| Mathias Nyman | e29482e | 2012-11-30 12:37:36 +0100 | [diff] [blame] | 1 | /* |
| 2 | * ACPI helpers for GPIO API |
| 3 | * |
| 4 | * Copyright (C) 2012, Intel Corporation |
| 5 | * Authors: Mathias Nyman <mathias.nyman@linux.intel.com> |
| 6 | * Mika Westerberg <mika.westerberg@linux.intel.com> |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU General Public License version 2 as |
| 10 | * published by the Free Software Foundation. |
| 11 | */ |
| 12 | |
| 13 | #include <linux/errno.h> |
| 14 | #include <linux/gpio.h> |
| 15 | #include <linux/export.h> |
| 16 | #include <linux/acpi_gpio.h> |
| 17 | #include <linux/acpi.h> |
| 18 | |
| 19 | static int acpi_gpiochip_find(struct gpio_chip *gc, void *data) |
| 20 | { |
| 21 | if (!gc->dev) |
| 22 | return false; |
| 23 | |
| 24 | return ACPI_HANDLE(gc->dev) == data; |
| 25 | } |
| 26 | |
| 27 | /** |
| 28 | * acpi_get_gpio() - Translate ACPI GPIO pin to GPIO number usable with GPIO API |
| 29 | * @path: ACPI GPIO controller full path name, (e.g. "\\_SB.GPO1") |
| 30 | * @pin: ACPI GPIO pin number (0-based, controller-relative) |
| 31 | * |
| 32 | * Returns GPIO number to use with Linux generic GPIO API, or errno error value |
| 33 | */ |
| 34 | |
| 35 | int acpi_get_gpio(char *path, int pin) |
| 36 | { |
| 37 | struct gpio_chip *chip; |
| 38 | acpi_handle handle; |
| 39 | acpi_status status; |
| 40 | |
| 41 | status = acpi_get_handle(NULL, path, &handle); |
| 42 | if (ACPI_FAILURE(status)) |
| 43 | return -ENODEV; |
| 44 | |
| 45 | chip = gpiochip_find(handle, acpi_gpiochip_find); |
| 46 | if (!chip) |
| 47 | return -ENODEV; |
| 48 | |
| 49 | if (!gpio_is_valid(chip->base + pin)) |
| 50 | return -EINVAL; |
| 51 | |
| 52 | return chip->base + pin; |
| 53 | } |
| 54 | EXPORT_SYMBOL_GPL(acpi_get_gpio); |