ASoC: adds ADC8x support to the Hifiberry DAC8x

The driver probes for the ADC8x which can be stacked on top
of the DAC8x. It enables a symmetric 8 channel capture using
the dummy-dai.

Signed-off-by: j-schambacher <joerg@hifiberry.com>

Author: j-schambacher

sound/soc/bcm/rpi-simple-soundcard.c

@@ -354,16 +354,46 @@ static struct snd_rpi_simple_drvdata drvdata_hifiberry_dac = {
 	.dai       = snd_hifiberry_dac_dai,
 };
 
+SND_SOC_DAILINK_DEFS(hifiberry_dac8x,
+	DAILINK_COMP_ARRAY(COMP_EMPTY()),
+	DAILINK_COMP_ARRAY(COMP_CODEC("snd-soc-dummy", "snd-soc-dummy-dai")),
+	DAILINK_COMP_ARRAY(COMP_EMPTY()));
+
 static int hifiberry_dac8x_init(struct snd_soc_pcm_runtime *rtd)
 {
 	struct snd_soc_dai *codec_dai = snd_soc_rtd_to_codec(rtd, 0);
+	struct snd_soc_card *card = rtd->card;
+	struct gpio_desc *gpio_desc;
+	bool has_adc;
 
-	/* override the defaults to reflect 4 x PCM5102A on the card
-	 * and limit the sample rate to 192ksps
-	 */
+	/* Configure the codec for 8 channel playback */
 	codec_dai->driver->playback.channels_max = 8;
 	codec_dai->driver->playback.rates = SNDRV_PCM_RATE_8000_192000;
 
+	/* Activate capture based on ADC8x detection */
+	gpio_desc = devm_gpiod_get(card->dev, "hasadc", GPIOD_IN);
+	if (IS_ERR(gpio_desc)) {
+		dev_err(card->dev, "Failed to get GPIO: %ld\n", PTR_ERR(gpio_desc));
+		return PTR_ERR(gpio_desc);
+	}
+
+	has_adc = gpiod_get_value(gpio_desc);
+
+	if (has_adc) {
+		struct snd_soc_dai_link *dai = rtd->dai_link;
+
+		dev_info(card->dev, "ADC8x detected: capture enabled\n");
+		codec_dai->driver->symmetric_rate = 1;
+		codec_dai->driver->symmetric_channels = 1;
+		codec_dai->driver->symmetric_sample_bits = 1;
+		codec_dai->driver->capture.rates = SNDRV_PCM_RATE_8000_192000;
+		dai->name = "HiFiBerry DAC8xADC8x";
+		dai->stream_name = "HiFiBerry DAC8xADC8x HiFi";
+	} else {
+		dev_info(card->dev, "no ADC8x detected\n");
+		rtd->dai_link->playback_only = 1;  // Disable capture
+	}
+
 	return 0;
 }
 
@@ -375,7 +405,7 @@ static struct snd_soc_dai_link snd_hifiberry_dac8x_dai[] = {
 					SND_SOC_DAIFMT_NB_NF |
 					SND_SOC_DAIFMT_CBS_CFS,
 		.init           = hifiberry_dac8x_init,
-		SND_SOC_DAILINK_REG(hifiberry_dac),
+		SND_SOC_DAILINK_REG(hifiberry_dac8x),
 	},
 };