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> | |
| 3d64de9c AV |
16 | #include <linux/spinlock.h> |
| 17 | #include <linux/types.h> | |
| 18 | #include <linux/ioport.h> | |
| 19 | #include <linux/io.h> | |
| 20 | #include <linux/of.h> | |
| 21 | #include <linux/of_gpio.h> | |
| 937daafc | 22 | #include <linux/gpio/driver.h> |
| 5a0e3ad6 | 23 | #include <linux/slab.h> |
| 3d64de9c AV |
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 | ||
| 3d64de9c AV |
35 | static u8 u8_pin2mask(unsigned int pin) |
| 36 | { | |
| 37 | return 1 << (8 - 1 - pin); | |
| 38 | } | |
| 39 | ||
| 40 | static int u8_gpio_get(struct gpio_chip *gc, unsigned int gpio) | |
| 41 | { | |
| 42 | struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc); | |
| 43 | ||
| a4ce4b8d | 44 | return !!(in_8(mm_gc->regs) & u8_pin2mask(gpio)); |
| 3d64de9c AV |
45 | } |
| 46 | ||
| 47 | static void u8_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val) | |
| 48 | { | |
| 49 | struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc); | |
| 937daafc | 50 | struct u8_gpio_chip *u8_gc = gpiochip_get_data(gc); |
| 3d64de9c AV |
51 | unsigned long flags; |
| 52 | ||
| 53 | spin_lock_irqsave(&u8_gc->lock, flags); | |
| 54 | ||
| 55 | if (val) | |
| 56 | u8_gc->data |= u8_pin2mask(gpio); | |
| 57 | else | |
| 58 | u8_gc->data &= ~u8_pin2mask(gpio); | |
| 59 | ||
| 60 | out_8(mm_gc->regs, u8_gc->data); | |
| 61 | ||
| 62 | spin_unlock_irqrestore(&u8_gc->lock, flags); | |
| 63 | } | |
| 64 | ||
| 65 | static int u8_gpio_dir_in(struct gpio_chip *gc, unsigned int gpio) | |
| 66 | { | |
| 67 | return 0; | |
| 68 | } | |
| 69 | ||
| 70 | static int u8_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val) | |
| 71 | { | |
| 72 | u8_gpio_set(gc, gpio, val); | |
| 73 | return 0; | |
| 74 | } | |
| 75 | ||
| 76 | static void u8_gpio_save_regs(struct of_mm_gpio_chip *mm_gc) | |
| 77 | { | |
| 937daafc | 78 | struct u8_gpio_chip *u8_gc = gpiochip_get_data(&mm_gc->gc); |
| 3d64de9c AV |
79 | |
| 80 | u8_gc->data = in_8(mm_gc->regs); | |
| 81 | } | |
| 82 | ||
| 83 | static int __init u8_simple_gpiochip_add(struct device_node *np) | |
| 84 | { | |
| 85 | int ret; | |
| 86 | struct u8_gpio_chip *u8_gc; | |
| 87 | struct of_mm_gpio_chip *mm_gc; | |
| 3d64de9c AV |
88 | struct gpio_chip *gc; |
| 89 | ||
| 90 | u8_gc = kzalloc(sizeof(*u8_gc), GFP_KERNEL); | |
| 91 | if (!u8_gc) | |
| 92 | return -ENOMEM; | |
| 93 | ||
| 94 | spin_lock_init(&u8_gc->lock); | |
| 95 | ||
| 96 | mm_gc = &u8_gc->mm_gc; | |
| a19e3da5 | 97 | gc = &mm_gc->gc; |
| 3d64de9c AV |
98 | |
| 99 | mm_gc->save_regs = u8_gpio_save_regs; | |
| 3d64de9c AV |
100 | gc->ngpio = 8; |
| 101 | gc->direction_input = u8_gpio_dir_in; | |
| 102 | gc->direction_output = u8_gpio_dir_out; | |
| 103 | gc->get = u8_gpio_get; | |
| 104 | gc->set = u8_gpio_set; | |
| 105 | ||
| 937daafc | 106 | ret = of_mm_gpiochip_add_data(np, mm_gc, u8_gc); |
| 3d64de9c AV |
107 | if (ret) |
| 108 | goto err; | |
| 109 | return 0; | |
| 110 | err: | |
| 111 | kfree(u8_gc); | |
| 112 | return ret; | |
| 113 | } | |
| 114 | ||
| 115 | void __init simple_gpiochip_init(const char *compatible) | |
| 116 | { | |
| 117 | struct device_node *np; | |
| 118 | ||
| 119 | for_each_compatible_node(np, NULL, compatible) { | |
| 120 | int ret; | |
| 121 | struct resource r; | |
| 122 | ||
| 123 | ret = of_address_to_resource(np, 0, &r); | |
| 124 | if (ret) | |
| 125 | goto err; | |
| 126 | ||
| 127 | switch (resource_size(&r)) { | |
| 128 | case 1: | |
| 129 | ret = u8_simple_gpiochip_add(np); | |
| 130 | if (ret) | |
| 131 | goto err; | |
| 132 | break; | |
| 133 | default: | |
| 134 | /* | |
| 135 | * Whenever you need support for GPIO bank width > 1, | |
| 136 | * please just turn u8_ code into huge macros, and | |
| 137 | * construct needed uX_ code with it. | |
| 138 | */ | |
| 139 | ret = -ENOSYS; | |
| 140 | goto err; | |
| 141 | } | |
| 142 | continue; | |
| 143 | err: | |
| 144 | pr_err("%s: registration failed, status %d\n", | |
| 145 | np->full_name, ret); | |
| 146 | } | |
| 147 | } |