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https://github.com/edk2-porting/linux-next.git
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0d1c28a449
Add ability to handle ACPI events signalled by GPIO interrupts. 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 controller's interrupt handler. acpi_gpio_request_interrupt() finds out which gpio pins have acpi event methods and assigns interrupt handlers that calls the acpi event methods for those pins. Partially based on work by Rui Zhang <rui.zhang@intel.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
137 lines
3.4 KiB
C
137 lines
3.4 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, irq;
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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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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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}
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}
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EXPORT_SYMBOL(acpi_gpiochip_request_interrupts);
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