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