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gpio.c

/*
 * arch/arm/mach-ks8695/gpio.c
 *
 * Copyright (C) 2006 Andrew Victor
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/module.h>
#include <linux/io.h>

#include <mach/hardware.h>
#include <asm/mach/irq.h>

#include <mach/regs-gpio.h>
#include <mach/gpio.h>

/*
 * Configure a GPIO line for either GPIO function, or its internal
 * function (Interrupt, Timer, etc).
 */
static void __init_or_module ks8695_gpio_mode(unsigned int pin, short gpio)
{
      unsigned int enable[] = { IOPC_IOEINT0EN, IOPC_IOEINT1EN, IOPC_IOEINT2EN, IOPC_IOEINT3EN, IOPC_IOTIM0EN, IOPC_IOTIM1EN };
      unsigned long x, flags;

      if (pin > KS8695_GPIO_5)      /* only GPIO 0..5 have internal functions */
            return;

      local_irq_save(flags);

      x = __raw_readl(KS8695_GPIO_VA + KS8695_IOPC);
      if (gpio)               /* GPIO: set bit to 0 */
            x &= ~enable[pin];
      else                    /* Internal function: set bit to 1 */
            x |= enable[pin];
      __raw_writel(x, KS8695_GPIO_VA + KS8695_IOPC);

      local_irq_restore(flags);
}


static unsigned short gpio_irq[] = { KS8695_IRQ_EXTERN0, KS8695_IRQ_EXTERN1, KS8695_IRQ_EXTERN2, KS8695_IRQ_EXTERN3 };

/*
 * Configure GPIO pin as external interrupt source.
 */
int __init_or_module ks8695_gpio_interrupt(unsigned int pin, unsigned int type)
{
      unsigned long x, flags;

      if (pin > KS8695_GPIO_3)      /* only GPIO 0..3 can generate IRQ */
            return -EINVAL;

      local_irq_save(flags);

      /* set pin as input */
      x = __raw_readl(KS8695_GPIO_VA + KS8695_IOPM);
      x &= ~IOPM(pin);
      __raw_writel(x, KS8695_GPIO_VA + KS8695_IOPM);

      local_irq_restore(flags);

      /* Set IRQ triggering type */
      set_irq_type(gpio_irq[pin], type);

      /* enable interrupt mode */
      ks8695_gpio_mode(pin, 0);

      return 0;
}
EXPORT_SYMBOL(ks8695_gpio_interrupt);



/* .... Generic GPIO interface .............................................. */

/*
 * Configure the GPIO line as an input.
 */
int __init_or_module gpio_direction_input(unsigned int pin)
{
      unsigned long x, flags;

      if (pin > KS8695_GPIO_15)
            return -EINVAL;

      /* set pin to GPIO mode */
      ks8695_gpio_mode(pin, 1);

      local_irq_save(flags);

      /* set pin as input */
      x = __raw_readl(KS8695_GPIO_VA + KS8695_IOPM);
      x &= ~IOPM(pin);
      __raw_writel(x, KS8695_GPIO_VA + KS8695_IOPM);

      local_irq_restore(flags);

      return 0;
}
EXPORT_SYMBOL(gpio_direction_input);


/*
 * Configure the GPIO line as an output, with default state.
 */
int __init_or_module gpio_direction_output(unsigned int pin, unsigned int state)
{
      unsigned long x, flags;

      if (pin > KS8695_GPIO_15)
            return -EINVAL;

      /* set pin to GPIO mode */
      ks8695_gpio_mode(pin, 1);

      local_irq_save(flags);

      /* set line state */
      x = __raw_readl(KS8695_GPIO_VA + KS8695_IOPD);
      if (state)
            x |= IOPD(pin);
      else
            x &= ~IOPD(pin);
      __raw_writel(x, KS8695_GPIO_VA + KS8695_IOPD);

      /* set pin as output */
      x = __raw_readl(KS8695_GPIO_VA + KS8695_IOPM);
      x |= IOPM(pin);
      __raw_writel(x, KS8695_GPIO_VA + KS8695_IOPM);

      local_irq_restore(flags);

      return 0;
}
EXPORT_SYMBOL(gpio_direction_output);


/*
 * Set the state of an output GPIO line.
 */
void gpio_set_value(unsigned int pin, unsigned int state)
{
      unsigned long x, flags;

      if (pin > KS8695_GPIO_15)
            return;

      local_irq_save(flags);

      /* set output line state */
      x = __raw_readl(KS8695_GPIO_VA + KS8695_IOPD);
      if (state)
            x |= IOPD(pin);
      else
            x &= ~IOPD(pin);
      __raw_writel(x, KS8695_GPIO_VA + KS8695_IOPD);

      local_irq_restore(flags);
}
EXPORT_SYMBOL(gpio_set_value);


/*
 * Read the state of a GPIO line.
 */
int gpio_get_value(unsigned int pin)
{
      unsigned long x;

      if (pin > KS8695_GPIO_15)
            return -EINVAL;

      x = __raw_readl(KS8695_GPIO_VA + KS8695_IOPD);
      return (x & IOPD(pin)) != 0;
}
EXPORT_SYMBOL(gpio_get_value);


/*
 * Map GPIO line to IRQ number.
 */
int gpio_to_irq(unsigned int pin)
{
      if (pin > KS8695_GPIO_3)      /* only GPIO 0..3 can generate IRQ */
            return -EINVAL;

      return gpio_irq[pin];
}
EXPORT_SYMBOL(gpio_to_irq);


/*
 * Map IRQ number to GPIO line.
 */
int irq_to_gpio(unsigned int irq)
{
      if ((irq < KS8695_IRQ_EXTERN0) || (irq > KS8695_IRQ_EXTERN3))
            return -EINVAL;

      return (irq - KS8695_IRQ_EXTERN0);
}
EXPORT_SYMBOL(irq_to_gpio);


/* .... Debug interface ..................................................... */

#ifdef CONFIG_DEBUG_FS

static int ks8695_gpio_show(struct seq_file *s, void *unused)
{
      unsigned int enable[] = { IOPC_IOEINT0EN, IOPC_IOEINT1EN, IOPC_IOEINT2EN, IOPC_IOEINT3EN, IOPC_IOTIM0EN, IOPC_IOTIM1EN };
      unsigned int intmask[] = { IOPC_IOEINT0TM, IOPC_IOEINT1TM, IOPC_IOEINT2TM, IOPC_IOEINT3TM };
      unsigned long mode, ctrl, data;
      int i;

      mode = __raw_readl(KS8695_GPIO_VA + KS8695_IOPM);
      ctrl = __raw_readl(KS8695_GPIO_VA + KS8695_IOPC);
      data = __raw_readl(KS8695_GPIO_VA + KS8695_IOPD);

      seq_printf(s, "Pin\tI/O\tFunction\tState\n\n");

      for (i = KS8695_GPIO_0; i <= KS8695_GPIO_15 ; i++) {
            seq_printf(s, "%i:\t", i);

            seq_printf(s, "%s\t", (mode & IOPM(i)) ? "Output" : "Input");

            if (i <= KS8695_GPIO_3) {
                  if (ctrl & enable[i]) {
                        seq_printf(s, "EXT%i ", i);

                        switch ((ctrl & intmask[i]) >> (4 * i)) {
                              case IOPC_TM_LOW:
                                    seq_printf(s, "(Low)");       break;
                              case IOPC_TM_HIGH:
                                    seq_printf(s, "(High)");      break;
                              case IOPC_TM_RISING:
                                    seq_printf(s, "(Rising)");    break;
                              case IOPC_TM_FALLING:
                                    seq_printf(s, "(Falling)");   break;
                              case IOPC_TM_EDGE:
                                    seq_printf(s, "(Edges)");     break;
                        }
                  }
                  else
                        seq_printf(s, "GPIO\t");
            }
            else if (i <= KS8695_GPIO_5) {
                  if (ctrl & enable[i])
                        seq_printf(s, "TOUT%i\t", i - KS8695_GPIO_4);
                  else
                        seq_printf(s, "GPIO\t");
            }
            else
                  seq_printf(s, "GPIO\t");

            seq_printf(s, "\t");

            seq_printf(s, "%i\n", (data & IOPD(i)) ? 1 : 0);
      }
      return 0;
}

static int ks8695_gpio_open(struct inode *inode, struct file *file)
{
      return single_open(file, ks8695_gpio_show, NULL);
}

static const struct file_operations ks8695_gpio_operations = {
      .open       = ks8695_gpio_open,
      .read       = seq_read,
      .llseek           = seq_lseek,
      .release    = single_release,
};

static int __init ks8695_gpio_debugfs_init(void)
{
      /* /sys/kernel/debug/ks8695_gpio */
      (void) debugfs_create_file("ks8695_gpio", S_IFREG | S_IRUGO, NULL, NULL, &ks8695_gpio_operations);
      return 0;
}
postcore_initcall(ks8695_gpio_debugfs_init);

#endif

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