pcmad.c

  1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * pcmad.c
  4 * Hardware driver for Winsystems PCM-A/D12 and PCM-A/D16
  5 *
  6 * COMEDI - Linux Control and Measurement Device Interface
  7 * Copyright (C) 2000,2001 David A. Schleef <ds@schleef.org>
  8 */
  9
 10/*
 11 * Driver: pcmad
 12 * Description: Winsystems PCM-A/D12, PCM-A/D16
 13 * Devices: [Winsystems] PCM-A/D12 (pcmad12), PCM-A/D16 (pcmad16)
 14 * Author: ds
 15 * Status: untested
 16 *
 17 * This driver was written on a bet that I couldn't write a driver
 18 * in less than 2 hours.  I won the bet, but never got paid.  =(
 19 *
 20 * Configuration options:
 21 *   [0] - I/O port base
 22 *   [1] - IRQ (unused)
 23 *   [2] - Analog input reference (must match jumpers)
 24 *	   0 = single-ended (16 channels)
 25 *	   1 = differential (8 channels)
 26 *   [3] - Analog input encoding (must match jumpers)
 27 *	   0 = straight binary (0-5V input range)
 28 *	   1 = two's complement (+-10V input range)
 29 */
 30
 31#include <linux/module.h>
 32#include <linux/comedi/comedidev.h>
 33
 34#define PCMAD_STATUS		0
 35#define PCMAD_LSB		1
 36#define PCMAD_MSB		2
 37#define PCMAD_CONVERT		1
 38
 39struct pcmad_board_struct {
 40	const char *name;
 41	unsigned int ai_maxdata;
 42};
 43
 44static const struct pcmad_board_struct pcmad_boards[] = {
 45	{
 46		.name		= "pcmad12",
 47		.ai_maxdata	= 0x0fff,
 48	}, {
 49		.name		= "pcmad16",
 50		.ai_maxdata	= 0xffff,
 51	},
 52};
 53
 54static int pcmad_ai_eoc(struct comedi_device *dev,
 55			struct comedi_subdevice *s,
 56			struct comedi_insn *insn,
 57			unsigned long context)
 58{
 59	unsigned int status;
 60
 61	status = inb(dev->iobase + PCMAD_STATUS);
 62	if ((status & 0x3) == 0x3)
 63		return 0;
 64	return -EBUSY;
 65}
 66
 67static int pcmad_ai_insn_read(struct comedi_device *dev,
 68			      struct comedi_subdevice *s,
 69			      struct comedi_insn *insn,
 70			      unsigned int *data)
 71{
 72	unsigned int chan = CR_CHAN(insn->chanspec);
 73	unsigned int range = CR_RANGE(insn->chanspec);
 74	unsigned int val;
 75	int ret;
 76	int i;
 77
 78	for (i = 0; i < insn->n; i++) {
 79		outb(chan, dev->iobase + PCMAD_CONVERT);
 80
 81		ret = comedi_timeout(dev, s, insn, pcmad_ai_eoc, 0);
 82		if (ret)
 83			return ret;
 84
 85		val = inb(dev->iobase + PCMAD_LSB) |
 86		      (inb(dev->iobase + PCMAD_MSB) << 8);
 87
 88		/* data is shifted on the pcmad12, fix it */
 89		if (s->maxdata == 0x0fff)
 90			val >>= 4;
 91
 92		if (comedi_range_is_bipolar(s, range)) {
 93			/* munge the two's complement value */
 94			val ^= ((s->maxdata + 1) >> 1);
 95		}
 96
 97		data[i] = val;
 98	}
 99
100	return insn->n;
101}
102
103static int pcmad_attach(struct comedi_device *dev, struct comedi_devconfig *it)
104{
105	const struct pcmad_board_struct *board = dev->board_ptr;
106	struct comedi_subdevice *s;
107	int ret;
108
109	ret = comedi_request_region(dev, it->options[0], 0x04);
110	if (ret)
111		return ret;
112
113	ret = comedi_alloc_subdevices(dev, 1);
114	if (ret)
115		return ret;
116
117	s = &dev->subdevices[0];
118	s->type		= COMEDI_SUBD_AI;
119	if (it->options[1]) {
120		/* 8 differential channels */
121		s->subdev_flags	= SDF_READABLE | AREF_DIFF;
122		s->n_chan	= 8;
123	} else {
124		/* 16 single-ended channels */
125		s->subdev_flags	= SDF_READABLE | AREF_GROUND;
126		s->n_chan	= 16;
127	}
128	s->len_chanlist	= 1;
129	s->maxdata	= board->ai_maxdata;
130	s->range_table	= it->options[2] ? &range_bipolar10 : &range_unipolar5;
131	s->insn_read	= pcmad_ai_insn_read;
132
133	return 0;
134}
135
136static struct comedi_driver pcmad_driver = {
137	.driver_name	= "pcmad",
138	.module		= THIS_MODULE,
139	.attach		= pcmad_attach,
140	.detach		= comedi_legacy_detach,
141	.board_name	= &pcmad_boards[0].name,
142	.num_names	= ARRAY_SIZE(pcmad_boards),
143	.offset		= sizeof(pcmad_boards[0]),
144};
145module_comedi_driver(pcmad_driver);
146
147MODULE_AUTHOR("Comedi https://www.comedi.org");
148MODULE_DESCRIPTION("Comedi low-level driver");
149MODULE_LICENSE("GPL");