| Anton Vorontsov | 3d64de9 | 2008-12-18 19:37:26 +0300 | [diff] [blame] | 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> |
| 24 | #include <asm/prom.h> |
| 25 | #include "simple_gpio.h" |
| 26 | |
| 27 | struct u8_gpio_chip { |
| 28 | struct of_mm_gpio_chip mm_gc; |
| 29 | spinlock_t lock; |
| 30 | |
| 31 | /* shadowed data register to clear/set bits safely */ |
| 32 | u8 data; |
| 33 | }; |
| 34 | |
| 35 | static struct u8_gpio_chip *to_u8_gpio_chip(struct of_mm_gpio_chip *mm_gc) |
| 36 | { |
| 37 | return container_of(mm_gc, struct u8_gpio_chip, mm_gc); |
| 38 | } |
| 39 | |
| 40 | static u8 u8_pin2mask(unsigned int pin) |
| 41 | { |
| 42 | return 1 << (8 - 1 - pin); |
| 43 | } |
| 44 | |
| 45 | static int u8_gpio_get(struct gpio_chip *gc, unsigned int gpio) |
| 46 | { |
| 47 | struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc); |
| 48 | |
| 49 | return in_8(mm_gc->regs) & u8_pin2mask(gpio); |
| 50 | } |
| 51 | |
| 52 | static void u8_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val) |
| 53 | { |
| 54 | struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc); |
| 55 | struct u8_gpio_chip *u8_gc = to_u8_gpio_chip(mm_gc); |
| 56 | unsigned long flags; |
| 57 | |
| 58 | spin_lock_irqsave(&u8_gc->lock, flags); |
| 59 | |
| 60 | if (val) |
| 61 | u8_gc->data |= u8_pin2mask(gpio); |
| 62 | else |
| 63 | u8_gc->data &= ~u8_pin2mask(gpio); |
| 64 | |
| 65 | out_8(mm_gc->regs, u8_gc->data); |
| 66 | |
| 67 | spin_unlock_irqrestore(&u8_gc->lock, flags); |
| 68 | } |
| 69 | |
| 70 | static int u8_gpio_dir_in(struct gpio_chip *gc, unsigned int gpio) |
| 71 | { |
| 72 | return 0; |
| 73 | } |
| 74 | |
| 75 | static int u8_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val) |
| 76 | { |
| 77 | u8_gpio_set(gc, gpio, val); |
| 78 | return 0; |
| 79 | } |
| 80 | |
| 81 | static void u8_gpio_save_regs(struct of_mm_gpio_chip *mm_gc) |
| 82 | { |
| 83 | struct u8_gpio_chip *u8_gc = to_u8_gpio_chip(mm_gc); |
| 84 | |
| 85 | u8_gc->data = in_8(mm_gc->regs); |
| 86 | } |
| 87 | |
| 88 | static int __init u8_simple_gpiochip_add(struct device_node *np) |
| 89 | { |
| 90 | int ret; |
| 91 | struct u8_gpio_chip *u8_gc; |
| 92 | struct of_mm_gpio_chip *mm_gc; |
| 93 | struct of_gpio_chip *of_gc; |
| 94 | struct gpio_chip *gc; |
| 95 | |
| 96 | u8_gc = kzalloc(sizeof(*u8_gc), GFP_KERNEL); |
| 97 | if (!u8_gc) |
| 98 | return -ENOMEM; |
| 99 | |
| 100 | spin_lock_init(&u8_gc->lock); |
| 101 | |
| 102 | mm_gc = &u8_gc->mm_gc; |
| 103 | of_gc = &mm_gc->of_gc; |
| 104 | gc = &of_gc->gc; |
| 105 | |
| 106 | mm_gc->save_regs = u8_gpio_save_regs; |
| 107 | of_gc->gpio_cells = 2; |
| 108 | gc->ngpio = 8; |
| 109 | gc->direction_input = u8_gpio_dir_in; |
| 110 | gc->direction_output = u8_gpio_dir_out; |
| 111 | gc->get = u8_gpio_get; |
| 112 | gc->set = u8_gpio_set; |
| 113 | |
| 114 | ret = of_mm_gpiochip_add(np, mm_gc); |
| 115 | if (ret) |
| 116 | goto err; |
| 117 | return 0; |
| 118 | err: |
| 119 | kfree(u8_gc); |
| 120 | return ret; |
| 121 | } |
| 122 | |
| 123 | void __init simple_gpiochip_init(const char *compatible) |
| 124 | { |
| 125 | struct device_node *np; |
| 126 | |
| 127 | for_each_compatible_node(np, NULL, compatible) { |
| 128 | int ret; |
| 129 | struct resource r; |
| 130 | |
| 131 | ret = of_address_to_resource(np, 0, &r); |
| 132 | if (ret) |
| 133 | goto err; |
| 134 | |
| 135 | switch (resource_size(&r)) { |
| 136 | case 1: |
| 137 | ret = u8_simple_gpiochip_add(np); |
| 138 | if (ret) |
| 139 | goto err; |
| 140 | break; |
| 141 | default: |
| 142 | /* |
| 143 | * Whenever you need support for GPIO bank width > 1, |
| 144 | * please just turn u8_ code into huge macros, and |
| 145 | * construct needed uX_ code with it. |
| 146 | */ |
| 147 | ret = -ENOSYS; |
| 148 | goto err; |
| 149 | } |
| 150 | continue; |
| 151 | err: |
| 152 | pr_err("%s: registration failed, status %d\n", |
| 153 | np->full_name, ret); |
| 154 | } |
| 155 | } |