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