1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Simple Memory-Mapped GPIOs
5 * Copyright (c) MontaVista Software, Inc. 2008.
7 * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
10 #include <linux/init.h>
11 #include <linux/kernel.h>
12 #include <linux/spinlock.h>
13 #include <linux/types.h>
14 #include <linux/ioport.h>
17 #include <linux/of_gpio.h>
18 #include <linux/gpio/driver.h>
19 #include <linux/slab.h>
21 #include "simple_gpio.h"
24 struct of_mm_gpio_chip mm_gc;
27 /* shadowed data register to clear/set bits safely */
31 static u8 u8_pin2mask(unsigned int pin)
33 return 1 << (8 - 1 - pin);
36 static int u8_gpio_get(struct gpio_chip *gc, unsigned int gpio)
38 struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
40 return !!(in_8(mm_gc->regs) & u8_pin2mask(gpio));
43 static void u8_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
45 struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
46 struct u8_gpio_chip *u8_gc = gpiochip_get_data(gc);
49 spin_lock_irqsave(&u8_gc->lock, flags);
52 u8_gc->data |= u8_pin2mask(gpio);
54 u8_gc->data &= ~u8_pin2mask(gpio);
56 out_8(mm_gc->regs, u8_gc->data);
58 spin_unlock_irqrestore(&u8_gc->lock, flags);
61 static int u8_gpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
66 static int u8_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
68 u8_gpio_set(gc, gpio, val);
72 static void u8_gpio_save_regs(struct of_mm_gpio_chip *mm_gc)
74 struct u8_gpio_chip *u8_gc =
75 container_of(mm_gc, struct u8_gpio_chip, mm_gc);
77 u8_gc->data = in_8(mm_gc->regs);
80 static int __init u8_simple_gpiochip_add(struct device_node *np)
83 struct u8_gpio_chip *u8_gc;
84 struct of_mm_gpio_chip *mm_gc;
87 u8_gc = kzalloc(sizeof(*u8_gc), GFP_KERNEL);
91 spin_lock_init(&u8_gc->lock);
93 mm_gc = &u8_gc->mm_gc;
96 mm_gc->save_regs = u8_gpio_save_regs;
98 gc->direction_input = u8_gpio_dir_in;
99 gc->direction_output = u8_gpio_dir_out;
100 gc->get = u8_gpio_get;
101 gc->set = u8_gpio_set;
103 ret = of_mm_gpiochip_add_data(np, mm_gc, u8_gc);
112 void __init simple_gpiochip_init(const char *compatible)
114 struct device_node *np;
116 for_each_compatible_node(np, NULL, compatible) {
120 ret = of_address_to_resource(np, 0, &r);
124 switch (resource_size(&r)) {
126 ret = u8_simple_gpiochip_add(np);
132 * Whenever you need support for GPIO bank width > 1,
133 * please just turn u8_ code into huge macros, and
134 * construct needed uX_ code with it.
141 pr_err("%pOF: registration failed, status %d\n", np, ret);