ASoC: amd: Add support for enabling DMIC on acp6x via _DSD

Currently the acp6x machine driver requires a hardcoded list of systems
that physically have DMIC connected.

To avoid having to continually add to an evergrowing list of systems add
support for a _DSD that can advertise this.

OEMs can add this _DSD to their BIOS under the ACP device to automatically
add the device to this driver without requiring any driver modifications.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20220411134532.13538-3-mario.limonciello@amd.com
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/amd/yc/acp6x-mach.c

@@ -12,6 +12,7 @@
 #include <sound/pcm_params.h>
 #include <linux/io.h>
 #include <linux/dmi.h>
+#include <linux/acpi.h>
 
 #include "acp6x.h"
 
@@ -178,8 +179,19 @@ static int acp6x_probe(struct platform_device *pdev)
 	const struct dmi_system_id *dmi_id;
 	struct acp6x_pdm *machine = NULL;
 	struct snd_soc_card *card;
+	struct acpi_device *adev;
 	int ret;
 
+	/* check the parent device's firmware node has _DSD or not */
+	adev = ACPI_COMPANION(pdev->dev.parent);
+	if (adev) {
+		const union acpi_object *obj;
+
+		if (!acpi_dev_get_property(adev, "AcpDmicConnected", ACPI_TYPE_INTEGER, &obj) &&
+		    obj->integer.value == 1)
+			platform_set_drvdata(pdev, &acp6x_card);
+	}
+
 	/* check for any DMI overrides */
 	dmi_id = dmi_first_match(yc_acp_quirk_table);
 	if (dmi_id)
@@ -188,6 +200,7 @@ static int acp6x_probe(struct platform_device *pdev)
 	card = platform_get_drvdata(pdev);
 	if (!card)
 		return -ENODEV;
+	dev_info(&pdev->dev, "Enabling ACP DMIC support via %s", dmi_id ? "DMI" : "ACPI");
 	acp6x_card.dev = &pdev->dev;
 
 	snd_soc_card_set_drvdata(card, machine);