arch/arm/plat-s3c/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
  19 #include <plat/gpio-core.h>
  20
  21 #ifdef CONFIG_S3C_GPIO_TRACK
  22 struct s3c_gpio_chip *s3c_gpios[S3C_GPIO_END];
  23
  24 static __init void s3c_gpiolib_track(struct s3c_gpio_chip *chip)
  25 {
  26         unsigned int gpn;
  27         int i;
  28
  29         gpn = chip->chip.base;
  30         for (i = 0; i < chip->chip.ngpio; i++, gpn++) {
  31                 BUG_ON(gpn > ARRAY_SIZE(s3c_gpios));
  32                 s3c_gpios[gpn] = chip;
  33         }
  34 }
  35 #endif /* CONFIG_S3C_GPIO_TRACK */
  36
  37 /* Default routines for controlling GPIO, based on the original S3C24XX
  38  * GPIO functions which deal with the case where each gpio bank of the
  39  * chip is as following:
  40  *
  41  * base + 0x00: Control register, 2 bits per gpio
  42  *              gpio n: 2 bits starting at (2*n)
  43  *              00 = input, 01 = output, others mean special-function
  44  * base + 0x04: Data register, 1 bit per gpio
  45  *              bit n: data bit n
  46 */
  47
  48 static int s3c_gpiolib_input(struct gpio_chip *chip, unsigned offset)
  49 {
  50         struct s3c_gpio_chip *ourchip = to_s3c_gpio(chip);
  51         void __iomem *base = ourchip->base;
  52         unsigned long flags;
  53         unsigned long con;
  54
  55         local_irq_save(flags);
  56
  57         con = __raw_readl(base + 0x00);
  58         con &= ~(3 << (offset * 2));
  59
  60         __raw_writel(con, base + 0x00);
  61
  62         local_irq_restore(flags);
  63         return 0;
  64 }
  65
  66 static int s3c_gpiolib_output(struct gpio_chip *chip,
  67                               unsigned offset, int value)
  68 {
  69         struct s3c_gpio_chip *ourchip = to_s3c_gpio(chip);
  70         void __iomem *base = ourchip->base;
  71         unsigned long flags;
  72         unsigned long dat;
  73         unsigned long con;
  74
  75         local_irq_save(flags);
  76
  77         dat = __raw_readl(base + 0x04);
  78         dat &= ~(1 << offset);
  79         if (value)
  80                 dat |= 1 << offset;
  81         __raw_writel(dat, base + 0x04);
  82
  83         con = __raw_readl(base + 0x00);
  84         con &= ~(3 << (offset * 2));
  85         con |= 1 << (offset * 2);
  86
  87         __raw_writel(con, base + 0x00);
  88         __raw_writel(dat, base + 0x04);
  89
  90         local_irq_restore(flags);
  91         return 0;
  92 }
  93
  94 static void s3c_gpiolib_set(struct gpio_chip *chip,
  95                             unsigned offset, int value)
  96 {
  97         struct s3c_gpio_chip *ourchip = to_s3c_gpio(chip);
  98         void __iomem *base = ourchip->base;
  99         unsigned long flags;
 100         unsigned long dat;
 101
 102         local_irq_save(flags);
 103
 104         dat = __raw_readl(base + 0x04);
 105         dat &= ~(1 << offset);
 106         if (value)
 107                 dat |= 1 << offset;
 108         __raw_writel(dat, base + 0x04);
 109
 110         local_irq_restore(flags);
 111 }
 112
 113 static int s3c_gpiolib_get(struct gpio_chip *chip, unsigned offset)
 114 {
 115         struct s3c_gpio_chip *ourchip = to_s3c_gpio(chip);
 116         unsigned long val;
 117
 118         val = __raw_readl(ourchip->base + 0x04);
 119         val >>= offset;
 120         val &= 1;
 121
 122         return val;
 123 }
 124
 125 __init void s3c_gpiolib_add(struct s3c_gpio_chip *chip)
 126 {
 127         struct gpio_chip *gc = &chip->chip;
 128         int ret;
 129
 130         BUG_ON(!chip->base);
 131         BUG_ON(!gc->label);
 132         BUG_ON(!gc->ngpio);
 133
 134         if (!gc->direction_input)
 135                 gc->direction_input = s3c_gpiolib_input;
 136         if (!gc->direction_output)
 137                 gc->direction_output = s3c_gpiolib_output;
 138         if (!gc->set)
 139                 gc->set = s3c_gpiolib_set;
 140         if (!gc->get)
 141                 gc->get = s3c_gpiolib_get;
 142
 143         /* gpiochip_add() prints own failure message on error. */
 144         ret = gpiochip_add(gc);
 145         if (ret >= 0)
 146                 s3c_gpiolib_track(chip);
 147 }