drivers/misc/c2port/c2port-duramar2150.c

   1 /*
   2  *  Silicon Labs C2 port Linux support for Eurotech Duramar 2150
   3  *
   4  *  Copyright (c) 2008 Rodolfo Giometti <giometti@linux.it>
   5  *  Copyright (c) 2008 Eurotech S.p.A. <info@eurotech.it>
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License version 2 as published by
   9  * the Free Software Foundation
  10  */
  11
  12 #include <linux/errno.h>
  13 #include <linux/init.h>
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/delay.h>
  17 #include <linux/io.h>
  18 #include <linux/c2port.h>
  19
  20 #define DATA_PORT       0x325
  21 #define DIR_PORT        0x326
  22 #define    C2D             (1 << 0)
  23 #define    C2CK            (1 << 1)
  24
  25 static DEFINE_MUTEX(update_lock);
  26
  27 /*
  28  * C2 port operations
  29  */
  30
  31 static void duramar2150_c2port_access(struct c2port_device *dev, int status)
  32 {
  33         u8 v;
  34
  35         mutex_lock(&update_lock);
  36
  37         v = inb(DIR_PORT);
  38
  39         /* 0 = input, 1 = output */
  40         if (status)
  41                 outb(v | (C2D | C2CK), DIR_PORT);
  42         else
  43                 /* When access is "off" is important that both lines are set
  44                  * as inputs or hi-impedance */
  45                 outb(v & ~(C2D | C2CK), DIR_PORT);
  46
  47         mutex_unlock(&update_lock);
  48 }
  49
  50 static void duramar2150_c2port_c2d_dir(struct c2port_device *dev, int dir)
  51 {
  52         u8 v;
  53
  54         mutex_lock(&update_lock);
  55
  56         v = inb(DIR_PORT);
  57
  58         if (dir)
  59                 outb(v & ~C2D, DIR_PORT);
  60         else
  61                 outb(v | C2D, DIR_PORT);
  62
  63         mutex_unlock(&update_lock);
  64 }
  65
  66 static int duramar2150_c2port_c2d_get(struct c2port_device *dev)
  67 {
  68         return inb(DATA_PORT) & C2D;
  69 }
  70
  71 static void duramar2150_c2port_c2d_set(struct c2port_device *dev, int status)
  72 {
  73         u8 v;
  74
  75         mutex_lock(&update_lock);
  76
  77         v = inb(DATA_PORT);
  78
  79         if (status)
  80                 outb(v | C2D, DATA_PORT);
  81         else
  82                 outb(v & ~C2D, DATA_PORT);
  83
  84         mutex_unlock(&update_lock);
  85 }
  86
  87 static void duramar2150_c2port_c2ck_set(struct c2port_device *dev, int status)
  88 {
  89         u8 v;
  90
  91         mutex_lock(&update_lock);
  92
  93         v = inb(DATA_PORT);
  94
  95         if (status)
  96                 outb(v | C2CK, DATA_PORT);
  97         else
  98                 outb(v & ~C2CK, DATA_PORT);
  99
 100         mutex_unlock(&update_lock);
 101 }
 102
 103 static struct c2port_ops duramar2150_c2port_ops = {
 104         .block_size     = 512,  /* bytes */
 105         .blocks_num     = 30,   /* total flash size: 15360 bytes */
 106
 107         .access         = duramar2150_c2port_access,
 108         .c2d_dir        = duramar2150_c2port_c2d_dir,
 109         .c2d_get        = duramar2150_c2port_c2d_get,
 110         .c2d_set        = duramar2150_c2port_c2d_set,
 111         .c2ck_set       = duramar2150_c2port_c2ck_set,
 112 };
 113
 114 static struct c2port_device *duramar2150_c2port_dev;
 115
 116 /*
 117  * Module stuff
 118  */
 119
 120 static int __init duramar2150_c2port_init(void)
 121 {
 122         struct resource *res;
 123         int ret = 0;
 124
 125         res = request_region(0x325, 2, "c2port");
 126         if (!res)
 127                 return -EBUSY;
 128
 129         duramar2150_c2port_dev = c2port_device_register("uc",
 130                                         &duramar2150_c2port_ops, NULL);
 131         if (!duramar2150_c2port_dev) {
 132                 ret = -ENODEV;
 133                 goto free_region;
 134         }
 135
 136         return 0;
 137
 138 free_region:
 139         release_region(0x325, 2);
 140         return ret;
 141 }
 142
 143 static void __exit duramar2150_c2port_exit(void)
 144 {
 145         /* Setup the GPIOs as input by default (access = 0) */
 146         duramar2150_c2port_access(duramar2150_c2port_dev, 0);
 147
 148         c2port_device_unregister(duramar2150_c2port_dev);
 149
 150         release_region(0x325, 2);
 151 }
 152
 153 module_init(duramar2150_c2port_init);
 154 module_exit(duramar2150_c2port_exit);
 155
 156 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 157 MODULE_DESCRIPTION("Silicon Labs C2 port Linux support for Duramar 2150");
 158 MODULE_LICENSE("GPL");