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/*
* 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.h>
#include <linux/export.h>
#include <linux/acpi_gpio.h>
#include <linux/acpi.h>
#include <linux/interrupt.h>
struct acpi_gpio_evt_pin {
struct list_head node;
acpi_handle *evt_handle;
unsigned int pin;
unsigned int irq;
};
static int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
{
if (!gc->dev)
return false;
return ACPI_HANDLE(gc->dev) == data;
}
/**
* acpi_get_gpio() - Translate ACPI GPIO pin to GPIO number 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 number to use with Linux generic GPIO API, or errno error value
*/
int acpi_get_gpio(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 -ENODEV;
chip = gpiochip_find(handle, acpi_gpiochip_find);
if (!chip)
return -ENODEV;
if (!gpio_is_valid(chip->base + pin))
return -EINVAL;
return chip->base + pin;
}
EXPORT_SYMBOL_GPL(acpi_get_gpio);
static irqreturn_t acpi_gpio_irq_handler(int irq, void *data)
{
acpi_handle handle = data;
acpi_evaluate_object(handle, NULL, NULL, NULL);
return IRQ_HANDLED;
}
static irqreturn_t acpi_gpio_irq_handler_evt(int irq, void *data)
{
struct acpi_gpio_evt_pin *evt_pin = data;
struct acpi_object_list args;
union acpi_object arg;
arg.type = ACPI_TYPE_INTEGER;
arg.integer.value = evt_pin->pin;
args.count = 1;
args.pointer = &arg;
acpi_evaluate_object(evt_pin->evt_handle, NULL, &args, NULL);
return IRQ_HANDLED;
}
static void acpi_gpio_evt_dh(acpi_handle handle, void *data)
{
/* The address of this function is used as a key. */
}
/**
* 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_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
struct acpi_resource *res;
acpi_handle handle, evt_handle;
struct list_head *evt_pins = NULL;
acpi_status status;
unsigned int pin;
int irq, ret;
char ev_name[5];
if (!chip->dev || !chip->to_irq)
return;
handle = ACPI_HANDLE(chip->dev);
if (!handle)
return;
status = acpi_get_event_resources(handle, &buf);
if (ACPI_FAILURE(status))
return;
status = acpi_get_handle(handle, "_EVT", &evt_handle);
if (ACPI_SUCCESS(status)) {
evt_pins = kzalloc(sizeof(*evt_pins), GFP_KERNEL);
if (evt_pins) {
INIT_LIST_HEAD(evt_pins);
status = acpi_attach_data(handle, acpi_gpio_evt_dh,
evt_pins);
if (ACPI_FAILURE(status)) {
kfree(evt_pins);
evt_pins = NULL;
}
}
}
/*
* If a GPIO interrupt has an ACPI event handler method, or _EVT is
* present, set up an interrupt handler that calls the ACPI event
* handler.
*/
for (res = buf.pointer;
res && (res->type != ACPI_RESOURCE_TYPE_END_TAG);
res = ACPI_NEXT_RESOURCE(res)) {
irq_handler_t handler = NULL;
void *data;
if (res->type != ACPI_RESOURCE_TYPE_GPIO ||
res->data.gpio.connection_type !=
ACPI_RESOURCE_GPIO_TYPE_INT)
continue;
pin = res->data.gpio.pin_table[0];
if (pin > chip->ngpio)
continue;
irq = chip->to_irq(chip, pin);
if (irq < 0)
continue;
if (pin <= 255) {
acpi_handle ev_handle;
sprintf(ev_name, "_%c%02X",
res->data.gpio.triggering ? 'E' : 'L', pin);
status = acpi_get_handle(handle, ev_name, &ev_handle);
if (ACPI_SUCCESS(status)) {
handler = acpi_gpio_irq_handler;
data = ev_handle;
}
}
if (!handler && evt_pins) {
struct acpi_gpio_evt_pin *evt_pin;
evt_pin = kzalloc(sizeof(*evt_pin), GFP_KERNEL);
if (!evt_pin)
continue;
list_add_tail(&evt_pin->node, evt_pins);
evt_pin->evt_handle = evt_handle;
evt_pin->pin = pin;
evt_pin->irq = irq;
handler = acpi_gpio_irq_handler_evt;
data = evt_pin;
}
if (!handler)
continue;
/* Assume BIOS sets the triggering, so no flags */
ret = devm_request_threaded_irq(chip->dev, irq, NULL, handler,
0, "GPIO-signaled-ACPI-event",
data);
if (ret)
dev_err(chip->dev,
"Failed to request IRQ %d ACPI event handler\n",
irq);
}
}
EXPORT_SYMBOL(acpi_gpiochip_request_interrupts);
/**
* acpi_gpiochip_free_interrupts() - Free GPIO _EVT ACPI event interrupts.
* @chip: gpio chip
*
* Free interrupts associated with the _EVT method for the given GPIO chip.
*
* The remaining ACPI event interrupts associated with the chip are freed
* automatically.
*/
void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
{
acpi_handle handle;
acpi_status status;
struct list_head *evt_pins;
struct acpi_gpio_evt_pin *evt_pin, *ep;
if (!chip->dev || !chip->to_irq)
return;
handle = ACPI_HANDLE(chip->dev);
if (!handle)
return;
status = acpi_get_data(handle, acpi_gpio_evt_dh, (void **)&evt_pins);
if (ACPI_FAILURE(status))
return;
list_for_each_entry_safe_reverse(evt_pin, ep, evt_pins, node) {
devm_free_irq(chip->dev, evt_pin->irq, evt_pin);
list_del(&evt_pin->node);
kfree(evt_pin);
}
acpi_detach_data(handle, acpi_gpio_evt_dh);
kfree(evt_pins);
}
EXPORT_SYMBOL(acpi_gpiochip_free_interrupts);
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