path: root/drivers/gpio/gpiolib-acpi.c

/*
 * ACPI helpers for GPIO API
 *
 * Copyright (C) 2012, Intel Corporation
 * Authors: Mathias Nyman <mathias.nyman@linux.intel.com>
 *          Mika Westerberg <mika.westerberg@linux.intel.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/errno.h>
#include <linux/gpio/consumer.h>
#include <linux/gpio/driver.h>
#include <linux/gpio/machine.h>
#include <linux/export.h>
#include <linux/acpi.h>
#include <linux/interrupt.h>
#include <linux/mutex.h>
#include <linux/pinctrl/pinctrl.h>

#include "gpiolib.h"

struct acpi_gpio_event {
	struct list_head node;
	struct list_head initial_sync_list;
	acpi_handle handle;
	unsigned int pin;
	unsigned int irq;
	struct gpio_desc *desc;
};

struct acpi_gpio_connection {
	struct list_head node;
	unsigned int pin;
	struct gpio_desc *desc;
};

struct acpi_gpio_chip {
	/*
	 * ACPICA requires that the first field of the context parameter
	 * passed to acpi_install_address_space_handler() is large enough
	 * to hold struct acpi_connection_info.
	 */
	struct acpi_connection_info conn_info;
	struct list_head conns;
	struct mutex conn_lock;
	struct gpio_chip *chip;
	struct list_head events;
};

static LIST_HEAD(acpi_gpio_initial_sync_list);
static DEFINE_MUTEX(acpi_gpio_initial_sync_list_lock);

static int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
{
	if (!gc->parent)
		return false;

	return ACPI_HANDLE(gc->parent) == data;
}

/**
 * acpi_get_gpiod() - Translate ACPI GPIO pin to GPIO descriptor usable with GPIO API
 * @path:	ACPI GPIO controller full path name, (e.g. "\\_SB.GPO1")
 * @pin:	ACPI GPIO pin number (0-based, controller-relative)
 *
 * Return: GPIO descriptor to use with Linux generic GPIO API, or ERR_PTR
 * error value. Specifically returns %-EPROBE_DEFER if the referenced GPIO
 * controller does not have gpiochip registered at the moment. This is to
 * support probe deferral.
 */
static struct gpio_desc *acpi_get_gpiod(char *path, int pin)
{
	struct gpio_chip *chip;
	acpi_handle handle;
	acpi_status status;

	status = acpi_get_handle(NULL, path, &handle);
	if (ACPI_FAILURE(status))
		return ERR_PTR(-ENODEV);

	chip = gpiochip_find(handle, acpi_gpiochip_find);
	if (!chip)
		return ERR_PTR(-EPROBE_DEFER);

	return gpiochip_get_desc(chip, pin);
}

static void acpi_gpio_add_to_initial_sync_list(struct acpi_gpio_event *event)
{
	mutex_lock(&acpi_gpio_initial_sync_list_lock);
	list_add(&event->initial_sync_list, &acpi_gpio_initial_sync_list);
	mutex_unlock(&acpi_gpio_initial_sync_list_lock);
}

static void acpi_gpio_del_from_initial_sync_list(struct acpi_gpio_event *event)
{
	mutex_lock(&acpi_gpio_initial_sync_list_lock);
	if (!list_empty(&event->initial_sync_list))
		list_del_init(&event->initial_sync_list);
	mutex_unlock(&acpi_gpio_initial_sync_list_lock);
}

static irqreturn_t acpi_gpio_irq_handler(int irq, void *data)
{
	struct acpi_gpio_event *event = data;

	acpi_evaluate_object(event->handle, NULL, NULL, NULL);

	return IRQ_HANDLED;
}

static irqreturn_t acpi_gpio_irq_handler_evt(int irq, void *data)
{
	struct acpi_gpio_event *event = data;

	acpi_execute_simple_method(event->handle, NULL, event->pin);

	return IRQ_HANDLED;
}

static void acpi_gpio_chip_dh(acpi_handle handle, void *data)
{
	/* The address of this function is used as a key. */
}

bool acpi_gpio_get_irq_resource(struct acpi_resource *ares,
				struct acpi_resource_gpio **agpio)
{
	struct acpi_resource_gpio *gpio;

	if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
		return false;

	gpio = &ares->data.gpio;
	if (gpio->connection_type != ACPI_RESOURCE_GPIO_TYPE_INT)
		return false;

	*agpio = gpio;
	return true;
}
EXPORT_SYMBOL_GPL(acpi_gpio_get_irq_resource);

static acpi_status acpi_gpiochip_request_interru