root/drivers/staging/comedi/drivers/addi_watchdog.c

DEFINITIONS

1. addi_watchdog_insn_config
2. addi_watchdog_insn_read
3. addi_watchdog_insn_write
4. addi_watchdog_reset
5. addi_watchdog_init
6. addi_watchdog_module_init
7. addi_watchdog_module_exit

   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 
  17 struct 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  */
  32 static 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 
  62 static 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 
  76 static 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 
  98 void addi_watchdog_reset(unsigned long iobase)
  99 {
 100         outl(0x0, iobase + ADDI_TCW_CTRL_REG);
 101         outl(0x0, iobase + ADDI_TCW_RELOAD_REG);
 102 }
 103 EXPORT_SYMBOL_GPL(addi_watchdog_reset);
 104 
 105 int 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 }
 125 EXPORT_SYMBOL_GPL(addi_watchdog_init);
 126 
 127 static int __init addi_watchdog_module_init(void)
 128 {
 129         return 0;
 130 }
 131 module_init(addi_watchdog_module_init);
 132 
 133 static void __exit addi_watchdog_module_exit(void)
 134 {
 135 }
 136 module_exit(addi_watchdog_module_exit);
 137 
 138 MODULE_DESCRIPTION("ADDI-DATA Watchdog subdevice");
 139 MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
 140 MODULE_LICENSE("GPL");