fmt = SND_SOC_DAIFMT_I2S | SND_SOC_DAIFMT_NB_NF
 			| SND_SOC_DAIFMT_CBM_CFM;
 
@@ -303,6 +319,18 @@ static int snd_rpi_hifiberry_dacplus_startup(
 {
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct snd_soc_component *component = asoc_rtd_to_codec(rtd, 0)->component;
+	int ret;
+
+	if (tas_device && !slave) {
+		ret = snd_pcm_hw_constraint_list(substream->runtime, 0,
+					  SNDRV_PCM_HW_PARAM_RATE,
+					  &constraints_master);
+		if (ret < 0) {
+			dev_err(rtd->card->dev,
+				"Cannot apply constraints for sample rates\n");
+			return ret;
+		}
+	}
 
 	if (auto_mute)
 		gpiod_set_value_cansleep(snd_mute_gpio, 0);
@@ -324,7 +352,7 @@ static void snd_rpi_hifiberry_dacplus_shutdown(
 }
 
 /* machine stream operations */
-static struct snd_soc_ops snd_rpi_hifiberry_dacplus_ops = {
+static const struct snd_soc_ops snd_rpi_hifiberry_dacplus_ops = {
 	.hw_params = snd_rpi_hifiberry_dacplus_hw_params,
 	.startup = snd_rpi_hifiberry_dacplus_startup,
 	.shutdown = snd_rpi_hifiberry_dacplus_shutdown,
@@ -394,6 +422,7 @@ static int snd_rpi_hifiberry_dacplus_probe(struct platform_device *pdev)
 	struct snd_soc_card *card = &snd_rpi_hifiberry_dacplus;
 	int len;
 	struct device_node *tpa_node;
+	struct device_node *tas_node;
 	struct property *tpa_prop;
 	struct of_changeset ocs;
 	struct property *pp;
@@ -430,6 +459,12 @@ static int snd_rpi_hifiberry_dacplus_probe(struct platform_device *pdev)
 		}
 	}
 
+	tas_node = of_find_compatible_node(NULL, NULL, "ti,tas5756");
+	if (tas_node) {
+		tas_device = true;
+		dev_info(&pdev->dev, "TAS5756 device found!\n");
+	};
+
 	snd_rpi_hifiberry_dacplus.dev = &pdev->dev;
 	if (pdev->dev.of_node) {
 		struct device_node *i2s_node;