arch/mips/kernel/gpio_txx9.c

   1 /*
   2  * A gpio chip driver for TXx9 SoCs
   3  *
   4  * Copyright (C) 2008 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/init.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/gpio.h>
  14 #include <linux/errno.h>
  15 #include <linux/io.h>
  16 #include <asm/txx9pio.h>
  17
  18 static DEFINE_SPINLOCK(txx9_gpio_lock);
  19
  20 static struct txx9_pio_reg __iomem *txx9_pioptr;
  21
  22 static int txx9_gpio_get(struct gpio_chip *chip, unsigned int offset)
  23 {
  24         return __raw_readl(&txx9_pioptr->din) & (1 << offset);
  25 }
  26
  27 static void txx9_gpio_set_raw(unsigned int offset, int value)
  28 {
  29         u32 val;
  30         val = __raw_readl(&txx9_pioptr->dout);
  31         if (value)
  32                 val |= 1 << offset;
  33         else
  34                 val &= ~(1 << offset);
  35         __raw_writel(val, &txx9_pioptr->dout);
  36 }
  37
  38 static void txx9_gpio_set(struct gpio_chip *chip, unsigned int offset,
  39                           int value)
  40 {
  41         unsigned long flags;
  42         spin_lock_irqsave(&txx9_gpio_lock, flags);
  43         txx9_gpio_set_raw(offset, value);
  44         mmiowb();
  45         spin_unlock_irqrestore(&txx9_gpio_lock, flags);
  46 }
  47
  48 static int txx9_gpio_dir_in(struct gpio_chip *chip, unsigned int offset)
  49 {
  50         unsigned long flags;
  51         spin_lock_irqsave(&txx9_gpio_lock, flags);
  52         __raw_writel(__raw_readl(&txx9_pioptr->dir) & ~(1 << offset),
  53                      &txx9_pioptr->dir);
  54         mmiowb();
  55         spin_unlock_irqrestore(&txx9_gpio_lock, flags);
  56         return 0;
  57 }
  58
  59 static int txx9_gpio_dir_out(struct gpio_chip *chip, unsigned int offset,
  60                              int value)
  61 {
  62         unsigned long flags;
  63         spin_lock_irqsave(&txx9_gpio_lock, flags);
  64         txx9_gpio_set_raw(offset, value);
  65         __raw_writel(__raw_readl(&txx9_pioptr->dir) | (1 << offset),
  66                      &txx9_pioptr->dir);
  67         mmiowb();
  68         spin_unlock_irqrestore(&txx9_gpio_lock, flags);
  69         return 0;
  70 }
  71
  72 static struct gpio_chip txx9_gpio_chip = {
  73         .get = txx9_gpio_get,
  74         .set = txx9_gpio_set,
  75         .direction_input = txx9_gpio_dir_in,
  76         .direction_output = txx9_gpio_dir_out,
  77         .label = "TXx9",
  78 };
  79
  80 int __init txx9_gpio_init(unsigned long baseaddr,
  81                           unsigned int base, unsigned int num)
  82 {
  83         txx9_pioptr = ioremap(baseaddr, sizeof(struct txx9_pio_reg));
  84         if (!txx9_pioptr)
  85                 return -ENODEV;
  86         txx9_gpio_chip.base = base;
  87         txx9_gpio_chip.ngpio = num;
  88         return gpiochip_add(&txx9_gpio_chip);
  89 }