text: // SPDX-License-Identifier: GPL-2.0+
  /*
   * comedi/drivers/amplc_pc236.c
   * Driver for Amplicon PC36AT DIO boards.
   *
   * Copyright (C) 2002 MEV Ltd. <http://www.mev.co.uk/>
   *
   * COMEDI - Linux Control and Measurement Device Interface
   * Copyright (C) 2000 David A. Schleef <ds@schleef.org>
   */
  /*
   * Driver: amplc_pc236
   * Description: Amplicon PC36AT
   * Author: Ian Abbott <abbotti@mev.co.uk>
   * Devices: [Amplicon] PC36AT (pc36at)
   * Updated: Fri, 25 Jul 2014 15:32:40 +0000
   * Status: works
   *
   * Configuration options - PC36AT:
   *   [0] - I/O port base address
   *   [1] - IRQ (optional)
   *
   * The PC36AT board has a single 8255 appearing as subdevice 0.
   *
   * Subdevice 1 pretends to be a digital input device, but it always returns
   * 0 when read. However, if you run a command with scan_begin_src=TRIG_EXT,
   * a rising edge on port C bit 3 acts as an external trigger, which can be
   * used to wake up tasks.  This is like the comedi_parport device, but the
   * only way to physically disable the interrupt on the PC36AT is to remove
   * the IRQ jumper.  If no interrupt is connected, then subdevice 1 is
   * unused.
   */
  
  #include <linux/module.h>
  
  #include "../comedidev.h"
  
  #include "amplc_pc236.h"
  
  static int pc236_attach(struct comedi_device *dev, struct comedi_devconfig *it)
  {
  	struct pc236_private *devpriv;
  	int ret;
  
  	devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));
  	if (!devpriv)
  		return -ENOMEM;
  
  	ret = comedi_request_region(dev, it->options[0], 0x4);
  	if (ret)
  		return ret;
  
  	return amplc_pc236_common_attach(dev, dev->iobase, it->options[1], 0);
  }
  
  static const struct pc236_board pc236_boards[] = {
  	{
  		.name = "pc36at",
  	},
  };
  
  static struct comedi_driver amplc_pc236_driver = {
  	.driver_name = "amplc_pc236",
  	.module = THIS_MODULE,
  	.attach = pc236_attach,
  	.detach = comedi_legacy_detach,
  	.board_name = &pc236_boards[0].name,
  	.offset = sizeof(struct pc236_board),
  	.num_names = ARRAY_SIZE(pc236_boards),
  };
  
  module_comedi_driver(amplc_pc236_driver);
  
  MODULE_AUTHOR("Comedi http://www.comedi.org");
  MODULE_DESCRIPTION("Comedi driver for Amplicon PC36AT DIO boards");
  MODULE_LICENSE("GPL");
  