linux/drivers/watchdog/mena21_wdt.c
<<
>>
Prefs
   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Watchdog driver for the A21 VME CPU Boards
   4 *
   5 * Copyright (C) 2013 MEN Mikro Elektronik Nuernberg GmbH
   6 *
   7 */
   8#include <linux/module.h>
   9#include <linux/moduleparam.h>
  10#include <linux/types.h>
  11#include <linux/kernel.h>
  12#include <linux/slab.h>
  13#include <linux/platform_device.h>
  14#include <linux/watchdog.h>
  15#include <linux/uaccess.h>
  16#include <linux/gpio/consumer.h>
  17#include <linux/delay.h>
  18#include <linux/bitops.h>
  19#include <linux/of.h>
  20
  21#define NUM_GPIOS 6
  22
  23enum a21_wdt_gpios {
  24        GPIO_WD_ENAB,
  25        GPIO_WD_FAST,
  26        GPIO_WD_TRIG,
  27        GPIO_WD_RST0,
  28        GPIO_WD_RST1,
  29        GPIO_WD_RST2,
  30};
  31
  32struct a21_wdt_drv {
  33        struct watchdog_device wdt;
  34        struct gpio_desc *gpios[NUM_GPIOS];
  35};
  36
  37static bool nowayout = WATCHDOG_NOWAYOUT;
  38module_param(nowayout, bool, 0);
  39MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  40                            __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  41
  42static unsigned int a21_wdt_get_bootstatus(struct a21_wdt_drv *drv)
  43{
  44        int reset = 0;
  45
  46        reset |= gpiod_get_value(drv->gpios[GPIO_WD_RST0]) ? (1 << 0) : 0;
  47        reset |= gpiod_get_value(drv->gpios[GPIO_WD_RST1]) ? (1 << 1) : 0;
  48        reset |= gpiod_get_value(drv->gpios[GPIO_WD_RST2]) ? (1 << 2) : 0;
  49
  50        return reset;
  51}
  52
  53static int a21_wdt_start(struct watchdog_device *wdt)
  54{
  55        struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
  56
  57        gpiod_set_value(drv->gpios[GPIO_WD_ENAB], 1);
  58
  59        return 0;
  60}
  61
  62static int a21_wdt_stop(struct watchdog_device *wdt)
  63{
  64        struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
  65
  66        gpiod_set_value(drv->gpios[GPIO_WD_ENAB], 0);
  67
  68        return 0;
  69}
  70
  71static int a21_wdt_ping(struct watchdog_device *wdt)
  72{
  73        struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
  74
  75        gpiod_set_value(drv->gpios[GPIO_WD_TRIG], 0);
  76        ndelay(10);
  77        gpiod_set_value(drv->gpios[GPIO_WD_TRIG], 1);
  78
  79        return 0;
  80}
  81
  82static int a21_wdt_set_timeout(struct watchdog_device *wdt,
  83                               unsigned int timeout)
  84{
  85        struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
  86
  87        if (timeout != 1 && timeout != 30) {
  88                dev_err(wdt->parent, "Only 1 and 30 allowed as timeout\n");
  89                return -EINVAL;
  90        }
  91
  92        if (timeout == 30 && wdt->timeout == 1) {
  93                dev_err(wdt->parent,
  94                        "Transition from fast to slow mode not allowed\n");
  95                return -EINVAL;
  96        }
  97
  98        if (timeout == 1)
  99                gpiod_set_value(drv->gpios[GPIO_WD_FAST], 1);
 100        else
 101                gpiod_set_value(drv->gpios[GPIO_WD_FAST], 0);
 102
 103        wdt->timeout = timeout;
 104
 105        return 0;
 106}
 107
 108static const struct watchdog_info a21_wdt_info = {
 109        .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 110        .identity = "MEN A21 Watchdog",
 111};
 112
 113static const struct watchdog_ops a21_wdt_ops = {
 114        .owner = THIS_MODULE,
 115        .start = a21_wdt_start,
 116        .stop = a21_wdt_stop,
 117        .ping = a21_wdt_ping,
 118        .set_timeout = a21_wdt_set_timeout,
 119};
 120
 121static struct watchdog_device a21_wdt = {
 122        .info = &a21_wdt_info,
 123        .ops = &a21_wdt_ops,
 124        .min_timeout = 1,
 125        .max_timeout = 30,
 126};
 127
 128static int a21_wdt_probe(struct platform_device *pdev)
 129{
 130        struct device *dev = &pdev->dev;
 131        struct a21_wdt_drv *drv;
 132        unsigned int reset = 0;
 133        int num_gpios;
 134        int ret;
 135        int i;
 136
 137        drv = devm_kzalloc(dev, sizeof(struct a21_wdt_drv), GFP_KERNEL);
 138        if (!drv)
 139                return -ENOMEM;
 140
 141        num_gpios = gpiod_count(dev, NULL);
 142        if (num_gpios != NUM_GPIOS) {
 143                dev_err(dev, "gpios DT property wrong, got %d want %d",
 144                        num_gpios, NUM_GPIOS);
 145                return -ENODEV;
 146        }
 147
 148        /* Request the used GPIOs */
 149        for (i = 0; i < num_gpios; i++) {
 150                enum gpiod_flags gflags;
 151
 152                if (i < GPIO_WD_RST0)
 153                        gflags = GPIOD_ASIS;
 154                else
 155                        gflags = GPIOD_IN;
 156                drv->gpios[i] = devm_gpiod_get_index(dev, NULL, i, gflags);
 157                if (IS_ERR(drv->gpios[i]))
 158                        return PTR_ERR(drv->gpios[i]);
 159
 160                gpiod_set_consumer_name(drv->gpios[i], "MEN A21 Watchdog");
 161
 162                /*
 163                 * Retrieve the initial value from the GPIOs that should be
 164                 * output, then set up the line as output with that value.
 165                 */
 166                if (i < GPIO_WD_RST0) {
 167                        int val;
 168
 169                        val = gpiod_get_value(drv->gpios[i]);
 170                        gpiod_direction_output(drv->gpios[i], val);
 171                }
 172        }
 173
 174        watchdog_init_timeout(&a21_wdt, 30, dev);
 175        watchdog_set_nowayout(&a21_wdt, nowayout);
 176        watchdog_set_drvdata(&a21_wdt, drv);
 177        a21_wdt.parent = dev;
 178
 179        reset = a21_wdt_get_bootstatus(drv);
 180        if (reset == 2)
 181                a21_wdt.bootstatus |= WDIOF_EXTERN1;
 182        else if (reset == 4)
 183                a21_wdt.bootstatus |= WDIOF_CARDRESET;
 184        else if (reset == 5)
 185                a21_wdt.bootstatus |= WDIOF_POWERUNDER;
 186        else if (reset == 7)
 187                a21_wdt.bootstatus |= WDIOF_EXTERN2;
 188
 189        drv->wdt = a21_wdt;
 190        dev_set_drvdata(dev, drv);
 191
 192        ret = devm_watchdog_register_device(dev, &a21_wdt);
 193        if (ret)
 194                return ret;
 195
 196        dev_info(dev, "MEN A21 watchdog timer driver enabled\n");
 197
 198        return 0;
 199}
 200
 201static void a21_wdt_shutdown(struct platform_device *pdev)
 202{
 203        struct a21_wdt_drv *drv = dev_get_drvdata(&pdev->dev);
 204
 205        gpiod_set_value(drv->gpios[GPIO_WD_ENAB], 0);
 206}
 207
 208static const struct of_device_id a21_wdt_ids[] = {
 209        { .compatible = "men,a021-wdt" },
 210        { },
 211};
 212MODULE_DEVICE_TABLE(of, a21_wdt_ids);
 213
 214static struct platform_driver a21_wdt_driver = {
 215        .probe = a21_wdt_probe,
 216        .shutdown = a21_wdt_shutdown,
 217        .driver = {
 218                .name = "a21-watchdog",
 219                .of_match_table = a21_wdt_ids,
 220        },
 221};
 222
 223module_platform_driver(a21_wdt_driver);
 224
 225MODULE_AUTHOR("MEN Mikro Elektronik");
 226MODULE_DESCRIPTION("MEN A21 Watchdog");
 227MODULE_LICENSE("GPL");
 228MODULE_ALIAS("platform:a21-watchdog");
 229