LXR linux/arch/powerpc/sysdev/simple

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Simple Memory-Mapped GPIOs
   4 *
   5 * Copyright (c) MontaVista Software, Inc. 2008.
   6 *
   7 * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
   8 */
   9
  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>
  15#include <linux/io.h>
  16#include <linux/of.h>
  17#include <linux/of_gpio.h>
  18#include <linux/gpio/driver.h>
  19#include <linux/slab.h>
  20#include <asm/prom.h>
  21#include "simple_gpio.h"
  22
  23struct u8_gpio_chip {
  24        struct of_mm_gpio_chip mm_gc;
  25        spinlock_t lock;
  26
  27        /* shadowed data register to clear/set bits safely */
  28        u8 data;
  29};
  30
  31static u8 u8_pin2mask(unsigned int pin)
  32{
  33        return 1 << (8 - 1 - pin);
  34}
  35
  36static int u8_gpio_get(struct gpio_chip *gc, unsigned int gpio)
  37{
  38        struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
  39
  40        return !!(in_8(mm_gc->regs) & u8_pin2mask(gpio));
  41}
  42
  43static void u8_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
  44{
  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);
  47        unsigned long flags;
  48
  49        spin_lock_irqsave(&u8_gc->lock, flags);
  50
  51        if (val)
  52                u8_gc->data |= u8_pin2mask(gpio);
  53        else
  54                u8_gc->data &= ~u8_pin2mask(gpio);
  55
  56        out_8(mm_gc->regs, u8_gc->data);
  57
  58        spin_unlock_irqrestore(&u8_gc->lock, flags);
  59}
  60
  61static int u8_gpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
  62{
  63        return 0;
  64}
  65
  66static int u8_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
  67{
  68        u8_gpio_set(gc, gpio, val);
  69        return 0;
  70}
  71
  72static void u8_gpio_save_regs(struct of_mm_gpio_chip *mm_gc)
  73{
  74        struct u8_gpio_chip *u8_gc =
  75                container_of(mm_gc, struct u8_gpio_chip, mm_gc);
  76
  77        u8_gc->data = in_8(mm_gc->regs);
  78}
  79
  80static int __init u8_simple_gpiochip_add(struct device_node *np)
  81{
  82        int ret;
  83        struct u8_gpio_chip *u8_gc;
  84        struct of_mm_gpio_chip *mm_gc;
  85        struct gpio_chip *gc;
  86
  87        u8_gc = kzalloc(sizeof(*u8_gc), GFP_KERNEL);
  88        if (!u8_gc)
  89                return -ENOMEM;
  90
  91        spin_lock_init(&u8_gc->lock);
  92
  93        mm_gc = &u8_gc->mm_gc;
  94        gc = &mm_gc->gc;
  95
  96        mm_gc->save_regs = u8_gpio_save_regs;
  97        gc->ngpio = 8;
  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;
 102
 103        ret = of_mm_gpiochip_add_data(np, mm_gc, u8_gc);
 104        if (ret)
 105                goto err;
 106        return 0;
 107err:
 108        kfree(u8_gc);
 109        return ret;
 110}
 111
 112void __init simple_gpiochip_init(const char *compatible)
 113{
 114        struct device_node *np;
 115
 116        for_each_compatible_node(np, NULL, compatible) {
 117                int ret;
 118                struct resource r;
 119
 120                ret = of_address_to_resource(np, 0, &r);
 121                if (ret)
 122                        goto err;
 123
 124                switch (resource_size(&r)) {
 125                case 1:
 126                        ret = u8_simple_gpiochip_add(np);
 127                        if (ret)
 128                                goto err;
 129                        break;
 130                default:
 131                        /*
 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.
 135                         */
 136                        ret = -ENOSYS;
 137                        goto err;
 138                }
 139                continue;
 140err:
 141                pr_err("%pOF: registration failed, status %d\n", np, ret);
 142        }
 143}
 144