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

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * COMEDI driver for the watchdog subdevice found on some addi-data boards
   4 * Copyright (c) 2013 H Hartley Sweeten <hsweeten@visionengravers.com>
   5 *
   6 * Based on implementations in various addi-data COMEDI drivers.
   7 *
   8 * COMEDI - Linux Control and Measurement Device Interface
   9 * Copyright (C) 1998 David A. Schleef <ds@schleef.org>
  10 */
  11
  12#include <linux/module.h>
  13#include "../comedidev.h"
  14#include "addi_tcw.h"
  15#include "addi_watchdog.h"
  16
  17struct addi_watchdog_private {
  18        unsigned long iobase;
  19        unsigned int wdog_ctrl;
  20};
  21
  22/*
  23 * The watchdog subdevice is configured with two INSN_CONFIG instructions:
  24 *
  25 * Enable the watchdog and set the reload timeout:
  26 *      data[0] = INSN_CONFIG_ARM
  27 *      data[1] = timeout reload value
  28 *
  29 * Disable the watchdog:
  30 *      data[0] = INSN_CONFIG_DISARM
  31 */
  32static int addi_watchdog_insn_config(struct comedi_device *dev,
  33                                     struct comedi_subdevice *s,
  34                                     struct comedi_insn *insn,
  35                                     unsigned int *data)
  36{
  37        struct addi_watchdog_private *spriv = s->private;
  38        unsigned int reload;
  39
  40        switch (data[0]) {
  41        case INSN_CONFIG_ARM:
  42                spriv->wdog_ctrl = ADDI_TCW_CTRL_ENA;
  43                reload = data[1] & s->maxdata;
  44                outl(reload, spriv->iobase + ADDI_TCW_RELOAD_REG);
  45
  46                /* Time base is 20ms, let the user know the timeout */
  47                dev_info(dev->class_dev, "watchdog enabled, timeout:%dms\n",
  48                         20 * reload + 20);
  49                break;
  50        case INSN_CONFIG_DISARM:
  51                spriv->wdog_ctrl = 0;
  52                break;
  53        default:
  54                return -EINVAL;
  55        }
  56
  57        outl(spriv->wdog_ctrl, spriv->iobase + ADDI_TCW_CTRL_REG);
  58
  59        return insn->n;
  60}
  61
  62static int addi_watchdog_insn_read(struct comedi_device *dev,
  63                                   struct comedi_subdevice *s,
  64                                   struct comedi_insn *insn,
  65                                   unsigned int *data)
  66{
  67        struct addi_watchdog_private *spriv = s->private;
  68        int i;
  69
  70        for (i = 0; i < insn->n; i++)
  71                data[i] = inl(spriv->iobase + ADDI_TCW_STATUS_REG);
  72
  73        return insn->n;
  74}
  75
  76static int addi_watchdog_insn_write(struct comedi_device *dev,
  77                                    struct comedi_subdevice *s,
  78                                    struct comedi_insn *insn,
  79                                    unsigned int *data)
  80{
  81        struct addi_watchdog_private *spriv = s->private;
  82        int i;
  83
  84        if (spriv->wdog_ctrl == 0) {
  85                dev_warn(dev->class_dev, "watchdog is disabled\n");
  86                return -EINVAL;
  87        }
  88
  89        /* "ping" the watchdog */
  90        for (i = 0; i < insn->n; i++) {
  91                outl(spriv->wdog_ctrl | ADDI_TCW_CTRL_TRIG,
  92                     spriv->iobase + ADDI_TCW_CTRL_REG);
  93        }
  94
  95        return insn->n;
  96}
  97
  98void addi_watchdog_reset(unsigned long iobase)
  99{
 100        outl(0x0, iobase + ADDI_TCW_CTRL_REG);
 101        outl(0x0, iobase + ADDI_TCW_RELOAD_REG);
 102}
 103EXPORT_SYMBOL_GPL(addi_watchdog_reset);
 104
 105int addi_watchdog_init(struct comedi_subdevice *s, unsigned long iobase)
 106{
 107        struct addi_watchdog_private *spriv;
 108
 109        spriv = comedi_alloc_spriv(s, sizeof(*spriv));
 110        if (!spriv)
 111                return -ENOMEM;
 112
 113        spriv->iobase = iobase;
 114
 115        s->type         = COMEDI_SUBD_TIMER;
 116        s->subdev_flags = SDF_WRITABLE;
 117        s->n_chan       = 1;
 118        s->maxdata      = 0xff;
 119        s->insn_config  = addi_watchdog_insn_config;
 120        s->insn_read    = addi_watchdog_insn_read;
 121        s->insn_write   = addi_watchdog_insn_write;
 122
 123        return 0;
 124}
 125EXPORT_SYMBOL_GPL(addi_watchdog_init);
 126
 127static int __init addi_watchdog_module_init(void)
 128{
 129        return 0;
 130}
 131module_init(addi_watchdog_module_init);
 132
 133static void __exit addi_watchdog_module_exit(void)
 134{
 135}
 136module_exit(addi_watchdog_module_exit);
 137
 138MODULE_DESCRIPTION("ADDI-DATA Watchdog subdevice");
 139MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
 140MODULE_LICENSE("GPL");
 141