arch/xtensa/variants/s6000/gpio.c

   1 /*
   2  * s6000 gpio driver
   3  *
   4  * Copyright (c) 2009 emlix GmbH
   5  * Authors:     Oskar Schirmer <os@emlix.com>
   6  *              Johannes Weiner <jw@emlix.com>
   7  */
   8 #include <linux/kernel.h>
   9 #include <linux/module.h>
  10 #include <linux/init.h>
  11 #include <linux/io.h>
  12 #include <linux/gpio.h>
  13
  14 #include <variant/hardware.h>
  15
  16 #define S6_GPIO_DATA            0x000
  17 #define S6_GPIO_IS              0x404
  18 #define S6_GPIO_IBE             0x408
  19 #define S6_GPIO_IEV             0x40C
  20 #define S6_GPIO_IE              0x410
  21 #define S6_GPIO_RIS             0x414
  22 #define S6_GPIO_MIS             0x418
  23 #define S6_GPIO_IC              0x41C
  24 #define S6_GPIO_AFSEL           0x420
  25 #define S6_GPIO_DIR             0x800
  26 #define S6_GPIO_BANK(nr)        ((nr) * 0x1000)
  27 #define S6_GPIO_MASK(nr)        (4 << (nr))
  28 #define S6_GPIO_OFFSET(nr) \
  29                 (S6_GPIO_BANK((nr) >> 3) + S6_GPIO_MASK((nr) & 7))
  30
  31 static int direction_input(struct gpio_chip *chip, unsigned int off)
  32 {
  33         writeb(0, S6_REG_GPIO + S6_GPIO_DIR + S6_GPIO_OFFSET(off));
  34         return 0;
  35 }
  36
  37 static int get(struct gpio_chip *chip, unsigned int off)
  38 {
  39         return readb(S6_REG_GPIO + S6_GPIO_DATA + S6_GPIO_OFFSET(off));
  40 }
  41
  42 static int direction_output(struct gpio_chip *chip, unsigned int off, int val)
  43 {
  44         unsigned rel = S6_GPIO_OFFSET(off);
  45         writeb(~0, S6_REG_GPIO + S6_GPIO_DIR + rel);
  46         writeb(val ? ~0 : 0, S6_REG_GPIO + S6_GPIO_DATA + rel);
  47         return 0;
  48 }
  49
  50 static void set(struct gpio_chip *chip, unsigned int off, int val)
  51 {
  52         writeb(val ? ~0 : 0, S6_REG_GPIO + S6_GPIO_DATA + S6_GPIO_OFFSET(off));
  53 }
  54
  55 static struct gpio_chip gpiochip = {
  56         .owner = THIS_MODULE,
  57         .direction_input = direction_input,
  58         .get = get,
  59         .direction_output = direction_output,
  60         .set = set,
  61         .base = 0,
  62         .ngpio = 24,
  63         .can_sleep = 0, /* no blocking io needed */
  64         .exported = 0, /* no exporting to userspace */
  65 };
  66
  67 int s6_gpio_init(void)
  68 {
  69         return gpiochip_add(&gpiochip);
  70 }