drivers/misc/c2port/c2port-duramar2150.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  Silicon Labs C2 port Linux support for Eurotech Duramar 2150
   4  *
   5  *  Copyright (c) 2008 Rodolfo Giometti <giometti@linux.it>
   6  *  Copyright (c) 2008 Eurotech S.p.A. <info@eurotech.it>
   7  */
   8
   9 #include <linux/errno.h>
  10 #include <linux/init.h>
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/delay.h>
  14 #include <linux/io.h>
  15 #include <linux/ioport.h>
  16 #include <linux/c2port.h>
  17
  18 #define DATA_PORT       0x325
  19 #define DIR_PORT        0x326
  20 #define    C2D             (1 << 0)
  21 #define    C2CK            (1 << 1)
  22
  23 static DEFINE_MUTEX(update_lock);
  24
  25 /*
  26  * C2 port operations
  27  */
  28
  29 static void duramar2150_c2port_access(struct c2port_device *dev, int status)
  30 {
  31         u8 v;
  32
  33         mutex_lock(&update_lock);
  34
  35         v = inb(DIR_PORT);
  36
  37         /* 0 = input, 1 = output */
  38         if (status)
  39                 outb(v | (C2D | C2CK), DIR_PORT);
  40         else
  41                 /* When access is "off" is important that both lines are set
  42                  * as inputs or hi-impedance */
  43                 outb(v & ~(C2D | C2CK), DIR_PORT);
  44
  45         mutex_unlock(&update_lock);
  46 }
  47
  48 static void duramar2150_c2port_c2d_dir(struct c2port_device *dev, int dir)
  49 {
  50         u8 v;
  51
  52         mutex_lock(&update_lock);
  53
  54         v = inb(DIR_PORT);
  55
  56         if (dir)
  57                 outb(v & ~C2D, DIR_PORT);
  58         else
  59                 outb(v | C2D, DIR_PORT);
  60
  61         mutex_unlock(&update_lock);
  62 }
  63
  64 static int duramar2150_c2port_c2d_get(struct c2port_device *dev)
  65 {
  66         return inb(DATA_PORT) & C2D;
  67 }
  68
  69 static void duramar2150_c2port_c2d_set(struct c2port_device *dev, int status)
  70 {
  71         u8 v;
  72
  73         mutex_lock(&update_lock);
  74
  75         v = inb(DATA_PORT);
  76
  77         if (status)
  78                 outb(v | C2D, DATA_PORT);
  79         else
  80                 outb(v & ~C2D, DATA_PORT);
  81
  82         mutex_unlock(&update_lock);
  83 }
  84
  85 static void duramar2150_c2port_c2ck_set(struct c2port_device *dev, int status)
  86 {
  87         u8 v;
  88
  89         mutex_lock(&update_lock);
  90
  91         v = inb(DATA_PORT);
  92
  93         if (status)
  94                 outb(v | C2CK, DATA_PORT);
  95         else
  96                 outb(v & ~C2CK, DATA_PORT);
  97
  98         mutex_unlock(&update_lock);
  99 }
 100
 101 static struct c2port_ops duramar2150_c2port_ops = {
 102         .block_size     = 512,  /* bytes */
 103         .blocks_num     = 30,   /* total flash size: 15360 bytes */
 104
 105         .access         = duramar2150_c2port_access,
 106         .c2d_dir        = duramar2150_c2port_c2d_dir,
 107         .c2d_get        = duramar2150_c2port_c2d_get,
 108         .c2d_set        = duramar2150_c2port_c2d_set,
 109         .c2ck_set       = duramar2150_c2port_c2ck_set,
 110 };
 111
 112 static struct c2port_device *duramar2150_c2port_dev;
 113
 114 /*
 115  * Module stuff
 116  */
 117
 118 static int __init duramar2150_c2port_init(void)
 119 {
 120         struct resource *res;
 121         int ret = 0;
 122
 123         res = request_region(0x325, 2, "c2port");
 124         if (!res)
 125                 return -EBUSY;
 126
 127         duramar2150_c2port_dev = c2port_device_register("uc",
 128                                         &duramar2150_c2port_ops, NULL);
 129         if (IS_ERR(duramar2150_c2port_dev)) {
 130                 ret = PTR_ERR(duramar2150_c2port_dev);
 131                 goto free_region;
 132         }
 133
 134         return 0;
 135
 136 free_region:
 137         release_region(0x325, 2);
 138         return ret;
 139 }
 140
 141 static void __exit duramar2150_c2port_exit(void)
 142 {
 143         /* Setup the GPIOs as input by default (access = 0) */
 144         duramar2150_c2port_access(duramar2150_c2port_dev, 0);
 145
 146         c2port_device_unregister(duramar2150_c2port_dev);
 147
 148         release_region(0x325, 2);
 149 }
 150
 151 module_init(duramar2150_c2port_init);
 152 module_exit(duramar2150_c2port_exit);
 153
 154 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 155 MODULE_DESCRIPTION("Silicon Labs C2 port Linux support for Duramar 2150");
 156 MODULE_LICENSE("GPL");