linux/drivers/gpio/gpiolib-acpi.c
Mika Westerberg 12028d2d21 gpiolib-acpi: introduce acpi_get_gpio_by_index() helper
Instead of open-coding ACPI GPIO resource lookup in each driver, we provide
a helper function analogous to Device Tree version that allows drivers to
specify which GPIO resource they are interested (using an index to the GPIO
resources). The function then finds out the correct resource, translates
the ACPI GPIO number to the corresponding Linux GPIO number and returns
that.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2013-04-12 00:31:18 +02:00

319 lines
7.8 KiB
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.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);
struct acpi_gpio_lookup {
struct acpi_gpio_info info;
int index;
int gpio;
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->gpio < 0) {
const struct acpi_resource_gpio *agpio = &ares->data.gpio;
lookup->gpio = acpi_get_gpio(agpio->resource_source.string_ptr,
agpio->pin_table[0]);
lookup->info.gpioint =
agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;
}
return 1;
}
/**
* acpi_get_gpio_by_index() - get a GPIO number 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 number,
* 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, negative errno is
* returned.
*
* Note: if the GPIO resource has multiple entries in the pin list, this
* function only returns the first.
*/
int acpi_get_gpio_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 -EINVAL;
handle = ACPI_HANDLE(dev);
if (!handle || acpi_bus_get_device(handle, &adev))
return -ENODEV;
memset(&lookup, 0, sizeof(lookup));
lookup.index = index;
lookup.gpio = -ENODEV;
INIT_LIST_HEAD(&resource_list);
ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio,
&lookup);
if (ret < 0)
return ret;
acpi_dev_free_resource_list(&resource_list);
if (lookup.gpio >= 0 && info)
*info = lookup.info;
return lookup.gpio;
}
EXPORT_SYMBOL_GPL(acpi_get_gpio_by_index);
/**
* 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);