1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Watchdog driver for DA9063 PMICs. 4 * 5 * Copyright(c) 2012 Dialog Semiconductor Ltd. 6 * 7 * Author: Mariusz Wojtasik <mariusz.wojtasik@diasemi.com> 8 * 9 */ 10 11 #include <linux/kernel.h> 12 #include <linux/module.h> 13 #include <linux/watchdog.h> 14 #include <linux/platform_device.h> 15 #include <linux/uaccess.h> 16 #include <linux/slab.h> 17 #include <linux/delay.h> 18 #include <linux/mfd/da9063/registers.h> 19 #include <linux/mfd/da9063/core.h> 20 #include <linux/regmap.h> 21 22 /* 23 * Watchdog selector to timeout in seconds. 24 * 0: WDT disabled; 25 * others: timeout = 2048 ms * 2^(TWDSCALE-1). 26 */ 27 static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 }; 28 #define DA9063_TWDSCALE_DISABLE 0 29 #define DA9063_TWDSCALE_MIN 1 30 #define DA9063_TWDSCALE_MAX (ARRAY_SIZE(wdt_timeout) - 1) 31 #define DA9063_WDT_MIN_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MIN] 32 #define DA9063_WDT_MAX_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MAX] 33 #define DA9063_WDG_TIMEOUT wdt_timeout[3] 34 #define DA9063_RESET_PROTECTION_MS 256 35 36 static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs) 37 { 38 unsigned int i; 39 40 for (i = DA9063_TWDSCALE_MIN; i <= DA9063_TWDSCALE_MAX; i++) { 41 if (wdt_timeout[i] >= secs) 42 return i; 43 } 44 45 return DA9063_TWDSCALE_MAX; 46 } 47 48 /* 49 * Read the currently active timeout. 50 * Zero means the watchdog is disabled. 51 */ 52 static unsigned int da9063_wdt_read_timeout(struct da9063 *da9063) 53 { 54 unsigned int val; 55 56 regmap_read(da9063->regmap, DA9063_REG_CONTROL_D, &val); 57 58 return wdt_timeout[val & DA9063_TWDSCALE_MASK]; 59 } 60 61 static int da9063_wdt_disable_timer(struct da9063 *da9063) 62 { 63 return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D, 64 DA9063_TWDSCALE_MASK, 65 DA9063_TWDSCALE_DISABLE); 66 } 67 68 static int 69 da9063_wdt_update_timeout(struct da9063 *da9063, unsigned int timeout) 70 { 71 unsigned int regval; 72 int ret; 73 74 /* 75 * The watchdog triggers a reboot if a timeout value is already 76 * programmed because the timeout value combines two functions 77 * in one: indicating the counter limit and starting the watchdog. 78 * The watchdog must be disabled to be able to change the timeout 79 * value if the watchdog is already running. Then we can set the 80 * new timeout value which enables the watchdog again. 81 */ 82 ret = da9063_wdt_disable_timer(da9063); 83 if (ret) 84 return ret; 85 86 usleep_range(150, 300); 87 regval = da9063_wdt_timeout_to_sel(timeout); 88 89 return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D, 90 DA9063_TWDSCALE_MASK, regval); 91 } 92 93 static int da9063_wdt_start(struct watchdog_device *wdd) 94 { 95 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 96 int ret; 97 98 ret = da9063_wdt_update_timeout(da9063, wdd->timeout); 99 if (ret) 100 dev_err(da9063->dev, "Watchdog failed to start (err = %d)\n", 101 ret); 102 103 return ret; 104 } 105 106 static int da9063_wdt_stop(struct watchdog_device *wdd) 107 { 108 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 109 int ret; 110 111 ret = da9063_wdt_disable_timer(da9063); 112 if (ret) 113 dev_alert(da9063->dev, "Watchdog failed to stop (err = %d)\n", 114 ret); 115 116 return ret; 117 } 118 119 static int da9063_wdt_ping(struct watchdog_device *wdd) 120 { 121 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 122 int ret; 123 124 ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F, 125 DA9063_WATCHDOG); 126 if (ret) 127 dev_alert(da9063->dev, "Failed to ping the watchdog (err = %d)\n", 128 ret); 129 130 return ret; 131 } 132 133 static int da9063_wdt_set_timeout(struct watchdog_device *wdd, 134 unsigned int timeout) 135 { 136 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 137 int ret = 0; 138 139 /* 140 * There are two cases when a set_timeout() will be called: 141 * 1. The watchdog is off and someone wants to set the timeout for the 142 * further use. 143 * 2. The watchdog is already running and a new timeout value should be 144 * set. 145 * 146 * The watchdog can't store a timeout value not equal zero without 147 * enabling the watchdog, so the timeout must be buffered by the driver. 148 */ 149 if (watchdog_active(wdd)) 150 ret = da9063_wdt_update_timeout(da9063, timeout); 151 152 if (ret) 153 dev_err(da9063->dev, "Failed to set watchdog timeout (err = %d)\n", 154 ret); 155 else 156 wdd->timeout = wdt_timeout[da9063_wdt_timeout_to_sel(timeout)]; 157 158 return ret; 159 } 160 161 static int da9063_wdt_restart(struct watchdog_device *wdd, unsigned long action, 162 void *data) 163 { 164 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 165 int ret; 166 167 ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F, 168 DA9063_SHUTDOWN); 169 if (ret) 170 dev_alert(da9063->dev, "Failed to shutdown (err = %d)\n", 171 ret); 172 173 return ret; 174 } 175 176 static const struct watchdog_info da9063_watchdog_info = { 177 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, 178 .identity = "DA9063 Watchdog", 179 }; 180 181 static const struct watchdog_ops da9063_watchdog_ops = { 182 .owner = THIS_MODULE, 183 .start = da9063_wdt_start, 184 .stop = da9063_wdt_stop, 185 .ping = da9063_wdt_ping, 186 .set_timeout = da9063_wdt_set_timeout, 187 .restart = da9063_wdt_restart, 188 }; 189 190 static int da9063_wdt_probe(struct platform_device *pdev) 191 { 192 struct device *dev = &pdev->dev; 193 struct da9063 *da9063; 194 struct watchdog_device *wdd; 195 unsigned int timeout; 196 197 if (!dev->parent) 198 return -EINVAL; 199 200 da9063 = dev_get_drvdata(dev->parent); 201 if (!da9063) 202 return -EINVAL; 203 204 wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL); 205 if (!wdd) 206 return -ENOMEM; 207 208 wdd->info = &da9063_watchdog_info; 209 wdd->ops = &da9063_watchdog_ops; 210 wdd->min_timeout = DA9063_WDT_MIN_TIMEOUT; 211 wdd->max_timeout = DA9063_WDT_MAX_TIMEOUT; 212 wdd->min_hw_heartbeat_ms = DA9063_RESET_PROTECTION_MS; 213 wdd->parent = dev; 214 wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS; 215 216 watchdog_set_restart_priority(wdd, 128); 217 watchdog_set_drvdata(wdd, da9063); 218 219 wdd->timeout = DA9063_WDG_TIMEOUT; 220 221 /* Use pre-configured timeout if watchdog is already running. */ 222 timeout = da9063_wdt_read_timeout(da9063); 223 if (timeout) 224 wdd->timeout = timeout; 225 226 /* Set timeout, maybe override it with DT value, scale it */ 227 watchdog_init_timeout(wdd, 0, dev); 228 da9063_wdt_set_timeout(wdd, wdd->timeout); 229 230 /* Update timeout if the watchdog is already running. */ 231 if (timeout) { 232 da9063_wdt_update_timeout(da9063, wdd->timeout); 233 set_bit(WDOG_HW_RUNNING, &wdd->status); 234 } 235 236 return devm_watchdog_register_device(dev, wdd); 237 } 238 239 static struct platform_driver da9063_wdt_driver = { 240 .probe = da9063_wdt_probe, 241 .driver = { 242 .name = DA9063_DRVNAME_WATCHDOG, 243 }, 244 }; 245 module_platform_driver(da9063_wdt_driver); 246 247 MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>"); 248 MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063"); 249 MODULE_LICENSE("GPL"); 250 MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG); 251