arch/mips/basler/excite/excite_iodev.c

   1 /*
   2  *  Copyright (C) 2005 by Basler Vision Technologies AG
   3  *  Author: Thomas Koeller <thomas.koeller@baslerweb.com>
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19
  20 #include <linux/compiler.h>
  21 #include <linux/init.h>
  22 #include <linux/module.h>
  23 #include <linux/sched.h>
  24 #include <linux/wait.h>
  25 #include <linux/poll.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/platform_device.h>
  28 #include <linux/miscdevice.h>
  29
  30 #include "excite_iodev.h"
  31
  32
  33
  34 static const struct resource *iodev_get_resource(struct platform_device *, const char *, unsigned int);
  35 static int __init iodev_probe(struct device *);
  36 static int __exit iodev_remove(struct device *);
  37 static int iodev_open(struct inode *, struct file *);
  38 static int iodev_release(struct inode *, struct file *);
  39 static ssize_t iodev_read(struct file *, char __user *, size_t s, loff_t *);
  40 static unsigned int iodev_poll(struct file *, struct poll_table_struct *);
  41 static irqreturn_t iodev_irqhdl(int, void *);
  42
  43
  44
  45 static const char iodev_name[] = "iodev";
  46 static unsigned int iodev_irq;
  47 static DECLARE_WAIT_QUEUE_HEAD(wq);
  48
  49
  50
  51 static const struct file_operations fops =
  52 {
  53         .owner          = THIS_MODULE,
  54         .open           = iodev_open,
  55         .release        = iodev_release,
  56         .read           = iodev_read,
  57         .poll           = iodev_poll
  58 };
  59
  60 static struct miscdevice miscdev =
  61 {
  62         .minor          = MISC_DYNAMIC_MINOR,
  63         .name           = iodev_name,
  64         .fops           = &fops
  65 };
  66
  67 static struct device_driver iodev_driver =
  68 {
  69         .name           = (char *) iodev_name,
  70         .bus            = &platform_bus_type,
  71         .owner          = THIS_MODULE,
  72         .probe          = iodev_probe,
  73         .remove         = __exit_p(iodev_remove)
  74 };
  75
  76
  77
  78 static const struct resource *
  79 iodev_get_resource(struct platform_device *pdv, const char *name,
  80                      unsigned int type)
  81 {
  82         char buf[80];
  83         if (snprintf(buf, sizeof buf, "%s_0", name) >= sizeof buf)
  84                 return NULL;
  85         return platform_get_resource_byname(pdv, type, buf);
  86 }
  87
  88
  89
  90 /* No hotplugging on the platform bus - use __init */
  91 static int __init iodev_probe(struct device *dev)
  92 {
  93         struct platform_device * const pdv = to_platform_device(dev);
  94         const struct resource * const ri =
  95                 iodev_get_resource(pdv, IODEV_RESOURCE_IRQ, IORESOURCE_IRQ);
  96
  97         if (unlikely(!ri))
  98                 return -ENXIO;
  99
 100         iodev_irq = ri->start;
 101         return misc_register(&miscdev);
 102 }
 103
 104
 105
 106 static int __exit iodev_remove(struct device *dev)
 107 {
 108         return misc_deregister(&miscdev);
 109 }
 110
 111 static int iodev_open(struct inode *i, struct file *f)
 112 {
 113         return request_irq(iodev_irq, iodev_irqhdl, IRQF_DISABLED,
 114                            iodev_name, &miscdev);
 115 }
 116
 117 static int iodev_release(struct inode *i, struct file *f)
 118 {
 119         free_irq(iodev_irq, &miscdev);
 120         return 0;
 121 }
 122
 123
 124
 125
 126 static ssize_t
 127 iodev_read(struct file *f, char __user *d, size_t s, loff_t *o)
 128 {
 129         ssize_t ret;
 130         DEFINE_WAIT(w);
 131
 132         prepare_to_wait(&wq, &w, TASK_INTERRUPTIBLE);
 133         if (!signal_pending(current))
 134                 schedule();
 135         ret = signal_pending(current) ? -ERESTARTSYS : 0;
 136         finish_wait(&wq, &w);
 137         return ret;
 138 }
 139
 140
 141 static unsigned int iodev_poll(struct file *f, struct poll_table_struct *p)
 142 {
 143         poll_wait(f, &wq, p);
 144         return POLLOUT | POLLWRNORM;
 145 }
 146
 147 static irqreturn_t iodev_irqhdl(int irq, void *ctxt)
 148 {
 149         wake_up(&wq);
 150
 151         return IRQ_HANDLED;
 152 }
 153
 154 static int __init iodev_init_module(void)
 155 {
 156         return driver_register(&iodev_driver);
 157 }
 158
 159
 160
 161 static void __exit iodev_cleanup_module(void)
 162 {
 163         driver_unregister(&iodev_driver);
 164 }
 165
 166 module_init(iodev_init_module);
 167 module_exit(iodev_cleanup_module);
 168
 169
 170
 171 MODULE_AUTHOR("Thomas Koeller <thomas.koeller@baslerweb.com>");
 172 MODULE_DESCRIPTION("Basler eXcite i/o interrupt handler");
 173 MODULE_VERSION("0.0");
 174 MODULE_LICENSE("GPL");