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.h> 17 #include <linux/of_gpio.h> 18 #include <linux/delay.h> 19 #include <linux/bitops.h> 20 21 #define NUM_GPIOS 6 22 23 enum 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 32 struct a21_wdt_drv { 33 struct watchdog_device wdt; 34 struct mutex lock; 35 unsigned gpios[NUM_GPIOS]; 36 }; 37 38 static bool nowayout = WATCHDOG_NOWAYOUT; 39 module_param(nowayout, bool, 0); 40 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" 41 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 42 43 static unsigned int a21_wdt_get_bootstatus(struct a21_wdt_drv *drv) 44 { 45 int reset = 0; 46 47 reset |= gpio_get_value(drv->gpios[GPIO_WD_RST0]) ? (1 << 0) : 0; 48 reset |= gpio_get_value(drv->gpios[GPIO_WD_RST1]) ? (1 << 1) : 0; 49 reset |= gpio_get_value(drv->gpios[GPIO_WD_RST2]) ? (1 << 2) : 0; 50 51 return reset; 52 } 53 54 static int a21_wdt_start(struct watchdog_device *wdt) 55 { 56 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt); 57 58 mutex_lock(&drv->lock); 59 60 gpio_set_value(drv->gpios[GPIO_WD_ENAB], 1); 61 62 mutex_unlock(&drv->lock); 63 64 return 0; 65 } 66 67 static int a21_wdt_stop(struct watchdog_device *wdt) 68 { 69 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt); 70 71 mutex_lock(&drv->lock); 72 73 gpio_set_value(drv->gpios[GPIO_WD_ENAB], 0); 74 75 mutex_unlock(&drv->lock); 76 77 return 0; 78 } 79 80 static int a21_wdt_ping(struct watchdog_device *wdt) 81 { 82 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt); 83 84 mutex_lock(&drv->lock); 85 86 gpio_set_value(drv->gpios[GPIO_WD_TRIG], 0); 87 ndelay(10); 88 gpio_set_value(drv->gpios[GPIO_WD_TRIG], 1); 89 90 mutex_unlock(&drv->lock); 91 92 return 0; 93 } 94 95 static int a21_wdt_set_timeout(struct watchdog_device *wdt, 96 unsigned int timeout) 97 { 98 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt); 99 100 if (timeout != 1 && timeout != 30) { 101 dev_err(wdt->parent, "Only 1 and 30 allowed as timeout\n"); 102 return -EINVAL; 103 } 104 105 if (timeout == 30 && wdt->timeout == 1) { 106 dev_err(wdt->parent, 107 "Transition from fast to slow mode not allowed\n"); 108 return -EINVAL; 109 } 110 111 mutex_lock(&drv->lock); 112 113 if (timeout == 1) 114 gpio_set_value(drv->gpios[GPIO_WD_FAST], 1); 115 else 116 gpio_set_value(drv->gpios[GPIO_WD_FAST], 0); 117 118 wdt->timeout = timeout; 119 120 mutex_unlock(&drv->lock); 121 122 return 0; 123 } 124 125 static const struct watchdog_info a21_wdt_info = { 126 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, 127 .identity = "MEN A21 Watchdog", 128 }; 129 130 static const struct watchdog_ops a21_wdt_ops = { 131 .owner = THIS_MODULE, 132 .start = a21_wdt_start, 133 .stop = a21_wdt_stop, 134 .ping = a21_wdt_ping, 135 .set_timeout = a21_wdt_set_timeout, 136 }; 137 138 static struct watchdog_device a21_wdt = { 139 .info = &a21_wdt_info, 140 .ops = &a21_wdt_ops, 141 .min_timeout = 1, 142 .max_timeout = 30, 143 }; 144 145 static int a21_wdt_probe(struct platform_device *pdev) 146 { 147 struct device_node *node; 148 struct a21_wdt_drv *drv; 149 unsigned int reset = 0; 150 int num_gpios; 151 int ret; 152 int i; 153 154 drv = devm_kzalloc(&pdev->dev, sizeof(struct a21_wdt_drv), GFP_KERNEL); 155 if (!drv) 156 return -ENOMEM; 157 158 /* Fill GPIO pin array */ 159 node = pdev->dev.of_node; 160 161 num_gpios = of_gpio_count(node); 162 if (num_gpios != NUM_GPIOS) { 163 dev_err(&pdev->dev, "gpios DT property wrong, got %d want %d", 164 num_gpios, NUM_GPIOS); 165 return -ENODEV; 166 } 167 168 for (i = 0; i < num_gpios; i++) { 169 int val; 170 171 val = of_get_gpio(node, i); 172 if (val < 0) 173 return val; 174 175 drv->gpios[i] = val; 176 } 177 178 /* Request the used GPIOs */ 179 for (i = 0; i < num_gpios; i++) { 180 ret = devm_gpio_request(&pdev->dev, drv->gpios[i], 181 "MEN A21 Watchdog"); 182 if (ret) 183 return ret; 184 185 if (i < GPIO_WD_RST0) 186 ret = gpio_direction_output(drv->gpios[i], 187 gpio_get_value(drv->gpios[i])); 188 else /* GPIO_WD_RST[0..2] are inputs */ 189 ret = gpio_direction_input(drv->gpios[i]); 190 if (ret) 191 return ret; 192 } 193 194 mutex_init(&drv->lock); 195 watchdog_init_timeout(&a21_wdt, 30, &pdev->dev); 196 watchdog_set_nowayout(&a21_wdt, nowayout); 197 watchdog_set_drvdata(&a21_wdt, drv); 198 a21_wdt.parent = &pdev->dev; 199 200 reset = a21_wdt_get_bootstatus(drv); 201 if (reset == 2) 202 a21_wdt.bootstatus |= WDIOF_EXTERN1; 203 else if (reset == 4) 204 a21_wdt.bootstatus |= WDIOF_CARDRESET; 205 else if (reset == 5) 206 a21_wdt.bootstatus |= WDIOF_POWERUNDER; 207 else if (reset == 7) 208 a21_wdt.bootstatus |= WDIOF_EXTERN2; 209 210 drv->wdt = a21_wdt; 211 dev_set_drvdata(&pdev->dev, drv); 212 213 ret = devm_watchdog_register_device(&pdev->dev, &a21_wdt); 214 if (ret) { 215 dev_err(&pdev->dev, "Cannot register watchdog device\n"); 216 return ret; 217 } 218 219 dev_info(&pdev->dev, "MEN A21 watchdog timer driver enabled\n"); 220 221 return 0; 222 } 223 224 static void a21_wdt_shutdown(struct platform_device *pdev) 225 { 226 struct a21_wdt_drv *drv = dev_get_drvdata(&pdev->dev); 227 228 gpio_set_value(drv->gpios[GPIO_WD_ENAB], 0); 229 } 230 231 static const struct of_device_id a21_wdt_ids[] = { 232 { .compatible = "men,a021-wdt" }, 233 { }, 234 }; 235 MODULE_DEVICE_TABLE(of, a21_wdt_ids); 236 237 static struct platform_driver a21_wdt_driver = { 238 .probe = a21_wdt_probe, 239 .shutdown = a21_wdt_shutdown, 240 .driver = { 241 .name = "a21-watchdog", 242 .of_match_table = a21_wdt_ids, 243 }, 244 }; 245 246 module_platform_driver(a21_wdt_driver); 247 248 MODULE_AUTHOR("MEN Mikro Elektronik"); 249 MODULE_DESCRIPTION("MEN A21 Watchdog"); 250 MODULE_LICENSE("GPL"); 251 MODULE_ALIAS("platform:a21-watchdog"); 252