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/of_device.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 int ftwdt010_wdt_start(struct watchdog_device *wdd)
  51 {
  52         struct ftwdt010_wdt *gwdt = to_ftwdt010_wdt(wdd);
  53         u32 enable;
  54
  55         writel(wdd->timeout * WDT_CLOCK, gwdt->base + FTWDT010_WDLOAD);
  56         writel(WDRESTART_MAGIC, gwdt->base + FTWDT010_WDRESTART);
  57         /* set clock before enabling */
  58         enable = WDCR_CLOCK_5MHZ | WDCR_SYS_RST;
  59         writel(enable, gwdt->base + FTWDT010_WDCR);
  60         if (gwdt->has_irq)
  61                 enable |= WDCR_WDINTR;
  62         enable |= WDCR_ENABLE;
  63         writel(enable, gwdt->base + FTWDT010_WDCR);
  64
  65         return 0;
  66 }
  67
  68 static int ftwdt010_wdt_stop(struct watchdog_device *wdd)
  69 {
  70         struct ftwdt010_wdt *gwdt = to_ftwdt010_wdt(wdd);
  71
  72         writel(0, gwdt->base + FTWDT010_WDCR);
  73
  74         return 0;
  75 }
  76
  77 static int ftwdt010_wdt_ping(struct watchdog_device *wdd)
  78 {
  79         struct ftwdt010_wdt *gwdt = to_ftwdt010_wdt(wdd);
  80
  81         writel(WDRESTART_MAGIC, gwdt->base + FTWDT010_WDRESTART);
  82
  83         return 0;
  84 }
  85
  86 static int ftwdt010_wdt_set_timeout(struct watchdog_device *wdd,
  87                                   unsigned int timeout)
  88 {
  89         wdd->timeout = timeout;
  90         if (watchdog_active(wdd))
  91                 ftwdt010_wdt_start(wdd);
  92
  93         return 0;
  94 }
  95
  96 static irqreturn_t ftwdt010_wdt_interrupt(int irq, void *data)
  97 {
  98         struct ftwdt010_wdt *gwdt = data;
  99
 100         watchdog_notify_pretimeout(&gwdt->wdd);
 101
 102         return IRQ_HANDLED;
 103 }
 104
 105 static const struct watchdog_ops ftwdt010_wdt_ops = {
 106         .start          = ftwdt010_wdt_start,
 107         .stop           = ftwdt010_wdt_stop,
 108         .ping           = ftwdt010_wdt_ping,
 109         .set_timeout    = ftwdt010_wdt_set_timeout,
 110         .owner          = THIS_MODULE,
 111 };
 112
 113 static const struct watchdog_info ftwdt010_wdt_info = {
 114         .options        = WDIOF_KEEPALIVEPING
 115                         | WDIOF_MAGICCLOSE
 116                         | WDIOF_SETTIMEOUT,
 117         .identity       = KBUILD_MODNAME,
 118 };
 119
 120
 121 static int ftwdt010_wdt_probe(struct platform_device *pdev)
 122 {
 123         struct device *dev = &pdev->dev;
 124         struct ftwdt010_wdt *gwdt;
 125         unsigned int reg;
 126         int irq;
 127         int ret;
 128
 129         gwdt = devm_kzalloc(dev, sizeof(*gwdt), GFP_KERNEL);
 130         if (!gwdt)
 131                 return -ENOMEM;
 132
 133         gwdt->base = devm_platform_ioremap_resource(pdev, 0);
 134         if (IS_ERR(gwdt->base))
 135                 return PTR_ERR(gwdt->base);
 136
 137         gwdt->dev = dev;
 138         gwdt->wdd.info = &ftwdt010_wdt_info;
 139         gwdt->wdd.ops = &ftwdt010_wdt_ops;
 140         gwdt->wdd.min_timeout = 1;
 141         gwdt->wdd.max_timeout = 0xFFFFFFFF / WDT_CLOCK;
 142         gwdt->wdd.parent = dev;
 143
 144         /*
 145          * If 'timeout-sec' unspecified in devicetree, assume a 13 second
 146          * default.
 147          */
 148         gwdt->wdd.timeout = 13U;
 149         watchdog_init_timeout(&gwdt->wdd, 0, dev);
 150
 151         reg = readw(gwdt->base + FTWDT010_WDCR);
 152         if (reg & WDCR_ENABLE) {
 153                 /* Watchdog was enabled by the bootloader, disable it. */
 154                 reg &= ~WDCR_ENABLE;
 155                 writel(reg, gwdt->base + FTWDT010_WDCR);
 156         }
 157
 158         irq = platform_get_irq(pdev, 0);
 159         if (irq) {
 160                 ret = devm_request_irq(dev, irq, ftwdt010_wdt_interrupt, 0,
 161                                        "watchdog bark", gwdt);
 162                 if (ret)
 163                         return ret;
 164                 gwdt->has_irq = true;
 165         }
 166
 167         ret = devm_watchdog_register_device(dev, &gwdt->wdd);
 168         if (ret)
 169                 return ret;
 170
 171         /* Set up platform driver data */
 172         platform_set_drvdata(pdev, gwdt);
 173         dev_info(dev, "FTWDT010 watchdog driver enabled\n");
 174
 175         return 0;
 176 }
 177
 178 static int __maybe_unused ftwdt010_wdt_suspend(struct device *dev)
 179 {
 180         struct ftwdt010_wdt *gwdt = dev_get_drvdata(dev);
 181         unsigned int reg;
 182
 183         reg = readw(gwdt->base + FTWDT010_WDCR);
 184         reg &= ~WDCR_ENABLE;
 185         writel(reg, gwdt->base + FTWDT010_WDCR);
 186
 187         return 0;
 188 }
 189
 190 static int __maybe_unused ftwdt010_wdt_resume(struct device *dev)
 191 {
 192         struct ftwdt010_wdt *gwdt = dev_get_drvdata(dev);
 193         unsigned int reg;
 194
 195         if (watchdog_active(&gwdt->wdd)) {
 196                 reg = readw(gwdt->base + FTWDT010_WDCR);
 197                 reg |= WDCR_ENABLE;
 198                 writel(reg, gwdt->base + FTWDT010_WDCR);
 199         }
 200
 201         return 0;
 202 }
 203
 204 static const struct dev_pm_ops ftwdt010_wdt_dev_pm_ops = {
 205         SET_SYSTEM_SLEEP_PM_OPS(ftwdt010_wdt_suspend,
 206                                 ftwdt010_wdt_resume)
 207 };
 208
 209 #ifdef CONFIG_OF
 210 static const struct of_device_id ftwdt010_wdt_match[] = {
 211         { .compatible = "faraday,ftwdt010" },
 212         { .compatible = "cortina,gemini-watchdog" },
 213         {},
 214 };
 215 MODULE_DEVICE_TABLE(of, ftwdt010_wdt_match);
 216 #endif
 217
 218 static struct platform_driver ftwdt010_wdt_driver = {
 219         .probe          = ftwdt010_wdt_probe,
 220         .driver         = {
 221                 .name   = "ftwdt010-wdt",
 222                 .of_match_table = of_match_ptr(ftwdt010_wdt_match),
 223                 .pm = &ftwdt010_wdt_dev_pm_ops,
 224         },
 225 };
 226 module_platform_driver(ftwdt010_wdt_driver);
 227 MODULE_AUTHOR("Linus Walleij");
 228 MODULE_DESCRIPTION("Watchdog driver for Faraday Technology FTWDT010");
 229 MODULE_LICENSE("GPL");