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_watchdog.h"
  24
  25/*
  26 * Register offsets/defines for the addi-data watchdog
  27 */
  28#define ADDI_WDOG_REG                   0x00
  29#define ADDI_WDOG_RELOAD_REG            0x04
  30#define ADDI_WDOG_TIMEBASE              0x08
  31#define ADDI_WDOG_CTRL_REG              0x0c
  32#define ADDI_WDOG_CTRL_ENABLE           (1 << 0)
  33#define ADDI_WDOG_CTRL_SW_TRIG          (1 << 9)
  34#define ADDI_WDOG_STATUS_REG            0x10
  35#define ADDI_WDOG_STATUS_ENABLED        (1 << 0)
  36#define ADDI_WDOG_STATUS_SW_TRIG        (1 << 1)
  37
  38struct addi_watchdog_private {
  39        unsigned long iobase;
  40        unsigned int wdog_ctrl;
  41};
  42
  43/*
  44 * The watchdog subdevice is configured with two INSN_CONFIG instructions:
  45 *
  46 * Enable the watchdog and set the reload timeout:
  47 *      data[0] = INSN_CONFIG_ARM
  48 *      data[1] = timeout reload value
  49 *
  50 * Disable the watchdog:
  51 *      data[0] = INSN_CONFIG_DISARM
  52 */
  53static int addi_watchdog_insn_config(struct comedi_device *dev,
  54                                     struct comedi_subdevice *s,
  55                                     struct comedi_insn *insn,
  56                                     unsigned int *data)
  57{
  58        struct addi_watchdog_private *spriv = s->private;
  59        unsigned int reload;
  60
  61        switch (data[0]) {
  62        case INSN_CONFIG_ARM:
  63                spriv->wdog_ctrl = ADDI_WDOG_CTRL_ENABLE;
  64                reload = data[1] & s->maxdata;
  65                outl(reload, spriv->iobase + ADDI_WDOG_RELOAD_REG);
  66
  67                /* Time base is 20ms, let the user know the timeout */
  68                dev_info(dev->class_dev, "watchdog enabled, timeout:%dms\n",
  69                        20 * reload + 20);
  70                break;
  71        case INSN_CONFIG_DISARM:
  72                spriv->wdog_ctrl = 0;
  73                break;
  74        default:
  75                return -EINVAL;
  76        }
  77
  78        outl(spriv->wdog_ctrl, spriv->iobase + ADDI_WDOG_CTRL_REG);
  79
  80        return insn->n;
  81}
  82
  83static int addi_watchdog_insn_read(struct comedi_device *dev,
  84                                   struct comedi_subdevice *s,
  85                                   struct comedi_insn *insn,
  86                                   unsigned int *data)
  87{
  88        struct addi_watchdog_private *spriv = s->private;
  89        int i;
  90
  91        for (i = 0; i < insn->n; i++)
  92                data[i] = inl(spriv->iobase + ADDI_WDOG_STATUS_REG);
  93
  94        return insn->n;
  95}
  96
  97static int addi_watchdog_insn_write(struct comedi_device *dev,
  98                                    struct comedi_subdevice *s,
  99                                    struct comedi_insn *insn,
 100                                    unsigned int *data)
 101{
 102        struct addi_watchdog_private *spriv = s->private;
 103        int i;
 104
 105        if (spriv->wdog_ctrl == 0) {
 106                dev_warn(dev->class_dev, "watchdog is disabled\n");
 107                return -EINVAL;
 108        }
 109
 110        /* "ping" the watchdog */
 111        for (i = 0; i < insn->n; i++) {
 112                outl(spriv->wdog_ctrl | ADDI_WDOG_CTRL_SW_TRIG,
 113                     spriv->iobase + ADDI_WDOG_CTRL_REG);
 114        }
 115
 116        return insn->n;
 117}
 118
 119void addi_watchdog_reset(unsigned long iobase)
 120{
 121        outl(0x0, iobase + ADDI_WDOG_CTRL_REG);
 122        outl(0x0, iobase + ADDI_WDOG_RELOAD_REG);
 123}
 124EXPORT_SYMBOL_GPL(addi_watchdog_reset);
 125
 126int addi_watchdog_init(struct comedi_subdevice *s, unsigned long iobase)
 127{
 128        struct addi_watchdog_private *spriv;
 129
 130        spriv = comedi_alloc_spriv(s, sizeof(*spriv));
 131        if (!spriv)
 132                return -ENOMEM;
 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