2 * Simple Memory-Mapped GPIOs
4 * Copyright (c) MontaVista Software, Inc. 2008.
6 * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
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.
14 #include <linux/init.h>
15 #include <linux/kernel.h>
16 #include <linux/spinlock.h>
17 #include <linux/types.h>
18 #include <linux/ioport.h>
21 #include <linux/of_gpio.h>
22 #include <linux/gpio/driver.h>
23 #include <linux/slab.h>
25 #include "simple_gpio.h"
28 struct of_mm_gpio_chip mm_gc;
31 /* shadowed data register to clear/set bits safely */
35 static u8 u8_pin2mask(unsigned int pin)
37 return 1 << (8 - 1 - pin);
40 static int u8_gpio_get(struct gpio_chip *gc, unsigned int gpio)
42 struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
44 return !!(in_8(mm_gc->regs) & u8_pin2mask(gpio));
47 static void u8_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
49 struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
50 struct u8_gpio_chip *u8_gc = gpiochip_get_data(gc);
53 spin_lock_irqsave(&u8_gc->lock, flags);
56 u8_gc->data |= u8_pin2mask(gpio);
58 u8_gc->data &= ~u8_pin2mask(gpio);
60 out_8(mm_gc->regs, u8_gc->data);
62 spin_unlock_irqrestore(&u8_gc->lock, flags);
65 static int u8_gpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
70 static int u8_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
72 u8_gpio_set(gc, gpio, val);
76 static void u8_gpio_save_regs(struct of_mm_gpio_chip *mm_gc)
78 struct u8_gpio_chip *u8_gc = gpiochip_get_data(&mm_gc->gc);
80 u8_gc->data = in_8(mm_gc->regs);
83 static int __init u8_simple_gpiochip_add(struct device_node *np)
86 struct u8_gpio_chip *u8_gc;
87 struct of_mm_gpio_chip *mm_gc;
90 u8_gc = kzalloc(sizeof(*u8_gc), GFP_KERNEL);
94 spin_lock_init(&u8_gc->lock);
96 mm_gc = &u8_gc->mm_gc;
99 mm_gc->save_regs = u8_gpio_save_regs;
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;
106 ret = of_mm_gpiochip_add_data(np, mm_gc, u8_gc);
115 void __init simple_gpiochip_init(const char *compatible)
117 struct device_node *np;
119 for_each_compatible_node(np, NULL, compatible) {
123 ret = of_address_to_resource(np, 0, &r);
127 switch (resource_size(&r)) {
129 ret = u8_simple_gpiochip_add(np);
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.
144 pr_err("%s: registration failed, status %d\n",