[PATCH 6/9] ASoC: mediatek: mt2701: add machine driver for on-chip HDMI codec

Daniel Golle
2026-04-15T15:24:15Z

Add a simple ASoC machine driver that wires the MT2701/MT7623N
AFE HDMI playback path to the on-chip HDMI transmitter exposed
as a generic hdmi-audio-codec "i2s-hifi" DAI.

The driver binds to "mediatek,mt2701-hdmi-audio". MT7623N device
trees carry "mediatek,mt7623n-hdmi-audio" as a board-specific
fallback, matching the dt-binding.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
sound/soc/mediatek/Kconfig | 10 +++
sound/soc/mediatek/mt2701/Makefile | 1 +
sound/soc/mediatek/mt2701/mt2701-hdmi.c | 114 ++++++++++++++++++++++++
3 files changed, 125 insertions(+)
create mode 100644 sound/soc/mediatek/mt2701/mt2701-hdmi.c

diff --git a/sound/soc/mediatek/Kconfig b/sound/soc/mediatek/Kconfig
index 3a1e1fa3fe5cc..fa076e7854adc 100644
--- a/sound/soc/mediatek/Kconfig
+++ b/sound/soc/mediatek/Kconfig
@@ -26,6 +26,16 @@ config SND_SOC_MT2701_CS42448
Select Y if you have such device.
If unsure select "N".

+config SND_SOC_MT2701_HDMI
+ tristate "ASoC Audio driver for MT2701 with on-chip HDMI codec"
+ depends on SND_SOC_MT2701
+ select SND_SOC_HDMI_CODEC
+ help
+ This adds the ASoC machine driver for MediaTek MT2701 and
+ MT7623N boards routing the AFE I2S back-end to the on-chip
+ HDMI transmitter via the generic HDMI codec.
+ If unsure select "N".
+
config SND_SOC_MT2701_WM8960
tristate "ASoc Audio driver for MT2701 with WM8960 codec"
depends on SND_SOC_MT2701 && I2C
diff --git a/sound/soc/mediatek/mt2701/Makefile b/sound/soc/mediatek/mt2701/Makefile
index 507fa26c39452..59623d3d3a038 100644
--- a/sound/soc/mediatek/mt2701/Makefile
+++ b/sound/soc/mediatek/mt2701/Makefile
@@ -5,4 +5,5 @@ obj-$(CONFIG_SND_SOC_MT2701) += snd-soc-mt2701-afe.o

# machine driver
obj-$(CONFIG_SND_SOC_MT2701_CS42448) += mt2701-cs42448.o
+obj-$(CONFIG_SND_SOC_MT2701_HDMI) += mt2701-hdmi.o
obj-$(CONFIG_SND_SOC_MT2701_WM8960) += mt2701-wm8960.o
diff --git a/sound/soc/mediatek/mt2701/mt2701-hdmi.c b/sound/soc/mediatek/mt2701/mt2701-hdmi.c
new file mode 100644
index 0000000000000..a84907879c04e
--- /dev/null
+++ b/sound/soc/mediatek/mt2701/mt2701-hdmi.c
@@ -0,0 +1,114 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * mt2701-hdmi.c -- MT2701 HDMI ALSA SoC machine driver
+ *
+ * Copyright (c) 2026 Daniel Golle <daniel@makrotopia.org>
+ *
+ * Based on mt2701-cs42448.c
+ */
+
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <sound/soc.h>
+
+enum {
+ DAI_LINK_FE_HDMI_OUT,
+ DAI_LINK_BE_HDMI_I2S,
+};
+
+SND_SOC_DAILINK_DEFS(fe_hdmi_out,
+ DAILINK_COMP_ARRAY(COMP_CPU("PCM_HDMI")),
+ DAILINK_COMP_ARRAY(COMP_DUMMY()),
+ DAILINK_COMP_ARRAY(COMP_EMPTY()));
+
+SND_SOC_DAILINK_DEFS(be_hdmi_i2s,
+ DAILINK_COMP_ARRAY(COMP_CPU("HDMI I2S")),
+ DAILINK_COMP_ARRAY(COMP_CODEC(NULL, "i2s-hifi")),
+ DAILINK_COMP_ARRAY(COMP_EMPTY()));
+
+static struct snd_soc_dai_link mt2701_hdmi_dai_links[] = {
+ [DAI_LINK_FE_HDMI_OUT] = {
+ .name = "HDMI Playback",
+ .stream_name = "HDMI Playback",
+ .trigger = { SND_SOC_DPCM_TRIGGER_POST,
+ SND_SOC_DPCM_TRIGGER_POST },
+ .dynamic = 1,
+ .playback_only = 1,
+ SND_SOC_DAILINK_REG(fe_hdmi_out),
+ },
+ [DAI_LINK_BE_HDMI_I2S] = {
+ .name = "HDMI BE",
+ .no_pcm = 1,
+ .playback_only = 1,
+ .dai_fmt = SND_SOC_DAIFMT_I2S | SND_SOC_DAIFMT_NB_NF |
+ SND_SOC_DAIFMT_CBC_CFC,
+ SND_SOC_DAILINK_REG(be_hdmi_i2s),
+ },
+};
+
+static struct snd_soc_card mt2701_hdmi_soc_card = {
+ .name = "mt2701-hdmi",
+ .owner = THIS_MODULE,
+ .dai_link = mt2701_hdmi_dai_links,
+ .num_links = ARRAY_SIZE(mt2701_hdmi_dai_links),
+};
+
+static int mt2701_hdmi_machine_probe(struct platform_device *pdev)
+{
+ struct snd_soc_card *card = &mt2701_hdmi_soc_card;
+ struct device *dev = &pdev->dev;
+ struct device_node *platform_node;
+ struct device_node *codec_node;
+ struct snd_soc_dai_link *dai_link;
+ int ret;
+ int i;
+
+ platform_node = of_parse_phandle(dev->of_node, "mediatek,platform", 0);
+ if (!platform_node)
+ return dev_err_probe(dev, -EINVAL,
+ "Property 'mediatek,platform' missing\n");
+
+ for_each_card_prelinks(card, i, dai_link) {
+ if (dai_link->platforms->name)
+ continue;
+ dai_link->platforms->of_node = platform_node;
+ }
+
+ codec_node = of_parse_phandle(dev->of_node, "mediatek,audio-codec", 0);
+ if (!codec_node) {
+ of_node_put(platform_node);
+ return dev_err_probe(dev, -EINVAL,
+ "Property 'mediatek,audio-codec' missing\n");
+ }
+ mt2701_hdmi_dai_links[DAI_LINK_BE_HDMI_I2S].codecs->of_node = codec_node;
+
+ card->dev = dev;
+
+ ret = devm_snd_soc_register_card(dev, card);
+
+ of_node_put(platform_node);
+ of_node_put(codec_node);
+ return ret;
+}
+
+static const struct of_device_id mt2701_hdmi_machine_dt_match[] = {
+ { .compatible = "mediatek,mt2701-hdmi-audio" },
+ { .compatible = "mediatek,mt7623n-hdmi-audio" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, mt2701_hdmi_machine_dt_match);
+
+static struct platform_driver mt2701_hdmi_machine = {
+ .driver = {
+ .name = "mt2701-hdmi",
+ .of_match_table = mt2701_hdmi_machine_dt_match,
+ },
+ .probe = mt2701_hdmi_machine_probe,
+};
+module_platform_driver(mt2701_hdmi_machine);
+
+MODULE_DESCRIPTION("MT2701 HDMI ALSA SoC machine driver");
+MODULE_AUTHOR("Daniel Golle <daniel@makrotopia.org>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:mt2701-hdmi");
--
2.53.0