/* * ACPI helpers for GPIO API * * Copyright (C) 2012, Intel Corporation * Authors: Mathias Nyman * Mika Westerberg * * 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 #include #include #include #include #include #include "gpiolib.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_gpiod() - Translate ACPI GPIO pin to GPIO descriptor 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 descriptor to use with Linux generic GPIO API, or ERR_PTR * error value */ static struct gpio_desc *acpi_get_gpiod(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 ERR_PTR(-ENODEV); chip = gpiochip_find(handle, acpi_gpiochip_find); if (!chip) return ERR_PTR(-ENODEV); if (pin < 0 || pin > chip->ngpio) return ERR_PTR(-EINVAL); return gpio_to_desc(chip->base + pin); } 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; acpi_execute_simple_method(evt_pin->evt_handle, NULL, evt_pin->pin); 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. */ static 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); } } /** * 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. */ static 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); } struct acpi_gpio_lookup { struct acpi_gpio_info info; int index; struct gpio_desc *desc; 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->desc) { const struct acpi_resource_gpio *agpio = &ares->data.gpio; lookup->desc = acpi_get_gpiod(agpio->resource_source.string_ptr, agpio->pin_table[0]); lookup->info.gpioint = agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT; lookup->info.active_low = agpio->polarity == ACPI_ACTIVE_LOW; } return 1; } /** * acpi_get_gpiod_by_index() - get a GPIO descriptor 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 descriptor, * 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 an ERR_PTR is * returned. * * Note: if the GPIO resource has multiple entries in the pin list, this * function only returns the first. */ struct gpio_desc *acpi_get_gpiod_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 ERR_PTR(-EINVAL); handle = ACPI_HANDLE(dev); if (!handle || acpi_bus_get_device(handle, &adev)) return ERR_PTR(-ENODEV); memset(&lookup, 0, sizeof(lookup)); lookup.index = index; INIT_LIST_HEAD(&resource_list); ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio, &lookup); if (ret < 0) return ERR_PTR(ret); acpi_dev_free_resource_list(&resource_list); if (lookup.desc && info) *info = lookup.info; return lookup.desc ? lookup.desc : ERR_PTR(-ENOENT); } void acpi_gpiochip_add(struct gpio_chip *chip) { acpi_gpiochip_request_interrupts(chip); } void acpi_gpiochip_remove(struct gpio_chip *chip) { acpi_gpiochip_free_interrupts(chip); }