Logo Search packages:      
Sourcecode: linux version File versions  Download package

gpio.c

/* linux/arch/arm/plat-s3c/gpio.c
 *
 * Copyright 2008 Simtec Electronics
 *    Ben Dooks <ben@simtec.co.uk>
 *    http://armlinux.simtec.co.uk/
 *
 * S3C series GPIO core
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
*/

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/gpio.h>

#include <mach/gpio-core.h>

#ifdef CONFIG_S3C_GPIO_TRACK
struct s3c_gpio_chip *s3c_gpios[S3C_GPIO_END];

static __init void s3c_gpiolib_track(struct s3c_gpio_chip *chip)
{
      unsigned int gpn;
      int i;

      gpn = chip->chip.base;
      for (i = 0; i < chip->chip.ngpio; i++, gpn++) {
            BUG_ON(gpn >= ARRAY_SIZE(s3c_gpios));
            s3c_gpios[gpn] = chip;
      }
}
#endif /* CONFIG_S3C_GPIO_TRACK */

/* Default routines for controlling GPIO, based on the original S3C24XX
 * GPIO functions which deal with the case where each gpio bank of the
 * chip is as following:
 *
 * base + 0x00: Control register, 2 bits per gpio
 *            gpio n: 2 bits starting at (2*n)
 *          00 = input, 01 = output, others mean special-function
 * base + 0x04: Data register, 1 bit per gpio
 *          bit n: data bit n
*/

static int s3c_gpiolib_input(struct gpio_chip *chip, unsigned offset)
{
      struct s3c_gpio_chip *ourchip = to_s3c_gpio(chip);
      void __iomem *base = ourchip->base;
      unsigned long flags;
      unsigned long con;

      local_irq_save(flags);

      con = __raw_readl(base + 0x00);
      con &= ~(3 << (offset * 2));

      __raw_writel(con, base + 0x00);

      local_irq_restore(flags);
      return 0;
}

static int s3c_gpiolib_output(struct gpio_chip *chip,
                        unsigned offset, int value)
{
      struct s3c_gpio_chip *ourchip = to_s3c_gpio(chip);
      void __iomem *base = ourchip->base;
      unsigned long flags;
      unsigned long dat;
      unsigned long con;

      local_irq_save(flags);

      dat = __raw_readl(base + 0x04);
      dat &= ~(1 << offset);
      if (value)
            dat |= 1 << offset;
      __raw_writel(dat, base + 0x04);

      con = __raw_readl(base + 0x00);
      con &= ~(3 << (offset * 2));
      con |= 1 << (offset * 2);

      __raw_writel(con, base + 0x00);
      __raw_writel(dat, base + 0x04);

      local_irq_restore(flags);
      return 0;
}

static void s3c_gpiolib_set(struct gpio_chip *chip,
                      unsigned offset, int value)
{
      struct s3c_gpio_chip *ourchip = to_s3c_gpio(chip);
      void __iomem *base = ourchip->base;
      unsigned long flags;
      unsigned long dat;

      local_irq_save(flags);

      dat = __raw_readl(base + 0x04);
      dat &= ~(1 << offset);
      if (value)
            dat |= 1 << offset;
      __raw_writel(dat, base + 0x04);

      local_irq_restore(flags);
}

static int s3c_gpiolib_get(struct gpio_chip *chip, unsigned offset)
{
      struct s3c_gpio_chip *ourchip = to_s3c_gpio(chip);
      unsigned long val;

      val = __raw_readl(ourchip->base + 0x04);
      val >>= offset;
      val &= 1;

      return val;
}

__init void s3c_gpiolib_add(struct s3c_gpio_chip *chip)
{
      struct gpio_chip *gc = &chip->chip;
      int ret;

      BUG_ON(!chip->base);
      BUG_ON(!gc->label);
      BUG_ON(!gc->ngpio);

      if (!gc->direction_input)
            gc->direction_input = s3c_gpiolib_input;
      if (!gc->direction_output)
            gc->direction_output = s3c_gpiolib_output;
      if (!gc->set)
            gc->set = s3c_gpiolib_set;
      if (!gc->get)
            gc->get = s3c_gpiolib_get;

#ifdef CONFIG_PM
      if (chip->pm != NULL) {
            if (!chip->pm->save || !chip->pm->resume)
                  printk(KERN_ERR "gpio: %s has missing PM functions\n",
                         gc->label);
      } else
            printk(KERN_ERR "gpio: %s has no PM function\n", gc->label);
#endif

      /* gpiochip_add() prints own failure message on error. */
      ret = gpiochip_add(gc);
      if (ret >= 0)
            s3c_gpiolib_track(chip);
}

Generated by  Doxygen 1.6.0   Back to index