drivers/staging/comedi/drivers/comedi_fc.c

   1 /*
   2     comedi/drivers/comedi_fc.c
   3
   4     This is a place for code driver writers wish to share between
   5     two or more drivers.  fc is short
   6     for frank-common.
   7
   8     Author:  Frank Mori Hess <fmhess@users.sourceforge.net>
   9     Copyright (C) 2002 Frank Mori Hess
  10
  11     This program is free software; you can redistribute it and/or modify
  12     it under the terms of the GNU General Public License as published by
  13     the Free Software Foundation; either version 2 of the License, or
  14     (at your option) any later version.
  15
  16     This program is distributed in the hope that it will be useful,
  17     but WITHOUT ANY WARRANTY; without even the implied warranty of
  18     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19     GNU General Public License for more details.
  20 */
  21
  22 #include "../comedidev.h"
  23
  24 #include "comedi_fc.h"
  25
  26 static void increment_scan_progress(struct comedi_subdevice *subd,
  27                                     unsigned int num_bytes)
  28 {
  29         struct comedi_async *async = subd->async;
  30         unsigned int scan_length = cfc_bytes_per_scan(subd);
  31
  32         async->scan_progress += num_bytes;
  33         if (async->scan_progress >= scan_length) {
  34                 async->scan_progress %= scan_length;
  35                 async->events |= COMEDI_CB_EOS;
  36         }
  37 }
  38
  39 /* Writes an array of data points to comedi's buffer */
  40 unsigned int cfc_write_array_to_buffer(struct comedi_subdevice *subd,
  41                                        void *data, unsigned int num_bytes)
  42 {
  43         struct comedi_async *async = subd->async;
  44         unsigned int retval;
  45
  46         if (num_bytes == 0)
  47                 return 0;
  48
  49         retval = comedi_buf_write_alloc(async, num_bytes);
  50         if (retval != num_bytes) {
  51                 dev_warn(subd->device->class_dev, "comedi: buffer overrun\n");
  52                 async->events |= COMEDI_CB_OVERFLOW;
  53                 return 0;
  54         }
  55
  56         comedi_buf_memcpy_to(async, 0, data, num_bytes);
  57         comedi_buf_write_free(async, num_bytes);
  58         increment_scan_progress(subd, num_bytes);
  59         async->events |= COMEDI_CB_BLOCK;
  60
  61         return num_bytes;
  62 }
  63 EXPORT_SYMBOL_GPL(cfc_write_array_to_buffer);
  64
  65 unsigned int cfc_read_array_from_buffer(struct comedi_subdevice *subd,
  66                                         void *data, unsigned int num_bytes)
  67 {
  68         struct comedi_async *async = subd->async;
  69
  70         if (num_bytes == 0)
  71                 return 0;
  72
  73         num_bytes = comedi_buf_read_alloc(async, num_bytes);
  74         comedi_buf_memcpy_from(async, 0, data, num_bytes);
  75         comedi_buf_read_free(async, num_bytes);
  76         increment_scan_progress(subd, num_bytes);
  77         async->events |= COMEDI_CB_BLOCK;
  78
  79         return num_bytes;
  80 }
  81 EXPORT_SYMBOL_GPL(cfc_read_array_from_buffer);
  82
  83 unsigned int cfc_handle_events(struct comedi_device *dev,
  84                                struct comedi_subdevice *subd)
  85 {
  86         unsigned int events = subd->async->events;
  87
  88         if (events == 0)
  89                 return events;
  90
  91         if (events & (COMEDI_CB_EOA | COMEDI_CB_ERROR | COMEDI_CB_OVERFLOW))
  92                 subd->cancel(dev, subd);
  93
  94         comedi_event(dev, subd);
  95
  96         return events;
  97 }
  98 EXPORT_SYMBOL_GPL(cfc_handle_events);
  99
 100 MODULE_AUTHOR("Frank Mori Hess <fmhess@users.sourceforge.net>");
 101 MODULE_DESCRIPTION("Shared functions for Comedi low-level drivers");
 102 MODULE_LICENSE("GPL");
 103
 104 static int __init comedi_fc_init_module(void)
 105 {
 106         return 0;
 107 }
 108
 109 static void __exit comedi_fc_cleanup_module(void)
 110 {
 111 }
 112
 113 module_init(comedi_fc_init_module);
 114 module_exit(comedi_fc_cleanup_module);