384k: Add support for 352k8 and 384k to ALSA ASoC pcm5102a codec driver

hifiberry-dac overlay is used by both their 1st gen 'B' PCM5102 boards
and the later gen DAC+ Light ES9023.
(As well as being used by several other third party ES9023 boards.)
The PCM5102a is most certainly 352k8/384k capable. The ES9023
datasheet states 192k PCM MAX, but we know that some (not all) chips
are 384k capable. (NB: OSC is the other factor. Datasheet requirement
is >= 192xFS. Most ES9023 DAC HAT manufacturers use 50MHz OSC.)
So we default to supporting 8k-192k MAX, unless dt param, '384k', is
specified via hifiberry-dac overlay and parsed by pcm5102a codec driver,
in which case, the 8k-384k constraint is used.
NB: Original plan, adding 384k support to pcm5102a codec, was to use
es9023 codec and hifiberry-dacpluslight overlay for HB DAC+ Light, but
HB would prefer to contine with their use of hifiberry_dac/pcm5102a
combo for DAC+ Light... "However, at the moment I would like to stick
with the PCM5102 driver with the DAC+ Light."

Signed-off-by: DigitalDreamtime <[email protected]>

Author: DigitalDreamtime

arch/arm/boot/dts/overlays/README

@@ -343,8 +343,9 @@ Params: <None>
 
 Name:   hifiberry-dac
 Info:   Configures the HifiBerry DAC audio card
-Load:   dtoverlay=hifiberry-dac
-Params: <None>
+Load:   dtoverlay=hifiberry-dac,<param>
+Params: 384k                    Instructs the pcm5102a codec driver to support
+                                352k8 and 384k sample rates.
 
 
 Name:   hifiberry-dacplus

arch/arm/boot/dts/overlays/hifiberry-dac-overlay.dts

@@ -15,7 +15,7 @@
 	fragment@1 {
 		target-path = "/";
 		__overlay__ {
-			pcm5102a-codec {
+			pcm5102a: pcm5102a-codec {
 				#sound-dai-cells = <0>;
 				compatible = "ti,pcm5102a";
 				status = "okay";
@@ -31,4 +31,8 @@
 			status = "okay";
 		};
 	};
+
+	__overrides__ {
+		384k = <&pcm5102a>,"pcm5102a,384k?";
+	};
 };

sound/soc/codecs/pcm5102a.c

@@ -21,22 +21,73 @@
 
 #include <sound/soc.h>
 
+static bool rates_384k = false;
+
+static const u32 pcm5102a_dai_rates_192k[] = {
+	8000, 11025, 16000, 22050, 32000, 44100, 48000, 64000, 88200, 96000,
+	176400, 192000,
+};
+
+static const struct snd_pcm_hw_constraint_list constraints_rates_192k = {
+	.list  = pcm5102a_dai_rates_192k,
+	.count = ARRAY_SIZE(pcm5102a_dai_rates_192k),
+};
+
+static const u32 pcm5102a_dai_rates_384k[] = {
+	8000, 11025, 16000, 22050, 32000, 44100, 48000, 64000, 88200, 96000,
+	176400, 192000, 352800, 384000,
+};
+
+static const struct snd_pcm_hw_constraint_list constraints_rates_384k = {
+	.list  = pcm5102a_dai_rates_384k,
+	.count = ARRAY_SIZE(pcm5102a_dai_rates_384k),
+};
+
+static int pcm5102a_dai_startup(struct snd_pcm_substream *substream,
+	struct snd_soc_dai *dai)
+{
+	struct snd_soc_codec *codec = dai->codec;
+	int ret;
+
+	dev_dbg(codec->dev, "%s: setup rates (%s) constraint.\n", __func__,
+		(rates_384k ? "8k-384k" : "8k-192k"));
+
+	ret = snd_pcm_hw_constraint_list(substream->runtime, 0,
+					 SNDRV_PCM_HW_PARAM_RATE,
+					 (rates_384k ? &constraints_rates_384k
+						: &constraints_rates_192k));
+	if (ret != 0)
+                dev_err(codec->dev, "%s: Failed to set rates constraint: %d!\n",
+			__func__, ret);
+
+	return ret;
+}
+
+static const struct snd_soc_dai_ops pcm5102a_dai_ops = {
+	.startup = pcm5102a_dai_startup,
+};
+
 static struct snd_soc_dai_driver pcm5102a_dai = {
 	.name = "pcm5102a-hifi",
 	.playback = {
 		.channels_min = 2,
 		.channels_max = 2,
-		.rates = SNDRV_PCM_RATE_8000_192000,
+		.rates = SNDRV_PCM_RATE_KNOT,
 		.formats = SNDRV_PCM_FMTBIT_S16_LE |
 			   SNDRV_PCM_FMTBIT_S24_LE |
 			   SNDRV_PCM_FMTBIT_S32_LE
 	},
+	.ops = &pcm5102a_dai_ops,
 };
 
 static struct snd_soc_codec_driver soc_codec_dev_pcm5102a;
 
 static int pcm5102a_probe(struct platform_device *pdev)
 {
+	if (pdev->dev.of_node)
+		rates_384k = of_property_read_bool(pdev->dev.of_node,
+						   "pcm5102a,384k");
+
 	return snd_soc_register_codec(&pdev->dev, &soc_codec_dev_pcm5102a,
 			&pcm5102a_dai, 1);
 }