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 dev_err(dev, "failed to register watchdog\n"); 170 return ret; 171 } 172 173 /* Set up platform driver data */ 174 platform_set_drvdata(pdev, gwdt); 175 dev_info(dev, "FTWDT010 watchdog driver enabled\n"); 176 177 return 0; 178 } 179 180 static int __maybe_unused ftwdt010_wdt_suspend(struct device *dev) 181 { 182 struct ftwdt010_wdt *gwdt = dev_get_drvdata(dev); 183 unsigned int reg; 184 185 reg = readw(gwdt->base + FTWDT010_WDCR); 186 reg &= ~WDCR_ENABLE; 187 writel(reg, gwdt->base + FTWDT010_WDCR); 188 189 return 0; 190 } 191 192 static int __maybe_unused ftwdt010_wdt_resume(struct device *dev) 193 { 194 struct ftwdt010_wdt *gwdt = dev_get_drvdata(dev); 195 unsigned int reg; 196 197 if (watchdog_active(&gwdt->wdd)) { 198 reg = readw(gwdt->base + FTWDT010_WDCR); 199 reg |= WDCR_ENABLE; 200 writel(reg, gwdt->base + FTWDT010_WDCR); 201 } 202 203 return 0; 204 } 205 206 static const struct dev_pm_ops ftwdt010_wdt_dev_pm_ops = { 207 SET_SYSTEM_SLEEP_PM_OPS(ftwdt010_wdt_suspend, 208 ftwdt010_wdt_resume) 209 }; 210 211 #ifdef CONFIG_OF 212 static const struct of_device_id ftwdt010_wdt_match[] = { 213 { .compatible = "faraday,ftwdt010" }, 214 { .compatible = "cortina,gemini-watchdog" }, 215 {}, 216 }; 217 MODULE_DEVICE_TABLE(of, ftwdt010_wdt_match); 218 #endif 219 220 static struct platform_driver ftwdt010_wdt_driver = { 221 .probe = ftwdt010_wdt_probe, 222 .driver = { 223 .name = "ftwdt010-wdt", 224 .of_match_table = of_match_ptr(ftwdt010_wdt_match), 225 .pm = &ftwdt010_wdt_dev_pm_ops, 226 }, 227 }; 228 module_platform_driver(ftwdt010_wdt_driver); 229 MODULE_AUTHOR("Linus Walleij"); 230 MODULE_DESCRIPTION("Watchdog driver for Faraday Technology FTWDT010"); 231 MODULE_LICENSE("GPL"); 232