Change in coreboot[master]: WIP: generic: Add generic DMIC driver

[Sathyanarayana Nujella (Code Review)]

Hello Jairaj Arava, HARSHAPRIYA N,

I'd like you to do a code review. Please visit

https://review.coreboot.org/28778

to review the following change.

Change subject: WIP: generic: Add generic DMIC driver
......................................................................

WIP: generic: Add generic DMIC driver

DMIC driver in Kernel needs configurations like modeswitch_delay_ms
which is used to adust the minimum clock ON time, etc.

DMIC is not an I2S or I2C slave, so adding as a generic driver.

BUG=b:112888584
TEST=build coreboot and cross check DUT boots

Change-Id: Ic8c8be1aa04e8d35ad4827d81a37ee54c25dfc63
Signed-off-by: Sathyanarayana Nujella 
Signed-off-by: Jairaj Arava 
Signed-off-by: Harsha Priya 
---
A src/drivers/generic/dmic/Kconfig
A src/drivers/generic/dmic/Makefile.inc
A src/drivers/generic/dmic/chip.h
A src/drivers/generic/dmic/dmic.c
4 files changed, 97 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/78/28778/1

diff --git a/src/drivers/generic/dmic/Kconfig b/src/drivers/generic/dmic/Kconfig
new file mode 100644
index 0000000..5234eeb
--- /dev/null
+++ b/src/drivers/generic/dmic/Kconfig
@@ -0,0 +1,2 @@
+config DRIVERS_GENERIC_DMIC
+	bool
diff --git a/src/drivers/generic/dmic/Makefile.inc b/src/drivers/generic/dmic/Makefile.inc
new file mode 100644
index 0000000..52bb984
--- /dev/null
+++ b/src/drivers/generic/dmic/Makefile.inc
@@ -0,0 +1 @@
+ramstage-$(CONFIG_DRIVERS_GENERIC_DMIC) += dmic.c
diff --git a/src/drivers/generic/dmic/chip.h b/src/drivers/generic/dmic/chip.h
new file mode 100644
index 0000000..6cb19bd
--- /dev/null
+++ b/src/drivers/generic/dmic/chip.h
@@ -0,0 +1,11 @@
+#ifndef __DRIVERS_GENERIC_DMIC__
+#define __DRIVERS_GENERIC_DMIC__
+
+#include <arch/acpi_device.h>
+
+struct drivers_generic_dmic_config {
+	/* SDMODE Delay */
+	unsigned modeswitch_delay_ms;
+};
+
+#endif
diff --git a/src/drivers/generic/dmic/dmic.c b/src/drivers/generic/dmic/dmic.c
new file mode 100644
index 0000000..e90f475
--- /dev/null
+++ b/src/drivers/generic/dmic/dmic.c
@@ -0,0 +1,83 @@
+/*
+ * 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 DMIC_ACPI_NAME	"DMIC"
+#define DMIC_ACPI_HID	"DMIC"
+
+
+static void dmic_fill_ssdt(struct device *dev)
+{
+	struct drivers_generic_dmic_config *config = dev->chip_info;
+	const char *path;
+	struct acpi_dp *dp;
+	if (!config)
+		return;
+
+	/* Device */
+	acpigen_write_scope(acpi_device_scope(dev));
+	acpigen_write_device(acpi_device_name(dev));
+	acpigen_write_name_string("_HID", DMIC_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);
+
+	/* _DSD for devicetree properties */
+	/* This points to the first pin in the first gpio entry in _CRS */
+	path = acpi_device_path(dev);
+	dp = acpi_dp_new_table("_DSD");
+	acpi_dp_add_integer(dp, "modeswitch_delay_ms", config->modeswitch_delay_ms);
+	acpi_dp_write(dp);
+
+	acpigen_pop_len(); /* Device */
+	acpigen_pop_len(); /* Scope */
+}
+
+static const char *dmic_acpi_name(const struct device *dev)
+{
+	return DMIC_ACPI_NAME;
+}
+#endif
+
+static struct device_operations dmic_ops = {
+	.read_resources		  = DEVICE_NOOP,
+	.set_resources		  = DEVICE_NOOP,
+	.enable_resources	  = DEVICE_NOOP,
+#if IS_ENABLED(CONFIG_HAVE_ACPI_TABLES)
+	.acpi_name                = &dmic_acpi_name,
+	.acpi_fill_ssdt_generator = &dmic_fill_ssdt,
+#endif
+};
+
+static void dmic_enable(struct device *dev)
+{
+	dev->ops = &dmic_ops;
+}
+
+struct chip_operations drivers_generic_dmic_ops = {
+	CHIP_NAME("DMIC")
+	.enable_dev = &dmic_enable
+};