- 根目录:
- 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/export.h>
#include <linux/acpi.h>
#include <linux/interrupt.h>
#include <linux/mutex.h>
#include "gpiolib.h"
struct acpi_gpio_event {
struct list_head node;
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 int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
{
if (!gc->dev)
return false;
return ACPI_HANDLE(gc->dev) == 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)
*
* Returns GPIO descriptor to use with Linux generic GPIO API, or ERR_PTR
* error value
*/
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(-ENODEV);
if (pin < 0 || pin > chip->ngpio)
return ERR_PTR(-EINVAL);
return gpiochip_get_desc(chip, pin);
}
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. */
}
static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares,
void *context)
{
struct acpi_gpio_chip *acpi_gpio = context;
struct gpio_chip *chip = acpi_gpio->chip;
struct acpi_resource_gpio *agpio;
acpi_handle handle, evt_handle;
struct acpi_gpio_event *event;
irq_handler_t handler = NULL;
struct gpio_desc *desc;
unsigned long irqflags;
int ret, pin, irq;
if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
return AE_OK;
agpio = &ares->data.gpio;
if (agpio->connection_type != ACPI_RESOURCE_GPIO_TYPE_INT)
return AE_OK;
handle = ACPI_HANDLE(chip->dev);
pin = agpio->pin_table[0];
if (pin <= 255) {
char ev_name[5];
sprintf(ev_name, "_%c%02X",
agpio->triggering == ACPI_EDGE_SENSITIVE ? 'E' : 'L',
pin);
if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, &evt_handle)))
handler = acpi_gpio_irq_handler;
}
if (!handler) {
if (ACPI_SUCCESS(acpi_get_handle(handle, "_EVT", &evt_handle)))
handler = acpi_gpio_irq_handler_evt;
}
if (!handler)
return AE_BAD_PARAMETER;
desc = gpiochip_request_own_desc(chip, pin, "ACPI:Event");
if (IS_ERR(desc)) {
dev_err(chip->dev, "Failed to request GPIO\n");
return AE_ERROR;
}
gpiod_direction_input(desc);
ret = gpio_lock_as_irq(chip, pin);
if (ret) {
dev_err(chip->dev, "Failed to lock GPIO as interrupt\n");
goto fail_free_desc;
}
irq = gpiod_to_irq(desc);
if (irq < 0) {
dev_err(chip->dev, "Failed to translate GPIO to IRQ\n");
goto fail_unlock_irq;
}
irqflags = IRQF_ONESHOT;
if (agpio->triggering == ACPI_LEVEL_SENSITIVE) {
if (agpio->polarity == ACPI_ACTIVE_HIGH)
irqflags |= IRQF_TRIGGER_HIGH;
else
irqflags |= IRQF_TRIGGER_LOW;
} else {
switch (agpio->polarity) {
case ACPI_ACTIVE_HIGH:
irqflags |= IRQF_TRIGGER_RISING;
break;
case ACPI_ACTIVE_LOW:
irqflags |= IRQF_TRIGGER_FALLING;
break;
default:
irqflags |= IRQF_TRIGGER_RISING |
IRQF_TRIGGER_FALLING;
break;
}
}
event = kzalloc(sizeof(*event), GFP_KERNEL);
if (!event)
goto fail_unlock_irq;
event->handle = evt_handle;
event->irq = irq;
event->pin = pin;
event->desc = desc;
ret = request_threaded_irq(event->irq, NULL, handler, irqflags,
"ACPI:Event", event);
if (ret) {
dev_err(chip->dev, "Failed to setup interrupt handler for %d\n",
event->irq);
goto fail_free_event;
}
list_add_tail(&event->node, &acpi_gpio->events);
return AE_OK;
fail_free_event:
kfree(event);
fail_unlock_irq:
gpio_unlock_as_irq(chip, pin);
fail_free_desc:
gpiochip_free_own_desc(desc);
return AE_ERROR;
}
/**
* acpi_gpiochip_request_interrupts() - Register isr for gpio chip ACPI events
* @chip: GPIO chip
*
* ACPI5 platforms can use GPIO signaled ACPI events. These GPIO interrupts are
* handled by ACPI event methods which need to be called from the GPIO
* chip's interrupt handler. acpi_gpiochip_request_interrupts finds out which
* gpio pins have acpi event methods and assigns interrupt handlers that calls
* the acpi event methods for those pins.
*/
void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
{
struct acpi_gpio_chip *acpi_gpio;
acpi_handle handle;
acpi_status status;
if (!chip->dev || !chip->to_irq)
return;
handle = ACPI_HANDLE(chip->dev);
if (!handle)
return;
status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
if (ACPI_FAILURE(status))
return;
INIT_LIST_HEAD(&acpi_gpio->events);
acpi_walk_resources(ACPI_HANDLE(chip->dev), "_AEI",
acpi_gpiochip_request_interrupt, acpi_gpio);
}
/**
* acpi_gpiochip_free_interrupts() - Free GPIO ACPI event interrupts.
* @chip: GPIO chip
*
* Free interrupts associated with GPIO ACPI event method for the given
* GPIO chip.
*/
void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
{
struct acpi_gpio_chip *acpi_gpio;
struct acpi_gpio_event *event, *ep;
acpi_handle handle;
acpi_status status;
if (!chip->dev || !chip->to_irq)
return;
handle = ACPI_HANDLE(chip->dev);
if (!handle)
return;
status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
if (ACPI_FAILURE(status))
return;
list_for_each_entry_safe_reverse(event, ep, &acpi_gpio->events, node) {
struct gpio_desc *desc;
free_irq(event->irq, event);
desc = event->desc;
if (WARN_ON(IS_ERR(desc)))
continue;
gpio_unlock_as_irq(chip, event->pin);
gpiochip_free_own_desc(desc);
list_del(&event->node);
kfree(event);
}
}
struct acpi_gpio_lookup {
struct acpi_gpio_info info;
int index;
struct gpio_desc *desc;
int n;
};
static int acpi_find_gpio(struct acpi_resource *ares, void *data)
{
struct acpi_gpio_lookup *lookup = data;
if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
return 1;
if (lookup->n++ == lookup->index && !lookup->desc) {
const struct acpi_resource_gpio *agpio = &ares->data.gpio;
lookup->desc = acpi_get_gpiod(agpio->resource_source.string_ptr,
agpio->pin_table[0]);
lookup->info.gpioint =
agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;
lookup->info.active_low =
agpio->polarity == ACPI_ACTIVE_LOW;
}
return 1;
}
/**
* acpi_get_gpiod_by_index() - get a GPIO descriptor from device resources
* @dev: pointer to a device to get GPIO from
* @index: index of GpioIo/GpioInt resource (starting from %0)
* @info: info pointer to fill in (optional)
*
* Function goes through ACPI resources for @dev and based on @index looks
* up a GpioIo/GpioInt resource, translates it to the Linux GPIO descriptor,
* and returns it. @index matches GpioIo/GpioInt resources only so if there
* are total %3 GPIO resources, the index goes from %0 to %2.
*
* If the GPIO cannot be translated or there is an error an ERR_PTR is
* returned.
*
* Note: if the GPIO resource has multiple entries in the pin list, this
* function only returns the first.
*/
struct gpio_desc *acpi_get_gpiod_by_index(struct device *dev, int index,
struct acpi_gpio_info *info)
{
struct acpi_gpio_lookup lookup;
struct list_head resource_list;
struct acpi_device *adev;
acpi_handle handle;
int ret;
if (!dev)
return ERR_PTR(-EINVAL);
handle = ACPI_HANDLE(dev);
if (!handle || acpi_bus_get_device(handle, &adev))
return ERR_PTR(-ENODEV);
memset(&lookup, 0, sizeof(lookup));
lookup.index = index;
INIT_LIST_HEAD(&resource_list);
ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio,
&lookup);
if (ret < 0)
return ERR_PTR(ret);
acpi_dev_free_resource_list(&resource_list);
if (lookup.desc && info)
*info = lookup.info;
return lookup.desc ? lookup.desc : ERR_PTR(-ENOENT);
}
static acpi_status
acpi_gpio_adr_space_handler(u32 function, acpi_physical_address address,
u32 bits, u64 *value, void *handler_context,
void *region_context)
{
struct acpi_gpio_chip *achip = region_context;
struct gpio_chip *chip = achip->chip;
struct acpi_resource_gpio *agpio;
struct acpi_resource *ares;
int pin_index = (int)address;
acpi_status status;
bool pull_up;
int length;
int i;
status = acpi_buffer_to_resource(achip->conn_info.connection,
achip->conn_info.length, &ares);
if (ACPI_FAILURE(status))
return status;
if (WARN_ON(ares->type != ACPI_RESOURCE_TYPE_GPIO)) {
ACPI_FREE(ares);
return AE_BAD_PARAMETER;
}
agpio = &ares->data.gpio;
pull_up = agpio->pin_config == ACPI_PIN_CONFIG_PULLUP;
if (WARN_ON(agpio->io_restriction == ACPI_IO_RESTRICT_INPUT &&
function == ACPI_WRITE)) {
ACPI_FREE(ares);
return AE_BAD_PARAMETER;
}
length = min(agpio->pin_table_length, (u16)(pin_index + bits));
for (i = pin_index; i < length; ++i) {
unsigned pin = agpio->pin_table[i];
struct acpi_gpio_connection *conn;
struct gpio_desc *desc;
bool found;
mutex_lock(&achip->conn_lock);
found = false;
list_for_each_entry(conn, &achip->conns, node) {
if (conn->pin == pin) {
found = true;
desc = conn->desc;
break;
}
}
if (!found) {
desc = gpiochip_request_own_desc(chip, pin,
"ACPI:OpRegion");
if (IS_ERR(desc)) {
status = AE_ERROR;
mutex_unlock(&achip->conn_lock);
goto out;
}
switch (agpio->io_restriction) {
case ACPI_IO_RESTRICT_INPUT:
gpiod_direction_input(desc);
break;
case ACPI_IO_RESTRICT_OUTPUT:
/*
* ACPI GPIO resources don't contain an
* initial value for the GPIO. Therefore we
* deduce that value from the pull field
* instead. If the pin is pulled up we
* assume default to be high, otherwise
* low.
*/
gpiod_direction_output(desc, pull_up);
break;
default:
/*
* Assume that the BIOS has configured the
* direction and pull accordingly.
*/
break;
}
conn = kzalloc(sizeof(*conn), GFP_KERNEL);
if (!conn) {
status = AE_NO_MEMORY;
gpiochip_free_own_desc(desc);
mutex_unlock(&achip->conn_lock);
goto out;
}
conn->pin = pin;
conn->desc = desc;
list_add_tail(&conn->node, &achip->conns);
}
mutex_unlock(&achip->conn_lock);
if (function == ACPI_WRITE)
gpiod_set_raw_value_cansleep(desc,
!!((1 << i) & *value));
else
*value |= (u64)gpiod_get_raw_value_cansleep(desc) << i;
}
out:
ACPI_FREE(ares);
return status;
}
static void acpi_gpiochip_request_regions(struct acpi_gpio_chip *achip)
{
struct gpio_chip *chip = achip->chip;
acpi_handle handle = ACPI_HANDLE(chip->dev);
acpi_status status;
INIT_LIST_HEAD(&achip->conns);
mutex_init(&achip->conn_lock);
status = acpi_install_address_space_handler(handle, ACPI_ADR_SPACE_GPIO,
acpi_gpio_adr_space_handler,
NULL, achip);
if (ACPI_FAILURE(status))
dev_err(chip->dev, "Failed to install GPIO OpRegion handler\n");
}
static void acpi_gpiochip_free_regions(struct acpi_gpio_chip *achip)
{
struct gpio_chip *chip = achip->chip;
acpi_handle handle = ACPI_HANDLE(chip->dev);
struct acpi_gpio_connection *conn, *tmp;
acpi_status status;
status = acpi_remove_address_space_handler(handle, ACPI_ADR_SPACE_GPIO,
acpi_gpio_adr_space_handler);
if (ACPI_FAILURE(status)) {
dev_err(chip->dev, "Failed to remove GPIO OpRegion handler\n");
return;
}
list_for_each_entry_safe_reverse(conn, tmp, &achip->conns, node) {
gpiochip_free_own_desc(conn->desc);
list_del(&conn->node);
kfree(conn);
}
}
void acpi_gpiochip_add(struct gpio_chip *chip)
{
struct acpi_gpio_chip *acpi_gpio;
acpi_handle handle;
acpi_status status;
if (!chip || !chip->dev)
return;
handle = ACPI_HANDLE(chip->dev);
if (!handle)
return;
acpi_gpio = kzalloc(sizeof(*acpi_gpio), GFP_KERNEL);
if (!acpi_gpio) {
dev_err(chip->dev,
"Failed to allocate memory for ACPI GPIO chip\n");
return;
}
acpi_gpio->chip = chip;
status = acpi_attach_data(handle, acpi_gpio_chip_dh, acpi_gpio);
if (ACPI_FAILURE(status)) {
dev_err(chip->dev, "Failed to attach ACPI GPIO chip\n");
kfree(acpi_gpio);
return;
}
acpi_gpiochip_request_regions(acpi_gpio);
}
void acpi_gpiochip_remove(struct gpio_chip *chip)
{
struct acpi_gpio_chip *acpi_gpio;
acpi_handle handle;
acpi_status status;
if (!chip || !chip->dev)
return;
handle = ACPI_HANDLE(chip->dev);
if (!handle)
return;
status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
if (ACPI_FAILURE(status)) {
dev_warn(chip->dev, "Failed to retrieve ACPI GPIO chip\n");
return;
}
acpi_gpiochip_free_regions(acpi_gpio);
acpi_detach_data(handle, acpi_gpio_chip_dh);
kfree(acpi_gpio);
}