4 files changed, 115 insertions, 0 deletions
diff --git a/src/drivers/amd/i2s_machine_dev/Kconfig b/src/drivers/amd/i2s_machine_dev/Kconfig
new file mode 100644
index 0000000000..c9dabf7b82
--- /dev/null
+++ b/src/drivers/amd/i2s_machine_dev/Kconfig
@@ -0,0 +1,3 @@
+config DRIVERS_AMD_I2S_MACHINE_DEV
+	bool
+	depends on HAVE_ACPI_TABLES
diff --git a/src/drivers/amd/i2s_machine_dev/Makefile.inc b/src/drivers/amd/i2s_machine_dev/Makefile.inc
new file mode 100644
index 0000000000..df09f4d016
--- /dev/null
+++ b/src/drivers/amd/i2s_machine_dev/Makefile.inc
@@ -0,0 +1 @@
+ramstage-$(CONFIG_DRIVERS_AMD_I2S_MACHINE_DEV) += i2s_machine_dev.c
diff --git a/src/drivers/amd/i2s_machine_dev/chip.h b/src/drivers/amd/i2s_machine_dev/chip.h
new file mode 100644
index 0000000000..5d3a423b43
--- /dev/null
+++ b/src/drivers/amd/i2s_machine_dev/chip.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef __DRIVERS_AMD_I2S_MACHINE_DEV_H__
+#define __DRIVERS_AMD_I2S_MACHINE_DEV_H__
+
+#include <acpi/acpi_device.h>
+
+struct drivers_amd_i2s_machine_dev_config {
+	 /* ACPI _HID (required) */
+	const char *hid;
+
+	/* ACPI _UID */
+	unsigned int uid;
+
+	/* DMIC select GPIO (required) */
+	struct acpi_gpio dmic_select_gpio;
+};
+
+#endif /* ___DRIVERS_AMD_I2S_MACHINE_DEV_H__ */
diff --git a/src/drivers/amd/i2s_machine_dev/i2s_machine_dev.c b/src/drivers/amd/i2s_machine_dev/i2s_machine_dev.c
new file mode 100644
index 0000000000..a93826551d
--- /dev/null
+++ b/src/drivers/amd/i2s_machine_dev/i2s_machine_dev.c
@@ -0,0 +1,92 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <acpi/acpi_device.h>
+#include <acpi/acpigen.h>
+#include <device/device.h>
+#include <string.h>
+#include "chip.h"
+#include <console/console.h>
+
+#define AMD_I2S_ACPI_DESC	"I2S machine driver"
+
+static void i2s_machine_dev_fill_ssdt(const struct device *dev)
+{
+	const char *scope = acpi_device_scope(dev);
+	struct acpi_dp *dsd;
+	const struct acpi_gpio *dmic_select_gpio;
+	const struct drivers_amd_i2s_machine_dev_config *cfg;
+	const char *path = acpi_device_path(dev);
+
+	cfg = config_of(dev);
+
+	dmic_select_gpio = &cfg->dmic_select_gpio;
+
+	if (cfg->hid == NULL) {
+		printk(BIOS_ERR, "%s: ERROR: HID required\n", dev_path(dev));
+		return;
+	}
+
+	if (dmic_select_gpio->pin_count == 0) {
+		printk(BIOS_ERR, "%s: ERROR: DMIC select GPIO required\n", dev_path(dev));
+		return;
+	}
+
+	acpigen_write_scope(scope); /* Scope */
+	acpigen_write_device(acpi_device_name(dev)); /* Device */
+	acpigen_write_name_string("_HID", cfg->hid);
+	acpigen_write_name_integer("_UID", cfg->uid);
+	acpigen_write_name_string("_DDN", AMD_I2S_ACPI_DESC);
+
+	acpigen_write_STA(acpi_device_status(dev));
+
+	/* Resources */
+	acpigen_write_name("_CRS");
+	acpigen_write_resourcetemplate_header();
+	acpi_device_write_gpio(dmic_select_gpio);
+	acpigen_write_resourcetemplate_footer();
+
+	dsd = acpi_dp_new_table("_DSD");
+	/*
+	 * This GPIO is used to select DMIC0 or DMIC1 by the kernel driver. It does not
+	 * really have a polarity since low and high control the selection of DMIC and
+	 * hence does not have an active polarity.
+	 * Kernel driver does not use the polarity field and instead treats the GPIO
+	 * selection as follows:
+	 * Set low (0) = Select DMIC0
+	 * Set high (1) = Select DMIC1
+	 */
+	acpi_dp_add_gpio(dsd, "dmic-gpios", path,
+			 0,  /* Index = 0 (There is a single GPIO entry in _CRS). */
+			 0,  /* Pin = 0 (There is a single pin in the GPIO resource). */
+			 0); /* Active low = 0 (Kernel driver does not use active polarity). */
+	acpi_dp_write(dsd);
+
+	acpigen_pop_len(); /* Device */
+	acpigen_pop_len(); /* Scope */
+
+	printk(BIOS_INFO, "%s: %s at %s\n", path, AMD_I2S_ACPI_DESC, dev_path(dev));
+}
+
+static const char *i2s_machine_dev_acpi_name(const struct device *dev)
+{
+	static char name[5];
+	snprintf(name, sizeof(name), "I2S%X", dev->path.generic.id);
+	return name;
+}
+
+static struct device_operations i2s_machine_dev_ops = {
+	.read_resources		= noop_read_resources,
+	.set_resources		= noop_set_resources,
+	.acpi_name		= i2s_machine_dev_acpi_name,
+	.acpi_fill_ssdt		= i2s_machine_dev_fill_ssdt,
+};
+
+static void i2s_machine_dev_enable(struct device *dev)
+{
+	dev->ops = &i2s_machine_dev_ops;
+}
+
+struct chip_operations drivers_amd_i2s_machine_dev_ops = {
+	CHIP_NAME("AMD I2S Machine Device")
+	.enable_dev = i2s_machine_dev_enable
+};