drivers/watchdog/ftwdt010_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Watchdog driver for Faraday Technology FTWDT010
   4  *
   5  * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
   6  *
   7  * Inspired by the out-of-tree drivers from OpenWRT:
   8  * Copyright (C) 2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
   9  */
  10
  11 #include <linux/bitops.h>
  12 #include <linux/init.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/io.h>
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/mod_devicetable.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/slab.h>
  20 #include <linux/watchdog.h>
  21
  22 #define FTWDT010_WDCOUNTER      0x0
  23 #define FTWDT010_WDLOAD         0x4
  24 #define FTWDT010_WDRESTART      0x8
  25 #define FTWDT010_WDCR           0xC
  26
  27 #define WDRESTART_MAGIC         0x5AB9
  28
  29 #define WDCR_CLOCK_5MHZ         BIT(4)
  30 #define WDCR_WDEXT              BIT(3)
  31 #define WDCR_WDINTR             BIT(2)
  32 #define WDCR_SYS_RST            BIT(1)
  33 #define WDCR_ENABLE             BIT(0)
  34
  35 #define WDT_CLOCK               5000000         /* 5 MHz */
  36
  37 struct ftwdt010_wdt {
  38         struct watchdog_device  wdd;
  39         struct device           *dev;
  40         void __iomem            *base;
  41         bool                    has_irq;
  42 };
  43
  44 static inline
  45 struct ftwdt010_wdt *to_ftwdt010_wdt(struct watchdog_device *wdd)
  46 {
  47         return container_of(wdd, struct ftwdt010_wdt, wdd);
  48 }
  49
  50 static void ftwdt010_enable(struct ftwdt010_wdt *gwdt,
  51                             unsigned int timeout,
  52                             bool need_irq)
  53 {
  54         u32 enable;
  55
  56         writel(timeout * WDT_CLOCK, gwdt->base + FTWDT010_WDLOAD);
  57         writel(WDRESTART_MAGIC, gwdt->base + FTWDT010_WDRESTART);
  58         /* set clock before enabling */
  59         enable = WDCR_CLOCK_5MHZ | WDCR_SYS_RST;
  60         writel(enable, gwdt->base + FTWDT010_WDCR);
  61         if (need_irq)
  62                 enable |= WDCR_WDINTR;
  63         enable |= WDCR_ENABLE;
  64         writel(enable, gwdt->base + FTWDT010_WDCR);
  65 }
  66
  67 static int ftwdt010_wdt_start(struct watchdog_device *wdd)
  68 {
  69         struct ftwdt010_wdt *gwdt = to_ftwdt010_wdt(wdd);
  70
  71         ftwdt010_enable(gwdt, wdd->timeout, gwdt->has_irq);
  72         return 0;
  73 }
  74
  75 static int ftwdt010_wdt_stop(struct watchdog_device *wdd)
  76 {
  77         struct ftwdt010_wdt *gwdt = to_ftwdt010_wdt(wdd);
  78
  79         writel(0, gwdt->base + FTWDT010_WDCR);
  80
  81         return 0;
  82 }
  83
  84 static int ftwdt010_wdt_ping(struct watchdog_device *wdd)
  85 {
  86         struct ftwdt010_wdt *gwdt = to_ftwdt010_wdt(wdd);
  87
  88         writel(WDRESTART_MAGIC, gwdt->base + FTWDT010_WDRESTART);
  89
  90         return 0;
  91 }
  92
  93 static int ftwdt010_wdt_set_timeout(struct watchdog_device *wdd,
  94                                   unsigned int timeout)
  95 {
  96         wdd->timeout = timeout;
  97         if (watchdog_active(wdd))
  98                 ftwdt010_wdt_start(wdd);
  99
 100         return 0;
 101 }
 102
 103 static int ftwdt010_wdt_restart(struct watchdog_device *wdd,
 104                                 unsigned long action, void *data)
 105 {
 106         ftwdt010_enable(to_ftwdt010_wdt(wdd), 0, false);
 107         return 0;
 108 }
 109
 110 static irqreturn_t ftwdt010_wdt_interrupt(int irq, void *data)
 111 {
 112         struct ftwdt010_wdt *gwdt = data;
 113
 114         watchdog_notify_pretimeout(&gwdt->wdd);
 115
 116         return IRQ_HANDLED;
 117 }
 118
 119 static const struct watchdog_ops ftwdt010_wdt_ops = {
 120         .start          = ftwdt010_wdt_start,
 121         .stop           = ftwdt010_wdt_stop,
 122         .ping           = ftwdt010_wdt_ping,
 123         .set_timeout    = ftwdt010_wdt_set_timeout,
 124         .restart        = ftwdt010_wdt_restart,
 125         .owner          = THIS_MODULE,
 126 };
 127
 128 static const struct watchdog_info ftwdt010_wdt_info = {
 129         .options        = WDIOF_KEEPALIVEPING
 130                         | WDIOF_MAGICCLOSE
 131                         | WDIOF_SETTIMEOUT,
 132         .identity       = KBUILD_MODNAME,
 133 };
 134
 135
 136 static int ftwdt010_wdt_probe(struct platform_device *pdev)
 137 {
 138         struct device *dev = &pdev->dev;
 139         struct ftwdt010_wdt *gwdt;
 140         unsigned int reg;
 141         int irq;
 142         int ret;
 143
 144         gwdt = devm_kzalloc(dev, sizeof(*gwdt), GFP_KERNEL);
 145         if (!gwdt)
 146                 return -ENOMEM;
 147
 148         gwdt->base = devm_platform_ioremap_resource(pdev, 0);
 149         if (IS_ERR(gwdt->base))
 150                 return PTR_ERR(gwdt->base);
 151
 152         gwdt->dev = dev;
 153         gwdt->wdd.info = &ftwdt010_wdt_info;
 154         gwdt->wdd.ops = &ftwdt010_wdt_ops;
 155         gwdt->wdd.min_timeout = 1;
 156         gwdt->wdd.max_timeout = 0xFFFFFFFF / WDT_CLOCK;
 157         gwdt->wdd.parent = dev;
 158
 159         /*
 160          * If 'timeout-sec' unspecified in devicetree, assume a 13 second
 161          * default.
 162          */
 163         gwdt->wdd.timeout = 13U;
 164         watchdog_init_timeout(&gwdt->wdd, 0, dev);
 165
 166         reg = readw(gwdt->base + FTWDT010_WDCR);
 167         if (reg & WDCR_ENABLE) {
 168                 /* Watchdog was enabled by the bootloader, disable it. */
 169                 reg &= ~WDCR_ENABLE;
 170                 writel(reg, gwdt->base + FTWDT010_WDCR);
 171         }
 172
 173         irq = platform_get_irq(pdev, 0);
 174         if (irq > 0) {
 175                 ret = devm_request_irq(dev, irq, ftwdt010_wdt_interrupt, 0,
 176                                        "watchdog bark", gwdt);
 177                 if (ret)
 178                         return ret;
 179                 gwdt->has_irq = true;
 180         }
 181
 182         ret = devm_watchdog_register_device(dev, &gwdt->wdd);
 183         if (ret)
 184                 return ret;
 185
 186         /* Set up platform driver data */
 187         platform_set_drvdata(pdev, gwdt);
 188         dev_info(dev, "FTWDT010 watchdog driver enabled\n");
 189
 190         return 0;
 191 }
 192
 193 static int __maybe_unused ftwdt010_wdt_suspend(struct device *dev)
 194 {
 195         struct ftwdt010_wdt *gwdt = dev_get_drvdata(dev);
 196         unsigned int reg;
 197
 198         reg = readw(gwdt->base + FTWDT010_WDCR);
 199         reg &= ~WDCR_ENABLE;
 200         writel(reg, gwdt->base + FTWDT010_WDCR);
 201
 202         return 0;
 203 }
 204
 205 static int __maybe_unused ftwdt010_wdt_resume(struct device *dev)
 206 {
 207         struct ftwdt010_wdt *gwdt = dev_get_drvdata(dev);
 208         unsigned int reg;
 209
 210         if (watchdog_active(&gwdt->wdd)) {
 211                 reg = readw(gwdt->base + FTWDT010_WDCR);
 212                 reg |= WDCR_ENABLE;
 213                 writel(reg, gwdt->base + FTWDT010_WDCR);
 214         }
 215
 216         return 0;
 217 }
 218
 219 static const struct dev_pm_ops ftwdt010_wdt_dev_pm_ops = {
 220         SET_SYSTEM_SLEEP_PM_OPS(ftwdt010_wdt_suspend,
 221                                 ftwdt010_wdt_resume)
 222 };
 223
 224 static const struct of_device_id ftwdt010_wdt_match[] = {
 225         { .compatible = "faraday,ftwdt010" },
 226         { .compatible = "cortina,gemini-watchdog" },
 227         {},
 228 };
 229 MODULE_DEVICE_TABLE(of, ftwdt010_wdt_match);
 230
 231 static struct platform_driver ftwdt010_wdt_driver = {
 232         .probe          = ftwdt010_wdt_probe,
 233         .driver         = {
 234                 .name   = "ftwdt010-wdt",
 235                 .of_match_table = ftwdt010_wdt_match,
 236                 .pm = &ftwdt010_wdt_dev_pm_ops,
 237         },
 238 };
 239 module_platform_driver(ftwdt010_wdt_driver);
 240 MODULE_AUTHOR("Linus Walleij");
 241 MODULE_DESCRIPTION("Watchdog driver for Faraday Technology FTWDT010");
 242 MODULE_LICENSE("GPL");