LXR linux/drivers/watchdog/rn5t618

   1/*
   2 * Watchdog driver for Ricoh RN5T618 PMIC
   3 *
   4 * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License
   8 * version 2 as published by the Free Software Foundation.
   9 *
  10 * You should have received a copy of the GNU General Public License
  11 * along with this program. If not, see <http://www.gnu.org/licenses/>.
  12 */
  13
  14#include <linux/device.h>
  15#include <linux/mfd/rn5t618.h>
  16#include <linux/module.h>
  17#include <linux/platform_device.h>
  18#include <linux/watchdog.h>
  19
  20#define DRIVER_NAME "rn5t618-wdt"
  21
  22static bool nowayout = WATCHDOG_NOWAYOUT;
  23static unsigned int timeout;
  24
  25module_param(timeout, uint, 0);
  26MODULE_PARM_DESC(timeout, "Initial watchdog timeout in seconds");
  27
  28module_param(nowayout, bool, 0);
  29MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  30                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  31
  32struct rn5t618_wdt {
  33        struct watchdog_device wdt_dev;
  34        struct rn5t618 *rn5t618;
  35};
  36
  37/*
  38 * This array encodes the values of WDOGTIM field for the supported
  39 * watchdog expiration times. If the watchdog is not accessed before
  40 * the timer expiration, the PMU generates an interrupt and if the CPU
  41 * doesn't clear it within one second the system is restarted.
  42 */
  43static const struct {
  44        u8 reg_val;
  45        unsigned int time;
  46} rn5t618_wdt_map[] = {
  47        { 0, 1 },
  48        { 1, 8 },
  49        { 2, 32 },
  50        { 3, 128 },
  51};
  52
  53static int rn5t618_wdt_set_timeout(struct watchdog_device *wdt_dev,
  54                                   unsigned int t)
  55{
  56        struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
  57        int ret, i;
  58
  59        for (i = 0; i < ARRAY_SIZE(rn5t618_wdt_map); i++) {
  60                if (rn5t618_wdt_map[i].time + 1 >= t)
  61                        break;
  62        }
  63
  64        if (i == ARRAY_SIZE(rn5t618_wdt_map))
  65                return -EINVAL;
  66
  67        ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
  68                                 RN5T618_WATCHDOG_WDOGTIM_M,
  69                                 rn5t618_wdt_map[i].reg_val);
  70        if (!ret)
  71                wdt_dev->timeout = rn5t618_wdt_map[i].time;
  72
  73        return ret;
  74}
  75
  76static int rn5t618_wdt_start(struct watchdog_device *wdt_dev)
  77{
  78        struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
  79        int ret;
  80
  81        ret = rn5t618_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
  82        if (ret)
  83                return ret;
  84
  85        /* enable repower-on */
  86        ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_REPCNT,
  87                                 RN5T618_REPCNT_REPWRON,
  88                                 RN5T618_REPCNT_REPWRON);
  89        if (ret)
  90                return ret;
  91
  92        /* enable watchdog */
  93        ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
  94                                 RN5T618_WATCHDOG_WDOGEN,
  95                                 RN5T618_WATCHDOG_WDOGEN);
  96        if (ret)
  97                return ret;
  98
  99        /* enable watchdog interrupt */
 100        return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_PWRIREN,
 101                                  RN5T618_PWRIRQ_IR_WDOG,
 102                                  RN5T618_PWRIRQ_IR_WDOG);
 103}
 104
 105static int rn5t618_wdt_stop(struct watchdog_device *wdt_dev)
 106{
 107        struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
 108
 109        return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
 110                                  RN5T618_WATCHDOG_WDOGEN, 0);
 111}
 112
 113static int rn5t618_wdt_ping(struct watchdog_device *wdt_dev)
 114{
 115        struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
 116        unsigned int val;
 117        int ret;
 118
 119        /* The counter is restarted after a R/W access to watchdog register */
 120        ret = regmap_read(wdt->rn5t618->regmap, RN5T618_WATCHDOG, &val);
 121        if (ret)
 122                return ret;
 123
 124        ret = regmap_write(wdt->rn5t618->regmap, RN5T618_WATCHDOG, val);
 125        if (ret)
 126                return ret;
 127
 128        /* Clear pending watchdog interrupt */
 129        return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_PWRIRQ,
 130                                  RN5T618_PWRIRQ_IR_WDOG, 0);
 131}
 132
 133static struct watchdog_info rn5t618_wdt_info = {
 134        .options        = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
 135                          WDIOF_KEEPALIVEPING,
 136        .identity       = DRIVER_NAME,
 137};
 138
 139static struct watchdog_ops rn5t618_wdt_ops = {
 140        .owner          = THIS_MODULE,
 141        .start          = rn5t618_wdt_start,
 142        .stop           = rn5t618_wdt_stop,
 143        .ping           = rn5t618_wdt_ping,
 144        .set_timeout    = rn5t618_wdt_set_timeout,
 145};
 146
 147static int rn5t618_wdt_probe(struct platform_device *pdev)
 148{
 149        struct rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent);
 150        struct rn5t618_wdt *wdt;
 151        int min_timeout, max_timeout;
 152
 153        wdt = devm_kzalloc(&pdev->dev, sizeof(struct rn5t618_wdt), GFP_KERNEL);
 154        if (!wdt)
 155                return -ENOMEM;
 156
 157        min_timeout = rn5t618_wdt_map[0].time;
 158        max_timeout = rn5t618_wdt_map[ARRAY_SIZE(rn5t618_wdt_map) - 1].time;
 159
 160        wdt->rn5t618 = rn5t618;
 161        wdt->wdt_dev.info = &rn5t618_wdt_info;
 162        wdt->wdt_dev.ops = &rn5t618_wdt_ops;
 163        wdt->wdt_dev.min_timeout = min_timeout;
 164        wdt->wdt_dev.max_timeout = max_timeout;
 165        wdt->wdt_dev.timeout = max_timeout;
 166        wdt->wdt_dev.parent = &pdev->dev;
 167
 168        watchdog_set_drvdata(&wdt->wdt_dev, wdt);
 169        watchdog_init_timeout(&wdt->wdt_dev, timeout, &pdev->dev);
 170        watchdog_set_nowayout(&wdt->wdt_dev, nowayout);
 171
 172        platform_set_drvdata(pdev, wdt);
 173
 174        return watchdog_register_device(&wdt->wdt_dev);
 175}
 176
 177static int rn5t618_wdt_remove(struct platform_device *pdev)
 178{
 179        struct rn5t618_wdt *wdt = platform_get_drvdata(pdev);
 180
 181        watchdog_unregister_device(&wdt->wdt_dev);
 182
 183        return 0;
 184}
 185
 186static struct platform_driver rn5t618_wdt_driver = {
 187        .probe = rn5t618_wdt_probe,
 188        .remove = rn5t618_wdt_remove,
 189        .driver = {
 190                .name   = DRIVER_NAME,
 191        },
 192};
 193
 194module_platform_driver(rn5t618_wdt_driver);
 195
 196MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
 197MODULE_DESCRIPTION("RN5T618 watchdog driver");
 198MODULE_LICENSE("GPL v2");
 199