arch/arm/plat-samsung/gpio.c

   1 /* linux/arch/arm/plat-s3c/gpio.c
   2  *
   3  * Copyright 2008 Simtec Electronics
   4  *      Ben Dooks <ben@simtec.co.uk>
   5  *      http://armlinux.simtec.co.uk/
   6  *
   7  * S3C series GPIO core
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12 */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16 #include <linux/io.h>
  17 #include <linux/gpio.h>
  18 #include <linux/spinlock.h>
  19
  20 #include <plat/gpio-core.h>
  21
  22 #ifdef CONFIG_S3C_GPIO_TRACK
  23 struct s3c_gpio_chip *s3c_gpios[S3C_GPIO_END];
  24
  25 static __init void s3c_gpiolib_track(struct s3c_gpio_chip *chip)
  26 {
  27         unsigned int gpn;
  28         int i;
  29
  30         gpn = chip->chip.base;
  31         for (i = 0; i < chip->chip.ngpio; i++, gpn++) {
  32                 BUG_ON(gpn >= ARRAY_SIZE(s3c_gpios));
  33                 s3c_gpios[gpn] = chip;
  34         }
  35 }
  36 #endif /* CONFIG_S3C_GPIO_TRACK */
  37
  38 /* Default routines for controlling GPIO, based on the original S3C24XX
  39  * GPIO functions which deal with the case where each gpio bank of the
  40  * chip is as following:
  41  *
  42  * base + 0x00: Control register, 2 bits per gpio
  43  *              gpio n: 2 bits starting at (2*n)
  44  *              00 = input, 01 = output, others mean special-function
  45  * base + 0x04: Data register, 1 bit per gpio
  46  *              bit n: data bit n
  47 */
  48
  49 static int s3c_gpiolib_input(struct gpio_chip *chip, unsigned offset)
  50 {
  51         struct s3c_gpio_chip *ourchip = to_s3c_gpio(chip);
  52         void __iomem *base = ourchip->base;
  53         unsigned long flags;
  54         unsigned long con;
  55
  56         s3c_gpio_lock(ourchip, flags);
  57
  58         con = __raw_readl(base + 0x00);
  59         con &= ~(3 << (offset * 2));
  60
  61         __raw_writel(con, base + 0x00);
  62
  63         s3c_gpio_unlock(ourchip, flags);
  64         return 0;
  65 }
  66
  67 static int s3c_gpiolib_output(struct gpio_chip *chip,
  68                               unsigned offset, int value)
  69 {
  70         struct s3c_gpio_chip *ourchip = to_s3c_gpio(chip);
  71         void __iomem *base = ourchip->base;
  72         unsigned long flags;
  73         unsigned long dat;
  74         unsigned long con;
  75
  76         s3c_gpio_lock(ourchip, flags);
  77
  78         dat = __raw_readl(base + 0x04);
  79         dat &= ~(1 << offset);
  80         if (value)
  81                 dat |= 1 << offset;
  82         __raw_writel(dat, base + 0x04);
  83
  84         con = __raw_readl(base + 0x00);
  85         con &= ~(3 << (offset * 2));
  86         con |= 1 << (offset * 2);
  87
  88         __raw_writel(con, base + 0x00);
  89         __raw_writel(dat, base + 0x04);
  90
  91         s3c_gpio_unlock(ourchip, flags);
  92         return 0;
  93 }
  94
  95 static void s3c_gpiolib_set(struct gpio_chip *chip,
  96                             unsigned offset, int value)
  97 {
  98         struct s3c_gpio_chip *ourchip = to_s3c_gpio(chip);
  99         void __iomem *base = ourchip->base;
 100         unsigned long flags;
 101         unsigned long dat;
 102
 103         s3c_gpio_lock(ourchip, flags);
 104
 105         dat = __raw_readl(base + 0x04);
 106         dat &= ~(1 << offset);
 107         if (value)
 108                 dat |= 1 << offset;
 109         __raw_writel(dat, base + 0x04);
 110
 111         s3c_gpio_unlock(ourchip, flags);
 112 }
 113
 114 static int s3c_gpiolib_get(struct gpio_chip *chip, unsigned offset)
 115 {
 116         struct s3c_gpio_chip *ourchip = to_s3c_gpio(chip);
 117         unsigned long val;
 118
 119         val = __raw_readl(ourchip->base + 0x04);
 120         val >>= offset;
 121         val &= 1;
 122
 123         return val;
 124 }
 125
 126 __init void s3c_gpiolib_add(struct s3c_gpio_chip *chip)
 127 {
 128         struct gpio_chip *gc = &chip->chip;
 129         int ret;
 130
 131         BUG_ON(!chip->base);
 132         BUG_ON(!gc->label);
 133         BUG_ON(!gc->ngpio);
 134
 135         spin_lock_init(&chip->lock);
 136
 137         if (!gc->direction_input)
 138                 gc->direction_input = s3c_gpiolib_input;
 139         if (!gc->direction_output)
 140                 gc->direction_output = s3c_gpiolib_output;
 141         if (!gc->set)
 142                 gc->set = s3c_gpiolib_set;
 143         if (!gc->get)
 144                 gc->get = s3c_gpiolib_get;
 145
 146 #ifdef CONFIG_PM
 147         if (chip->pm != NULL) {
 148                 if (!chip->pm->save || !chip->pm->resume)
 149                         printk(KERN_ERR "gpio: %s has missing PM functions\n",
 150                                gc->label);
 151         } else
 152                 printk(KERN_ERR "gpio: %s has no PM function\n", gc->label);
 153 #endif
 154
 155         /* gpiochip_add() prints own failure message on error. */
 156         ret = gpiochip_add(gc);
 157         if (ret >= 0)
 158                 s3c_gpiolib_track(chip);
 159 }