addi_watchdog.c revision 588ba6dc5fb4bdca47a3da38c2718fbb82d3eee1 
1/*
2 * COMEDI driver for the watchdog subdevice found on some addi-data boards
3 * Copyright (c) 2013 H Hartley Sweeten <hsweeten@visionengravers.com>
4 *
5 * Based on implementations in various addi-data COMEDI drivers.
6 *
7 * COMEDI - Linux Control and Measurement Device Interface
8 * Copyright (C) 1998 David A. Schleef <ds@schleef.org>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18 * GNU General Public License for more details.
19 */
20
21#include "../comedidev.h"
22#include "addi_watchdog.h"
23
24/*
25 * Register offsets/defines for the addi-data watchdog
26 */
27#define ADDI_WDOG_REG			0x00
28#define ADDI_WDOG_RELOAD_REG		0x04
29#define ADDI_WDOG_TIMEBASE		0x08
30#define ADDI_WDOG_CTRL_REG		0x0c
31#define ADDI_WDOG_CTRL_ENABLE		(1 << 0)
32#define ADDI_WDOG_CTRL_SW_TRIG		(1 << 9)
33#define ADDI_WDOG_STATUS_REG		0x10
34#define ADDI_WDOG_STATUS_ENABLED	(1 << 0)
35#define ADDI_WDOG_STATUS_SW_TRIG	(1 << 1)
36
37struct addi_watchdog_private {
38	unsigned long iobase;
39	unsigned int wdog_ctrl;
40};
41
42/*
43 * The watchdog subdevice is configured with two INSN_CONFIG instructions:
44 *
45 * Enable the watchdog and set the reload timeout:
46 *	data[0] = INSN_CONFIG_ARM
47 *	data[1] = timeout reload value
48 *
49 * Disable the watchdog:
50 *	data[0] = INSN_CONFIG_DISARM
51 */
52static int addi_watchdog_insn_config(struct comedi_device *dev,
53				     struct comedi_subdevice *s,
54				     struct comedi_insn *insn,
55				     unsigned int *data)
56{
57	struct addi_watchdog_private *spriv = s->private;
58	unsigned int reload;
59
60	switch (data[0]) {
61	case INSN_CONFIG_ARM:
62		spriv->wdog_ctrl = ADDI_WDOG_CTRL_ENABLE;
63		reload = data[1] & s->maxdata;
64		outl(reload, spriv->iobase + ADDI_WDOG_RELOAD_REG);
65
66		/* Time base is 20ms, let the user know the timeout */
67		dev_info(dev->class_dev, "watchdog enabled, timeout:%dms\n",
68			20 * reload + 20);
69		break;
70	case INSN_CONFIG_DISARM:
71		spriv->wdog_ctrl = 0;
72		break;
73	default:
74		return -EINVAL;
75	}
76
77	outl(spriv->wdog_ctrl, spriv->iobase + ADDI_WDOG_CTRL_REG);
78
79	return insn->n;
80}
81
82static int addi_watchdog_insn_read(struct comedi_device *dev,
83				   struct comedi_subdevice *s,
84				   struct comedi_insn *insn,
85				   unsigned int *data)
86{
87	struct addi_watchdog_private *spriv = s->private;
88	int i;
89
90	for (i = 0; i < insn->n; i++)
91		data[i] = inl(spriv->iobase + ADDI_WDOG_STATUS_REG);
92
93	return insn->n;
94}
95
96static int addi_watchdog_insn_write(struct comedi_device *dev,
97				    struct comedi_subdevice *s,
98				    struct comedi_insn *insn,
99				    unsigned int *data)
100{
101	struct addi_watchdog_private *spriv = s->private;
102	int i;
103
104	if (spriv->wdog_ctrl == 0) {
105		dev_warn(dev->class_dev, "watchdog is disabled\n");
106		return -EINVAL;
107	}
108
109	/* "ping" the watchdog */
110	for (i = 0; i < insn->n; i++) {
111		outl(spriv->wdog_ctrl | ADDI_WDOG_CTRL_SW_TRIG,
112		     spriv->iobase + ADDI_WDOG_CTRL_REG);
113	}
114
115	return insn->n;
116}
117
118void addi_watchdog_reset(unsigned long iobase)
119{
120	outl(0x0, iobase + ADDI_WDOG_CTRL_REG);
121	outl(0x0, iobase + ADDI_WDOG_RELOAD_REG);
122}
123EXPORT_SYMBOL_GPL(addi_watchdog_reset);
124
125int addi_watchdog_init(struct comedi_subdevice *s, unsigned long iobase)
126{
127	struct addi_watchdog_private *spriv;
128
129	spriv = kzalloc(sizeof(*spriv), GFP_KERNEL);
130	if (!spriv)
131		return -ENOMEM;
132	comedi_set_spriv(s, spriv);
133
134	spriv->iobase = iobase;
135
136	s->type		= COMEDI_SUBD_TIMER;
137	s->subdev_flags	= SDF_WRITEABLE;
138	s->n_chan	= 1;
139	s->maxdata	= 0xff;
140	s->insn_config	= addi_watchdog_insn_config;
141	s->insn_read	= addi_watchdog_insn_read;
142	s->insn_write	= addi_watchdog_insn_write;
143
144	return 0;
145}
146EXPORT_SYMBOL_GPL(addi_watchdog_init);
147
148static int __init addi_watchdog_module_init(void)
149{
150	return 0;
151}
152module_init(addi_watchdog_module_init);
153
154static void __exit addi_watchdog_module_exit(void)
155{
156}
157module_exit(addi_watchdog_module_exit);
158
159MODULE_DESCRIPTION("ADDI-DATA Watchdog subdevice");
160MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
161MODULE_LICENSE("GPL");
162