diff options
Diffstat (limited to 'drivers/gpio')
| -rw-r--r-- | drivers/gpio/gpiolib-acpi.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c index 89336c4f82cd..5c1ef2b3ef18 100644 --- a/drivers/gpio/gpiolib-acpi.c +++ b/drivers/gpio/gpiolib-acpi.c @@ -201,6 +201,83 @@ void acpi_gpiochip_request_interrupts(struct gpio_chip *chip) } EXPORT_SYMBOL(acpi_gpiochip_request_interrupts); +struct acpi_gpio_lookup { + struct acpi_gpio_info info; + int index; + int gpio; + 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->gpio < 0) { + const struct acpi_resource_gpio *agpio = &ares->data.gpio; + + lookup->gpio = acpi_get_gpio(agpio->resource_source.string_ptr, + agpio->pin_table[0]); + lookup->info.gpioint = + agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT; + } + + return 1; +} + +/** + * acpi_get_gpio_by_index() - get a GPIO number 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 number, + * 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, negative errno is + * returned. + * + * Note: if the GPIO resource has multiple entries in the pin list, this + * function only returns the first. + */ +int acpi_get_gpio_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 -EINVAL; + + handle = ACPI_HANDLE(dev); + if (!handle || acpi_bus_get_device(handle, &adev)) + return -ENODEV; + + memset(&lookup, 0, sizeof(lookup)); + lookup.index = index; + lookup.gpio = -ENODEV; + + INIT_LIST_HEAD(&resource_list); + ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio, + &lookup); + if (ret < 0) + return ret; + + acpi_dev_free_resource_list(&resource_list); + + if (lookup.gpio >= 0 && info) + *info = lookup.info; + + return lookup.gpio; +} +EXPORT_SYMBOL_GPL(acpi_get_gpio_by_index); /** * acpi_gpiochip_free_interrupts() - Free GPIO _EVT ACPI event interrupts. |