projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 3d64de9c AV |
1 | /* |
| 2 | * Simple Memory-Mapped GPIOs | |
| 3 | * | |
| 4 | * Copyright (c) MontaVista Software, Inc. 2008. | |
| 5 | * | |
| 6 | * Author: Anton Vorontsov <avorontsov@ru.mvista.com> | |
| 7 | * | |
| 8 | * This program is free software; you can redistribute it and/or modify it | |
| 9 | * under the terms of the GNU General Public License as published by the | |
| 10 | * Free Software Foundation; either version 2 of the License, or (at your | |
| 11 | * option) any later version. | |
| 12 | */ | |
| 13 | ||
| 14 | #include <linux/init.h> | |
| 15 | #include <linux/kernel.h> | |
| 16 | #include <linux/module.h> | |
| 17 | #include <linux/spinlock.h> | |
| 18 | #include <linux/types.h> | |
| 19 | #include <linux/ioport.h> | |
| 20 | #include <linux/io.h> | |
| 21 | #include <linux/of.h> | |
| 22 | #include <linux/of_gpio.h> | |
| 23 | #include <linux/gpio.h> | |
| 5a0e3ad6 | 24 | #include <linux/slab.h> |
| 3d64de9c AV |
25 | #include <asm/prom.h> |
| 26 | #include "simple_gpio.h" | |
| 27 | ||
| 28 | struct u8_gpio_chip { | |
| 29 | struct of_mm_gpio_chip mm_gc; | |
| 30 | spinlock_t lock; | |
| 31 | ||
| 32 | /* shadowed data register to clear/set bits safely */ | |
| 33 | u8 data; | |
| 34 | }; | |
| 35 | ||
| 36 | static struct u8_gpio_chip *to_u8_gpio_chip(struct of_mm_gpio_chip *mm_gc) | |
| 37 | { | |
| 38 | return container_of(mm_gc, struct u8_gpio_chip, mm_gc); | |
| 39 | } | |
| 40 | ||
| 41 | static u8 u8_pin2mask(unsigned int pin) | |
| 42 | { | |
| 43 | return 1 << (8 - 1 - pin); | |
| 44 | } | |
| 45 | ||
| 46 | static int u8_gpio_get(struct gpio_chip *gc, unsigned int gpio) | |
| 47 | { | |
| 48 | struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc); | |
| 49 | ||
| 50 | return in_8(mm_gc->regs) & u8_pin2mask(gpio); | |
| 51 | } | |
| 52 | ||
| 53 | static void u8_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val) | |
| 54 | { | |
| 55 | struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc); | |
| 56 | struct u8_gpio_chip *u8_gc = to_u8_gpio_chip(mm_gc); | |
| 57 | unsigned long flags; | |
| 58 | ||
| 59 | spin_lock_irqsave(&u8_gc->lock, flags); | |
| 60 | ||
| 61 | if (val) | |
| 62 | u8_gc->data |= u8_pin2mask(gpio); | |
| 63 | else | |
| 64 | u8_gc->data &= ~u8_pin2mask(gpio); | |
| 65 | ||
| 66 | out_8(mm_gc->regs, u8_gc->data); | |
| 67 | ||
| 68 | spin_unlock_irqrestore(&u8_gc->lock, flags); | |
| 69 | } | |
| 70 | ||
| 71 | static int u8_gpio_dir_in(struct gpio_chip *gc, unsigned int gpio) | |
| 72 | { | |
| 73 | return 0; | |
| 74 | } | |
| 75 | ||
| 76 | static int u8_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val) | |
| 77 | { | |
| 78 | u8_gpio_set(gc, gpio, val); | |
| 79 | return 0; | |
| 80 | } | |
| 81 | ||
| 82 | static void u8_gpio_save_regs(struct of_mm_gpio_chip *mm_gc) | |
| 83 | { | |
| 84 | struct u8_gpio_chip *u8_gc = to_u8_gpio_chip(mm_gc); | |
| 85 | ||
| 86 | u8_gc->data = in_8(mm_gc->regs); | |
| 87 | } | |
| 88 | ||
| 89 | static int __init u8_simple_gpiochip_add(struct device_node *np) | |
| 90 | { | |
| 91 | int ret; | |
| 92 | struct u8_gpio_chip *u8_gc; | |
| 93 | struct of_mm_gpio_chip *mm_gc; | |
| 94 | struct of_gpio_chip *of_gc; | |
| 95 | struct gpio_chip *gc; | |
| 96 | ||
| 97 | u8_gc = kzalloc(sizeof(*u8_gc), GFP_KERNEL); | |
| 98 | if (!u8_gc) | |
| 99 | return -ENOMEM; | |
| 100 | ||
| 101 | spin_lock_init(&u8_gc->lock); | |
| 102 | ||
| 103 | mm_gc = &u8_gc->mm_gc; | |
| 104 | of_gc = &mm_gc->of_gc; | |
| 105 | gc = &of_gc->gc; | |
| 106 | ||
| 107 | mm_gc->save_regs = u8_gpio_save_regs; | |
| 108 | of_gc->gpio_cells = 2; | |
| 109 | gc->ngpio = 8; | |
| 110 | gc->direction_input = u8_gpio_dir_in; | |
| 111 | gc->direction_output = u8_gpio_dir_out; | |
| 112 | gc->get = u8_gpio_get; | |
| 113 | gc->set = u8_gpio_set; | |
| 114 | ||
| 115 | ret = of_mm_gpiochip_add(np, mm_gc); | |
| 116 | if (ret) | |
| 117 | goto err; | |
| 118 | return 0; | |
| 119 | err: | |
| 120 | kfree(u8_gc); | |
| 121 | return ret; | |
| 122 | } | |
| 123 | ||
| 124 | void __init simple_gpiochip_init(const char *compatible) | |
| 125 | { | |
| 126 | struct device_node *np; | |
| 127 | ||
| 128 | for_each_compatible_node(np, NULL, compatible) { | |
| 129 | int ret; | |
| 130 | struct resource r; | |
| 131 | ||
| 132 | ret = of_address_to_resource(np, 0, &r); | |
| 133 | if (ret) | |
| 134 | goto err; | |
| 135 | ||
| 136 | switch (resource_size(&r)) { | |
| 137 | case 1: | |
| 138 | ret = u8_simple_gpiochip_add(np); | |
| 139 | if (ret) | |
| 140 | goto err; | |
| 141 | break; | |
| 142 | default: | |
| 143 | /* | |
| 144 | * Whenever you need support for GPIO bank width > 1, | |
| 145 | * please just turn u8_ code into huge macros, and | |
| 146 | * construct needed uX_ code with it. | |
| 147 | */ | |
| 148 | ret = -ENOSYS; | |
| 149 | goto err; | |
| 150 | } | |
| 151 | continue; | |
| 152 | err: | |
| 153 | pr_err("%s: registration failed, status %d\n", | |
| 154 | np->full_name, ret); | |
| 155 | } | |
| 156 | } |