diff options
Diffstat (limited to 'drivers/gpio/gpiolib-acpi.c')
| -rw-r--r-- | drivers/gpio/gpiolib-acpi.c | 556 |
1 files changed, 556 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c new file mode 100644 index 00000000000..4a987917c18 --- /dev/null +++ b/drivers/gpio/gpiolib-acpi.c @@ -0,0 +1,556 @@ +/* + * 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/consumer.h> +#include <linux/gpio/driver.h> +#include <linux/export.h> +#include <linux/acpi.h> +#include <linux/interrupt.h> +#include <linux/mutex.h> + +#include "gpiolib.h" + +struct acpi_gpio_event { + struct list_head node; + acpi_handle handle; + unsigned int pin; + unsigned int irq; +}; + +struct acpi_gpio_connection { + struct list_head node; + struct gpio_desc *desc; +}; + +struct acpi_gpio_chip { + /* + * ACPICA requires that the first field of the context parameter + * passed to acpi_install_address_space_handler() is large enough + * to hold struct acpi_connection_info. + */ + struct acpi_connection_info conn_info; + struct list_head conns; + struct mutex conn_lock; + struct gpio_chip *chip; + struct list_head events; +}; + +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 gpiochip_get_desc(chip, pin); +} + +static irqreturn_t acpi_gpio_irq_handler(int irq, void *data) +{ + struct acpi_gpio_event *event = data; + + acpi_evaluate_object(event->handle, NULL, NULL, NULL); + + return IRQ_HANDLED; +} + +static irqreturn_t acpi_gpio_irq_handler_evt(int irq, void *data) +{ + struct acpi_gpio_event *event = data; + + acpi_execute_simple_method(event->handle, NULL, event->pin); + + return IRQ_HANDLED; +} + +static void acpi_gpio_chip_dh(acpi_handle handle, void *data) +{ + /* The address of this function is used as a key. */ +} + +static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares, + void *context) +{ + struct acpi_gpio_chip *acpi_gpio = context; + struct gpio_chip *chip = acpi_gpio->chip; + struct acpi_resource_gpio *agpio; + acpi_handle handle, evt_handle; + struct acpi_gpio_event *event; + irq_handler_t handler = NULL; + struct gpio_desc *desc; + unsigned long irqflags; + int ret, pin, irq; + + if (ares->type != ACPI_RESOURCE_TYPE_GPIO) + return AE_OK; + + agpio = &ares->data.gpio; + if (agpio->connection_type != ACPI_RESOURCE_GPIO_TYPE_INT) + return AE_OK; + + handle = ACPI_HANDLE(chip->dev); + pin = agpio->pin_table[0]; + + if (pin <= 255) { + char ev_name[5]; + sprintf(ev_name, "_%c%02X", + agpio->triggering == ACPI_EDGE_SENSITIVE ? 'E' : 'L', + pin); + if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, &evt_handle))) + handler = acpi_gpio_irq_handler; + } + if (!handler) { + if (ACPI_SUCCESS(acpi_get_handle(handle, "_EVT", &evt_handle))) + handler = acpi_gpio_irq_handler_evt; + } + if (!handler) + return AE_BAD_PARAMETER; + + desc = gpiochip_get_desc(chip, pin); + if (IS_ERR(desc)) { + dev_err(chip->dev, "Failed to get GPIO descriptor\n"); + return AE_ERROR; + } + + ret = gpiochip_request_own_desc(desc, "ACPI:Event"); + if (ret) { + dev_err(chip->dev, "Failed to request GPIO\n"); + return AE_ERROR; + } + + gpiod_direction_input(desc); + + ret = gpiod_lock_as_irq(desc); + if (ret) { + dev_err(chip->dev, "Failed to lock GPIO as interrupt\n"); + goto fail_free_desc; + } + + irq = gpiod_to_irq(desc); + if (irq < 0) { + dev_err(chip->dev, "Failed to translate GPIO to IRQ\n"); + goto fail_unlock_irq; + } + + irqflags = IRQF_ONESHOT; + if (agpio->triggering == ACPI_LEVEL_SENSITIVE) { + if (agpio->polarity == ACPI_ACTIVE_HIGH) + irqflags |= IRQF_TRIGGER_HIGH; + else + irqflags |= IRQF_TRIGGER_LOW; + } else { + switch (agpio->polarity) { + case ACPI_ACTIVE_HIGH: + irqflags |= IRQF_TRIGGER_RISING; + break; + case ACPI_ACTIVE_LOW: + irqflags |= IRQF_TRIGGER_FALLING; + break; + default: + irqflags |= IRQF_TRIGGER_RISING | + IRQF_TRIGGER_FALLING; + break; + } + } + + event = kzalloc(sizeof(*event), GFP_KERNEL); + if (!event) + goto fail_unlock_irq; + + event->handle = evt_handle; + event->irq = irq; + event->pin = pin; + + ret = request_threaded_irq(event->irq, NULL, handler, irqflags, + "ACPI:Event", event); + if (ret) { + dev_err(chip->dev, "Failed to setup interrupt handler for %d\n", + event->irq); + goto fail_free_event; + } + + list_add_tail(&event->node, &acpi_gpio->events); + return AE_OK; + +fail_free_event: + kfree(event); +fail_unlock_irq: + gpiod_unlock_as_irq(desc); +fail_free_desc: + gpiochip_free_own_desc(desc); + + return AE_ERROR; +} + +/** + * acpi_gpiochip_request_interrupts() - Register isr for gpio chip ACPI events + * @acpi_gpio: ACPI 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 acpi_gpio_chip *acpi_gpio) +{ + struct gpio_chip *chip = acpi_gpio->chip; + + if (!chip->to_irq) + return; + + INIT_LIST_HEAD(&acpi_gpio->events); + acpi_walk_resources(ACPI_HANDLE(chip->dev), "_AEI", + acpi_gpiochip_request_interrupt, acpi_gpio); +} + +/** + * acpi_gpiochip_free_interrupts() - Free GPIO ACPI event interrupts. + * @acpi_gpio: ACPI GPIO chip + * + * Free interrupts associated with GPIO ACPI event method for the given + * GPIO chip. + */ +static void acpi_gpiochip_free_interrupts(struct acpi_gpio_chip *acpi_gpio) +{ + struct acpi_gpio_event *event, *ep; + struct gpio_chip *chip = acpi_gpio->chip; + + if (!chip->to_irq) + return; + + list_for_each_entry_safe_reverse(event, ep, &acpi_gpio->events, node) { + struct gpio_desc *desc; + + free_irq(event->irq, event); + desc = gpiochip_get_desc(chip, event->pin); + if (WARN_ON(IS_ERR(desc))) + continue; + gpiod_unlock_as_irq(desc); + gpiochip_free_own_desc(desc); + list_del(&event->node); + kfree(event); + } +} + +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); +} + +static acpi_status +acpi_gpio_adr_space_handler(u32 function, acpi_physical_address address, + u32 bits, u64 *value, void *handler_context, + void *region_context) +{ + struct acpi_gpio_chip *achip = region_context; + struct gpio_chip *chip = achip->chip; + struct acpi_resource_gpio *agpio; + struct acpi_resource *ares; + acpi_status status; + bool pull_up; + int i; + + status = acpi_buffer_to_resource(achip->conn_info.connection, + achip->conn_info.length, &ares); + if (ACPI_FAILURE(status)) + return status; + + if (WARN_ON(ares->type != ACPI_RESOURCE_TYPE_GPIO)) { + ACPI_FREE(ares); + return AE_BAD_PARAMETER; + } + + agpio = &ares->data.gpio; + pull_up = agpio->pin_config == ACPI_PIN_CONFIG_PULLUP; + + if (WARN_ON(agpio->io_restriction == ACPI_IO_RESTRICT_INPUT && + function == ACPI_WRITE)) { + ACPI_FREE(ares); + return AE_BAD_PARAMETER; + } + + for (i = 0; i < agpio->pin_table_length; i++) { + unsigned pin = agpio->pin_table[i]; + struct acpi_gpio_connection *conn; + struct gpio_desc *desc; + bool found; + + desc = gpiochip_get_desc(chip, pin); + if (IS_ERR(desc)) { + status = AE_ERROR; + goto out; + } + + mutex_lock(&achip->conn_lock); + + found = false; + list_for_each_entry(conn, &achip->conns, node) { + if (conn->desc == desc) { + found = true; + break; + } + } + if (!found) { + int ret; + + ret = gpiochip_request_own_desc(desc, "ACPI:OpRegion"); + if (ret) { + status = AE_ERROR; + mutex_unlock(&achip->conn_lock); + goto out; + } + + switch (agpio->io_restriction) { + case ACPI_IO_RESTRICT_INPUT: + gpiod_direction_input(desc); + break; + case ACPI_IO_RESTRICT_OUTPUT: + /* + * ACPI GPIO resources don't contain an + * initial value for the GPIO. Therefore we + * deduce that value from the pull field + * instead. If the pin is pulled up we + * assume default to be high, otherwise + * low. + */ + gpiod_direction_output(desc, pull_up); + break; + default: + /* + * Assume that the BIOS has configured the + * direction and pull accordingly. + */ + break; + } + + conn = kzalloc(sizeof(*conn), GFP_KERNEL); + if (!conn) { + status = AE_NO_MEMORY; + gpiochip_free_own_desc(desc); + mutex_unlock(&achip->conn_lock); + goto out; + } + + conn->desc = desc; + list_add_tail(&conn->node, &achip->conns); + } + + mutex_unlock(&achip->conn_lock); + + if (function == ACPI_WRITE) + gpiod_set_raw_value_cansleep(desc, + !!((1 << i) & *value)); + else + *value |= (u64)gpiod_get_raw_value_cansleep(desc) << i; + } + +out: + ACPI_FREE(ares); + return status; +} + +static void acpi_gpiochip_request_regions(struct acpi_gpio_chip *achip) +{ + struct gpio_chip *chip = achip->chip; + acpi_handle handle = ACPI_HANDLE(chip->dev); + acpi_status status; + + INIT_LIST_HEAD(&achip->conns); + mutex_init(&achip->conn_lock); + status = acpi_install_address_space_handler(handle, ACPI_ADR_SPACE_GPIO, + acpi_gpio_adr_space_handler, + NULL, achip); + if (ACPI_FAILURE(status)) + dev_err(chip->dev, "Failed to install GPIO OpRegion handler\n"); +} + +static void acpi_gpiochip_free_regions(struct acpi_gpio_chip *achip) +{ + struct gpio_chip *chip = achip->chip; + acpi_handle handle = ACPI_HANDLE(chip->dev); + struct acpi_gpio_connection *conn, *tmp; + acpi_status status; + + status = acpi_remove_address_space_handler(handle, ACPI_ADR_SPACE_GPIO, + acpi_gpio_adr_space_handler); + if (ACPI_FAILURE(status)) { + dev_err(chip->dev, "Failed to remove GPIO OpRegion handler\n"); + return; + } + + list_for_each_entry_safe_reverse(conn, tmp, &achip->conns, node) { + gpiochip_free_own_desc(conn->desc); + list_del(&conn->node); + kfree(conn); + } +} + +void acpi_gpiochip_add(struct gpio_chip *chip) +{ + struct acpi_gpio_chip *acpi_gpio; + acpi_handle handle; + acpi_status status; + + if (!chip || !chip->dev) + return; + + handle = ACPI_HANDLE(chip->dev); + if (!handle) + return; + + acpi_gpio = kzalloc(sizeof(*acpi_gpio), GFP_KERNEL); + if (!acpi_gpio) { + dev_err(chip->dev, + "Failed to allocate memory for ACPI GPIO chip\n"); + return; + } + + acpi_gpio->chip = chip; + + status = acpi_attach_data(handle, acpi_gpio_chip_dh, acpi_gpio); + if (ACPI_FAILURE(status)) { + dev_err(chip->dev, "Failed to attach ACPI GPIO chip\n"); + kfree(acpi_gpio); + return; + } + + acpi_gpiochip_request_interrupts(acpi_gpio); + acpi_gpiochip_request_regions(acpi_gpio); +} + +void acpi_gpiochip_remove(struct gpio_chip *chip) +{ + struct acpi_gpio_chip *acpi_gpio; + acpi_handle handle; + acpi_status status; + + if (!chip || !chip->dev) + return; + + handle = ACPI_HANDLE(chip->dev); + if (!handle) + return; + + status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio); + if (ACPI_FAILURE(status)) { + dev_warn(chip->dev, "Failed to retrieve ACPI GPIO chip\n"); + return; + } + + acpi_gpiochip_free_regions(acpi_gpio); + acpi_gpiochip_free_interrupts(acpi_gpio); + + acpi_detach_data(handle, acpi_gpio_chip_dh); + kfree(acpi_gpio); +} |