4 files changed, 125 insertions, 0 deletions
diff --git a/src/drivers/generic/max98357a/Kconfig b/src/drivers/generic/max98357a/Kconfig
new file mode 100644
index 0000000000..a7104f19c2
--- /dev/null
+++ b/src/drivers/generic/max98357a/Kconfig
@@ -0,0 +1,2 @@
+config DRIVERS_GENERIC_MAX98357A
+	bool
diff --git a/src/drivers/generic/max98357a/Makefile.inc b/src/drivers/generic/max98357a/Makefile.inc
new file mode 100644
index 0000000000..529e24afc9
--- /dev/null
+++ b/src/drivers/generic/max98357a/Makefile.inc
@@ -0,0 +1 @@
+ramstage-$(CONFIG_DRIVERS_GENERIC_MAX98357A) += max98357a.c
diff --git a/src/drivers/generic/max98357a/chip.h b/src/drivers/generic/max98357a/chip.h
new file mode 100644
index 0000000000..0abd616c18
--- /dev/null
+++ b/src/drivers/generic/max98357a/chip.h
@@ -0,0 +1,13 @@
+#include <arch/acpi_device.h>
+
+struct drivers_generic_max98357a_config {
+	/* SDMODE GPIO */
+	struct acpi_gpio sdmode_gpio;
+
+	/* SDMODE Delay */
+	unsigned sdmode_delay;
+
+	/* GPIO used to indicate if this device is present */
+	unsigned device_present_gpio;
+	unsigned device_present_gpio_invert;
+};
diff --git a/src/drivers/generic/max98357a/max98357a.c b/src/drivers/generic/max98357a/max98357a.c
new file mode 100644
index 0000000000..cbd7efd7bd
--- /dev/null
+++ b/src/drivers/generic/max98357a/max98357a.c
@@ -0,0 +1,109 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2016 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <arch/acpi_device.h>
+#include <arch/acpigen.h>
+#include <console/console.h>
+#include <device/device.h>
+#include <device/path.h>
+#include <gpio.h>
+#include <stdint.h>
+#include <string.h>
+#include "chip.h"
+
+#if IS_ENABLED(CONFIG_HAVE_ACPI_TABLES)
+
+#define MAX98357A_ACPI_NAME	"MAXM"
+#define MAX98357A_ACPI_HID	"MX98357A"
+
+static void max98357a_fill_ssdt(struct device *dev)
+{
+	struct drivers_generic_max98357a_config *config = dev->chip_info;
+	const char *path = acpi_device_path(dev);
+
+	if (!dev->enabled || !path || !config)
+		return;
+
+	/* Device */
+	acpigen_write_scope(acpi_device_scope(dev));
+	acpigen_write_device(acpi_device_name(dev));
+	acpigen_write_name_string("_HID", MAX98357A_ACPI_HID);
+	acpigen_write_name_integer("_UID", 0);
+	acpigen_write_name_string("_DDN", dev->chip_ops->name);
+	acpigen_write_STA(ACPI_STATUS_DEVICE_ALL_ON);
+
+	/* Resources */
+	acpigen_write_name("_CRS");
+	acpigen_write_resourcetemplate_header();
+	acpi_device_write_gpio(&config->sdmode_gpio);
+	acpigen_write_resourcetemplate_footer();
+
+	/* _DSD for devicetree properties */
+	acpi_dp_write_header();
+	/* This points to the first pin in the first gpio entry in _CRS */
+	acpi_dp_write_gpio("maxim,sdmode-gpio", path, 0, 0, 0);
+	/* This is the correctly formatted Device Property name */
+	acpi_dp_write_integer("maxim,sdmode-delay", config->sdmode_delay);
+	/* This is used by the chromium kernel but is not upstream */
+	acpi_dp_write_integer("sdmode-delay", config->sdmode_delay);
+	acpi_dp_write_footer();
+
+	acpigen_pop_len(); /* Device */
+	acpigen_pop_len(); /* Scope */
+
+	printk(BIOS_INFO, "%s: %s\n", path, dev->chip_ops->name);
+}
+
+static const char *max98357a_acpi_name(struct device *dev)
+{
+	return MAX98357A_ACPI_NAME;
+}
+#endif
+
+static struct device_operations max98357a_ops = {
+	.read_resources		  = DEVICE_NOOP,
+	.set_resources		  = DEVICE_NOOP,
+	.enable_resources	  = DEVICE_NOOP,
+#if IS_ENABLED(CONFIG_HAVE_ACPI_TABLES)
+	.acpi_name                = &max98357a_acpi_name,
+	.acpi_fill_ssdt_generator = &max98357a_fill_ssdt,
+#endif
+};
+
+static void max98357a_enable(struct device *dev)
+{
+	struct drivers_generic_max98357a_config *config = dev->chip_info;
+
+	/* Check if device is present by reading GPIO */
+	if (config->device_present_gpio) {
+		int present = gpio_get(config->device_present_gpio);
+		present ^= config->device_present_gpio_invert;
+
+		printk(BIOS_INFO, "%s is %spresent\n",
+		       dev->chip_ops->name, present ? "" : "not ");
+
+		if (!present) {
+			dev->enabled = 0;
+			return;
+		}
+	}
+
+	dev->ops = &max98357a_ops;
+}
+
+struct chip_operations drivers_generic_max98357a_ops = {
+	CHIP_NAME("Maxim Integrated 98357A Amplifier")
+	.enable_dev = &max98357a_enable
+};