142 lines
3.5 KiB
C
142 lines
3.5 KiB
C
/*
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* ACPI helpers for GPIO API
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*
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* Copyright (C) 2012, Intel Corporation
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* Authors: Mathias Nyman <mathias.nyman@linux.intel.com>
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* Mika Westerberg <mika.westerberg@linux.intel.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/errno.h>
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#include <linux/gpio.h>
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#include <linux/export.h>
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#include <linux/acpi_gpio.h>
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#include <linux/acpi.h>
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#include <linux/interrupt.h>
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static int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
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{
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if (!gc->dev)
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return false;
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return ACPI_HANDLE(gc->dev) == data;
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}
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/**
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* acpi_get_gpio() - Translate ACPI GPIO pin to GPIO number usable with GPIO API
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* @path: ACPI GPIO controller full path name, (e.g. "\\_SB.GPO1")
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* @pin: ACPI GPIO pin number (0-based, controller-relative)
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*
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* Returns GPIO number to use with Linux generic GPIO API, or errno error value
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*/
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int acpi_get_gpio(char *path, int pin)
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{
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struct gpio_chip *chip;
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acpi_handle handle;
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acpi_status status;
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status = acpi_get_handle(NULL, path, &handle);
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if (ACPI_FAILURE(status))
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return -ENODEV;
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chip = gpiochip_find(handle, acpi_gpiochip_find);
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if (!chip)
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return -ENODEV;
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if (!gpio_is_valid(chip->base + pin))
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return -EINVAL;
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return chip->base + pin;
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}
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EXPORT_SYMBOL_GPL(acpi_get_gpio);
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static irqreturn_t acpi_gpio_irq_handler(int irq, void *data)
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{
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acpi_handle handle = data;
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acpi_evaluate_object(handle, NULL, NULL, NULL);
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return IRQ_HANDLED;
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}
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/**
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* acpi_gpiochip_request_interrupts() - Register isr for gpio chip ACPI events
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* @chip: gpio chip
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*
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* ACPI5 platforms can use GPIO signaled ACPI events. These GPIO interrupts are
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* handled by ACPI event methods which need to be called from the GPIO
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* chip's interrupt handler. acpi_gpiochip_request_interrupts finds out which
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* gpio pins have acpi event methods and assigns interrupt handlers that calls
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* the acpi event methods for those pins.
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*
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* Interrupts are automatically freed on driver detach
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*/
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void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
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{
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struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
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struct acpi_resource *res;
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acpi_handle handle, ev_handle;
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acpi_status status;
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unsigned int pin;
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int irq, ret;
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char ev_name[5];
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if (!chip->dev || !chip->to_irq)
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return;
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handle = ACPI_HANDLE(chip->dev);
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if (!handle)
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return;
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status = acpi_get_event_resources(handle, &buf);
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if (ACPI_FAILURE(status))
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return;
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/* If a gpio interrupt has an acpi event handler method, then
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* set up an interrupt handler that calls the acpi event handler
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*/
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for (res = buf.pointer;
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res && (res->type != ACPI_RESOURCE_TYPE_END_TAG);
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res = ACPI_NEXT_RESOURCE(res)) {
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if (res->type != ACPI_RESOURCE_TYPE_GPIO ||
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res->data.gpio.connection_type !=
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ACPI_RESOURCE_GPIO_TYPE_INT)
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continue;
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pin = res->data.gpio.pin_table[0];
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if (pin > chip->ngpio)
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continue;
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sprintf(ev_name, "_%c%02X",
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res->data.gpio.triggering ? 'E' : 'L', pin);
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status = acpi_get_handle(handle, ev_name, &ev_handle);
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if (ACPI_FAILURE(status))
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continue;
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irq = chip->to_irq(chip, pin);
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if (irq < 0)
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continue;
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/* Assume BIOS sets the triggering, so no flags */
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ret = devm_request_threaded_irq(chip->dev, irq, NULL,
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acpi_gpio_irq_handler,
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0,
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"GPIO-signaled-ACPI-event",
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ev_handle);
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if (ret)
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dev_err(chip->dev,
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"Failed to request IRQ %d ACPI event handler\n",
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irq);
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}
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}
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EXPORT_SYMBOL(acpi_gpiochip_request_interrupts);
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