drivers/gpio_keys: Add driver for handling gpio-keys

This change adds the required device node in SSDT for defining
gpio-keys/gpio-keys-polled. Currently, it supports only one gpio-key
per device node.

BUG=b:71329519
TEST=Verified by adding details to devicetree that device node is
added to SSDT:
        Device (PENH)
        {
            Name (_HID, "PRP0001")  // _HID: Hardware ID
            Name (_CRS, ResourceTemplate ()  // _CRS: Current Resource Settings
            {
                GpioIo (Exclusive, PullDefault, 0x0000, 0x0000, IoRestrictionInputOnly,
                    "\\_SB.PCI0.GPIO", 0x00, ResourceConsumer, ,
                    )
                    {   // Pin list
                        0x002B
                    }
            })
            Name (_DSD, Package (0x04)  // _DSD: Device-Specific Data
            {
                ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301") /* Device Properties for _DSD */,
                Package (0x01)
                {
                    Package (0x02)
                    {
                        "compatible",
                        "gpio-keys"
                    }
                },

                ToUUID ("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
                Package (0x01)
                {
                    Package (0x02)
                    {
                        "button-0",
                        "EJCT"
                    }
                }
            })
            Name (EJCT, Package (0x02)
            {
                ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301") /* Device Properties for _DSD */,
                Package (0x04)
                {
                    Package (0x02)
                    {
                        "linux,code",
                        0x0F
                    },

                    Package (0x02)
                    {
                        "linux,input-type",
                        0x05
                    },

                    Package (0x02)
                    {
                        "label",
                        "pen_eject"
                    },

                    Package (0x02)
                    {
                        "gpios",
                        Package (0x04)
                        {
                            \_SB.PCI0.I2C0.PENH,
                            Zero,
                            Zero,
                            One
                        }
                    }
                }
            })
        }

Change-Id: I6f11397b17d9de1c87d56f6a61669ef4052ec27b
Signed-off-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://review.coreboot.org/23236
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

4 files changed, 200 insertions, 0 deletions

diff --git a/src/drivers/generic/gpio_keys/Kconfig b/src/drivers/generic/gpio_keys/Kconfig
new file mode 100644
index 0000000000..fa073fb2d5
--- /dev/null
+++ b/src/drivers/generic/gpio_keys/Kconfig
@@ -0,0 +1,3 @@
+config DRIVERS_GENERIC_GPIO_KEYS
+	bool
+	depends on HAVE_ACPI_TABLES
diff --git a/src/drivers/generic/gpio_keys/Makefile.inc b/src/drivers/generic/gpio_keys/Makefile.inc
new file mode 100644
index 0000000000..1e10ca99e0
--- /dev/null
+++ b/src/drivers/generic/gpio_keys/Makefile.inc
@@ -0,0 +1 @@
+ramstage-$(CONFIG_DRIVERS_GENERIC_GPIO_KEYS) += gpio_keys.c
diff --git a/src/drivers/generic/gpio_keys/chip.h b/src/drivers/generic/gpio_keys/chip.h
new file mode 100644
index 0000000000..bdeb0afeb7
--- /dev/null
+++ b/src/drivers/generic/gpio_keys/chip.h
@@ -0,0 +1,67 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2018 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.
+ */
+
+#ifndef __DRIVERS_GENERIC_GPIO_KEYS_H__
+#define __DRIVERS_GENERIC_GPIO_KEYS_H__
+
+#include <arch/acpi_device.h>
+#include <stdint.h>
+
+/* Linux input type */
+enum {
+	/* Switch event */
+	EV_SW = 0x5,
+};
+
+/* Switch events type (Linux code emitted for EV_SW) */
+enum {
+	SW_PEN_INSERTED = 0xf,
+};
+
+/* Details of the child node defining key */
+struct key_info {
+	/* Device name of the child node - Mandatory */
+	const char *dev_name;
+	/* Keycode emitted for this key - Mandatory */
+	uint32_t linux_code;
+	/*
+	 * Event type generated for this key
+	 * See EV_* above.
+	 */
+	uint32_t linux_input_type;
+	/* Descriptive name of the key */
+	const char *label;
+	/* Can this key wake-up the system? */
+	bool is_wakeup_source;
+	/* Can this key be disabled? */
+	bool can_be_disabled;
+	/* Debounce interval time in milliseconds */
+	uint32_t debounce_interval;
+};
+
+struct drivers_generic_gpio_keys_config {
+	/* Device name of the parent gpio-keys node */
+	const char *name;
+	/* GPIO line providing the key - Mandatory */
+	struct acpi_gpio gpio;
+	/* Is this a polled GPIO button? - Optional */
+	bool is_polled;
+	/* Poll inverval - Mandatory only if GPIO is polled. */
+	uint32_t poll_interval;
+	/* Details about the key - Mandatory */
+	struct key_info key;
+};
+
+#endif /* __DRIVERS_GENERIC_GPIO_KEYS_H__ */
diff --git a/src/drivers/generic/gpio_keys/gpio_keys.c b/src/drivers/generic/gpio_keys/gpio_keys.c
new file mode 100644
index 0000000000..cbaf8cfe4f
--- /dev/null
+++ b/src/drivers/generic/gpio_keys/gpio_keys.c
@@ -0,0 +1,129 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2018 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 <string.h>
+
+#include "chip.h"
+
+static struct acpi_dp *gpio_keys_add_child_node(
+			struct drivers_generic_gpio_keys_config *config,
+			const char *parent_path)
+{
+	struct key_info *key = &config->key;
+	struct acpi_dp *dsd;
+
+	if (!key->dev_name || !key->linux_code)
+		return NULL;
+
+	dsd = acpi_dp_new_table(config->key.dev_name);
+
+	acpi_dp_add_integer(dsd, "linux,code", key->linux_code);
+	if (key->linux_input_type)
+		acpi_dp_add_integer(dsd, "linux,input-type",
+				    key->linux_input_type);
+	if (key->label)
+		acpi_dp_add_string(dsd, "label", key->label);
+	if (key->is_wakeup_source)
+		acpi_dp_add_integer(dsd, "wakeup-source",
+				    key->is_wakeup_source);
+	if (key->can_be_disabled)
+		acpi_dp_add_integer(dsd, "linux,can-disable",
+				    key->can_be_disabled);
+	if (key->debounce_interval)
+		acpi_dp_add_integer(dsd, "debounce-interval",
+				    key->debounce_interval);
+	acpi_dp_add_gpio(dsd, "gpios", parent_path, 0, 0,
+			 config->gpio.polarity);
+
+	return dsd;
+}
+
+static void gpio_keys_fill_ssdt_generator(struct device *dev)
+{
+	struct drivers_generic_gpio_keys_config *config = dev->chip_info;
+	const char *scope = acpi_device_scope(dev);
+	const char *path = acpi_device_path(dev);
+	struct acpi_dp *dsd, *child;
+	const char *drv_string = config->is_polled ? "gpio-keys-polled"
+				: "gpio-keys";
+
+	if (!dev->enabled || !scope || !path || !config->gpio.pin_count)
+		return;
+
+	/* Device */
+	acpigen_write_scope(scope);
+	acpigen_write_device(acpi_device_name(dev));
+
+	/* _HID is set to PRP0001 */
+	acpigen_write_name_string("_HID", ACPI_DT_NAMESPACE_HID);
+
+	/* Resources - _CRS */
+	acpigen_write_name("_CRS");
+	acpigen_write_resourcetemplate_header();
+	acpi_device_write_gpio(&config->gpio);
+	acpigen_write_resourcetemplate_footer();
+
+	/* DSD */
+	dsd = acpi_dp_new_table("_DSD");
+	acpi_dp_add_string(dsd, "compatible", drv_string);
+	if (config->is_polled)
+		acpi_dp_add_integer(dsd, "poll-interval",
+				 	config->poll_interval);
+	/* Child device defining key */
+	child = gpio_keys_add_child_node(config, path);
+	if (child)
+		acpi_dp_add_child(dsd, "button-0", child);
+	acpi_dp_write(dsd);
+
+	acpigen_pop_len(); /* Device */
+	acpigen_pop_len(); /* Scope */
+}
+
+static const char *gpio_keys_acpi_name(const struct device *dev)
+{
+	struct drivers_generic_gpio_keys_config *config = dev->chip_info;
+	static char name[5];
+
+	if (config->name)
+		return config->name;
+
+	snprintf(name, sizeof(name), "K%03.3X", config->gpio.pins[0]);
+	name[4] = '\0';
+
+	return name;
+}
+
+static struct device_operations gpio_keys_ops = {
+	.read_resources			= DEVICE_NOOP,
+	.set_resources		  	= DEVICE_NOOP,
+	.enable_resources	  	= DEVICE_NOOP,
+	.acpi_name			= &gpio_keys_acpi_name,
+	.acpi_fill_ssdt_generator	= &gpio_keys_fill_ssdt_generator,
+};
+
+static void gpio_keys_enable(struct device *dev)
+{
+	dev->ops = &gpio_keys_ops;
+}
+
+struct chip_operations drivers_generic_gpio_keys_ops = {
+	CHIP_NAME("GPIO Keys")
+	.enable_dev = &gpio_keys_enable
+};