LXR linux/drivers/staging/comedi/drivers/addi

   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 <linux/module.h>
  22#include "../comedidev.h"
  23#include "addi_tcw.h"
  24#include "addi_watchdog.h"
  25
  26struct addi_watchdog_private {
  27        unsigned long iobase;
  28        unsigned int wdog_ctrl;
  29};
  30
  31/*
  32 * The watchdog subdevice is configured with two INSN_CONFIG instructions:
  33 *
  34 * Enable the watchdog and set the reload timeout:
  35 *      data[0] = INSN_CONFIG_ARM
  36 *      data[1] = timeout reload value
  37 *
  38 * Disable the watchdog:
  39 *      data[0] = INSN_CONFIG_DISARM
  40 */
  41static int addi_watchdog_insn_config(struct comedi_device *dev,
  42                                     struct comedi_subdevice *s,
  43                                     struct comedi_insn *insn,
  44                                     unsigned int *data)
  45{
  46        struct addi_watchdog_private *spriv = s->private;
  47        unsigned int reload;
  48
  49        switch (data[0]) {
  50        case INSN_CONFIG_ARM:
  51                spriv->wdog_ctrl = ADDI_TCW_CTRL_ENA;
  52                reload = data[1] & s->maxdata;
  53                outl(reload, spriv->iobase + ADDI_TCW_RELOAD_REG);
  54
  55                /* Time base is 20ms, let the user know the timeout */
  56                dev_info(dev->class_dev, "watchdog enabled, timeout:%dms\n",
  57                        20 * reload + 20);
  58                break;
  59        case INSN_CONFIG_DISARM:
  60                spriv->wdog_ctrl = 0;
  61                break;
  62        default:
  63                return -EINVAL;
  64        }
  65
  66        outl(spriv->wdog_ctrl, spriv->iobase + ADDI_TCW_CTRL_REG);
  67
  68        return insn->n;
  69}
  70
  71static int addi_watchdog_insn_read(struct comedi_device *dev,
  72                                   struct comedi_subdevice *s,
  73                                   struct comedi_insn *insn,
  74                                   unsigned int *data)
  75{
  76        struct addi_watchdog_private *spriv = s->private;
  77        int i;
  78
  79        for (i = 0; i < insn->n; i++)
  80                data[i] = inl(spriv->iobase + ADDI_TCW_STATUS_REG);
  81
  82        return insn->n;
  83}
  84
  85static int addi_watchdog_insn_write(struct comedi_device *dev,
  86                                    struct comedi_subdevice *s,
  87                                    struct comedi_insn *insn,
  88                                    unsigned int *data)
  89{
  90        struct addi_watchdog_private *spriv = s->private;
  91        int i;
  92
  93        if (spriv->wdog_ctrl == 0) {
  94                dev_warn(dev->class_dev, "watchdog is disabled\n");
  95                return -EINVAL;
  96        }
  97
  98        /* "ping" the watchdog */
  99        for (i = 0; i < insn->n; i++) {
 100                outl(spriv->wdog_ctrl | ADDI_TCW_CTRL_TRIG,
 101                     spriv->iobase + ADDI_TCW_CTRL_REG);
 102        }
 103
 104        return insn->n;
 105}
 106
 107void addi_watchdog_reset(unsigned long iobase)
 108{
 109        outl(0x0, iobase + ADDI_TCW_CTRL_REG);
 110        outl(0x0, iobase + ADDI_TCW_RELOAD_REG);
 111}
 112EXPORT_SYMBOL_GPL(addi_watchdog_reset);
 113
 114int addi_watchdog_init(struct comedi_subdevice *s, unsigned long iobase)
 115{
 116        struct addi_watchdog_private *spriv;
 117
 118        spriv = comedi_alloc_spriv(s, sizeof(*spriv));
 119        if (!spriv)
 120                return -ENOMEM;
 121
 122        spriv->iobase = iobase;
 123
 124        s->type         = COMEDI_SUBD_TIMER;
 125        s->subdev_flags = SDF_WRITABLE;
 126        s->n_chan       = 1;
 127        s->maxdata      = 0xff;
 128        s->insn_config  = addi_watchdog_insn_config;
 129        s->insn_read    = addi_watchdog_insn_read;
 130        s->insn_write   = addi_watchdog_insn_write;
 131
 132        return 0;
 133}
 134EXPORT_SYMBOL_GPL(addi_watchdog_init);
 135
 136static int __init addi_watchdog_module_init(void)
 137{
 138        return 0;
 139}
 140module_init(addi_watchdog_module_init);
 141
 142static void __exit addi_watchdog_module_exit(void)
 143{
 144}
 145module_exit(addi_watchdog_module_exit);
 146
 147MODULE_DESCRIPTION("ADDI-DATA Watchdog subdevice");
 148MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
 149MODULE_LICENSE("GPL");
 150