![Mika Westerberg](/assets/img/avatar_default.png)
The ACPI GpioInt resources contain polarity field that is used to specify whether the interrupt is active high or low. Since gpiolib supports GPIOF_ACTIVE_LOW we can pass this information in the flags field in acpi_find_gpio(), analogous to the DeviceTree version. Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
313 lines
7.9 KiB
C
313 lines
7.9 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/consumer.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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struct acpi_gpio_evt_pin {
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struct list_head node;
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acpi_handle *evt_handle;
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unsigned int pin;
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unsigned int irq;
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};
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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_gpiod() - Translate ACPI GPIO pin to GPIO descriptor 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 descriptor to use with Linux generic GPIO API, or ERR_PTR
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* error value
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*/
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static struct gpio_desc *acpi_get_gpiod(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 ERR_PTR(-ENODEV);
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chip = gpiochip_find(handle, acpi_gpiochip_find);
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if (!chip)
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return ERR_PTR(-ENODEV);
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if (pin < 0 || pin > chip->ngpio)
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return ERR_PTR(-EINVAL);
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return gpio_to_desc(chip->base + pin);
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}
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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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static irqreturn_t acpi_gpio_irq_handler_evt(int irq, void *data)
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{
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struct acpi_gpio_evt_pin *evt_pin = data;
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acpi_execute_simple_method(evt_pin->evt_handle, NULL, evt_pin->pin);
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return IRQ_HANDLED;
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}
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static void acpi_gpio_evt_dh(acpi_handle handle, void *data)
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{
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/* The address of this function is used as a key. */
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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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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, evt_handle;
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struct list_head *evt_pins = NULL;
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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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status = acpi_get_handle(handle, "_EVT", &evt_handle);
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if (ACPI_SUCCESS(status)) {
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evt_pins = kzalloc(sizeof(*evt_pins), GFP_KERNEL);
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if (evt_pins) {
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INIT_LIST_HEAD(evt_pins);
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status = acpi_attach_data(handle, acpi_gpio_evt_dh,
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evt_pins);
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if (ACPI_FAILURE(status)) {
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kfree(evt_pins);
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evt_pins = NULL;
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}
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}
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}
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/*
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* If a GPIO interrupt has an ACPI event handler method, or _EVT is
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* present, set up an interrupt handler that calls the ACPI event
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* 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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irq_handler_t handler = NULL;
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void *data;
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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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irq = chip->to_irq(chip, pin);
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if (irq < 0)
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continue;
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if (pin <= 255) {
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acpi_handle ev_handle;
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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_SUCCESS(status)) {
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handler = acpi_gpio_irq_handler;
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data = ev_handle;
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}
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}
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if (!handler && evt_pins) {
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struct acpi_gpio_evt_pin *evt_pin;
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evt_pin = kzalloc(sizeof(*evt_pin), GFP_KERNEL);
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if (!evt_pin)
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continue;
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list_add_tail(&evt_pin->node, evt_pins);
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evt_pin->evt_handle = evt_handle;
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evt_pin->pin = pin;
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evt_pin->irq = irq;
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handler = acpi_gpio_irq_handler_evt;
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data = evt_pin;
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}
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if (!handler)
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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, handler,
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0, "GPIO-signaled-ACPI-event",
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data);
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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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/**
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* acpi_gpiochip_free_interrupts() - Free GPIO _EVT ACPI event interrupts.
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* @chip: gpio chip
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*
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* Free interrupts associated with the _EVT method for the given GPIO chip.
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*
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* The remaining ACPI event interrupts associated with the chip are freed
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* automatically.
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*/
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void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
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{
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acpi_handle handle;
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acpi_status status;
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struct list_head *evt_pins;
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struct acpi_gpio_evt_pin *evt_pin, *ep;
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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_data(handle, acpi_gpio_evt_dh, (void **)&evt_pins);
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if (ACPI_FAILURE(status))
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return;
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list_for_each_entry_safe_reverse(evt_pin, ep, evt_pins, node) {
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devm_free_irq(chip->dev, evt_pin->irq, evt_pin);
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list_del(&evt_pin->node);
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kfree(evt_pin);
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}
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acpi_detach_data(handle, acpi_gpio_evt_dh);
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kfree(evt_pins);
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}
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EXPORT_SYMBOL(acpi_gpiochip_free_interrupts);
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struct acpi_gpio_lookup {
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struct acpi_gpio_info info;
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int index;
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struct gpio_desc *desc;
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int n;
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};
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static int acpi_find_gpio(struct acpi_resource *ares, void *data)
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{
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struct acpi_gpio_lookup *lookup = data;
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if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
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return 1;
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if (lookup->n++ == lookup->index && !lookup->desc) {
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const struct acpi_resource_gpio *agpio = &ares->data.gpio;
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lookup->desc = acpi_get_gpiod(agpio->resource_source.string_ptr,
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agpio->pin_table[0]);
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lookup->info.gpioint =
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agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;
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lookup->info.active_low =
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agpio->polarity == ACPI_ACTIVE_LOW;
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}
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return 1;
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}
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/**
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* acpi_get_gpiod_by_index() - get a GPIO descriptor from device resources
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* @dev: pointer to a device to get GPIO from
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* @index: index of GpioIo/GpioInt resource (starting from %0)
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* @info: info pointer to fill in (optional)
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*
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* Function goes through ACPI resources for @dev and based on @index looks
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* up a GpioIo/GpioInt resource, translates it to the Linux GPIO descriptor,
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* and returns it. @index matches GpioIo/GpioInt resources only so if there
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* are total %3 GPIO resources, the index goes from %0 to %2.
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*
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* If the GPIO cannot be translated or there is an error an ERR_PTR is
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* returned.
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*
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* Note: if the GPIO resource has multiple entries in the pin list, this
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* function only returns the first.
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*/
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struct gpio_desc *acpi_get_gpiod_by_index(struct device *dev, int index,
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struct acpi_gpio_info *info)
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{
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struct acpi_gpio_lookup lookup;
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struct list_head resource_list;
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struct acpi_device *adev;
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acpi_handle handle;
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int ret;
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if (!dev)
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return ERR_PTR(-EINVAL);
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handle = ACPI_HANDLE(dev);
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if (!handle || acpi_bus_get_device(handle, &adev))
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return ERR_PTR(-ENODEV);
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memset(&lookup, 0, sizeof(lookup));
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lookup.index = index;
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INIT_LIST_HEAD(&resource_list);
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ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio,
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&lookup);
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if (ret < 0)
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return ERR_PTR(ret);
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acpi_dev_free_resource_list(&resource_list);
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if (lookup.desc && info)
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*info = lookup.info;
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return lookup.desc ? lookup.desc : ERR_PTR(-ENODEV);
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}
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EXPORT_SYMBOL_GPL(acpi_get_gpiod_by_index);
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