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 /* 125 * Prevent pings from occurring late in system poweroff/reboot sequence 126 * and possibly locking out restart handler from accessing i2c bus. 127 */ 128 if (system_state > SYSTEM_RUNNING) 129 return 0; 130 131 ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F, 132 DA9063_WATCHDOG); 133 if (ret) 134 dev_alert(da9063->dev, "Failed to ping the watchdog (err = %d)\n", 135 ret); 136 137 return ret; 138 } 139 140 static int da9063_wdt_set_timeout(struct watchdog_device *wdd, 141 unsigned int timeout) 142 { 143 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 144 int ret = 0; 145 146 /* 147 * There are two cases when a set_timeout() will be called: 148 * 1. The watchdog is off and someone wants to set the timeout for the 149 * further use. 150 * 2. The watchdog is already running and a new timeout value should be 151 * set. 152 * 153 * The watchdog can't store a timeout value not equal zero without 154 * enabling the watchdog, so the timeout must be buffered by the driver. 155 */ 156 if (watchdog_active(wdd)) 157 ret = da9063_wdt_update_timeout(da9063, timeout); 158 159 if (ret) 160 dev_err(da9063->dev, "Failed to set watchdog timeout (err = %d)\n", 161 ret); 162 else 163 wdd->timeout = wdt_timeout[da9063_wdt_timeout_to_sel(timeout)]; 164 165 return ret; 166 } 167 168 static int da9063_wdt_restart(struct watchdog_device *wdd, unsigned long action, 169 void *data) 170 { 171 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 172 int ret; 173 174 ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F, 175 DA9063_SHUTDOWN); 176 if (ret) 177 dev_alert(da9063->dev, "Failed to shutdown (err = %d)\n", 178 ret); 179 180 return ret; 181 } 182 183 static const struct watchdog_info da9063_watchdog_info = { 184 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, 185 .identity = "DA9063 Watchdog", 186 }; 187 188 static const struct watchdog_ops da9063_watchdog_ops = { 189 .owner = THIS_MODULE, 190 .start = da9063_wdt_start, 191 .stop = da9063_wdt_stop, 192 .ping = da9063_wdt_ping, 193 .set_timeout = da9063_wdt_set_timeout, 194 .restart = da9063_wdt_restart, 195 }; 196 197 static int da9063_wdt_probe(struct platform_device *pdev) 198 { 199 struct device *dev = &pdev->dev; 200 struct da9063 *da9063; 201 struct watchdog_device *wdd; 202 unsigned int timeout; 203 204 if (!dev->parent) 205 return -EINVAL; 206 207 da9063 = dev_get_drvdata(dev->parent); 208 if (!da9063) 209 return -EINVAL; 210 211 wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL); 212 if (!wdd) 213 return -ENOMEM; 214 215 wdd->info = &da9063_watchdog_info; 216 wdd->ops = &da9063_watchdog_ops; 217 wdd->min_timeout = DA9063_WDT_MIN_TIMEOUT; 218 wdd->max_timeout = DA9063_WDT_MAX_TIMEOUT; 219 wdd->min_hw_heartbeat_ms = DA9063_RESET_PROTECTION_MS; 220 wdd->parent = dev; 221 wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS; 222 223 watchdog_set_restart_priority(wdd, 128); 224 watchdog_set_drvdata(wdd, da9063); 225 226 wdd->timeout = DA9063_WDG_TIMEOUT; 227 228 /* Use pre-configured timeout if watchdog is already running. */ 229 timeout = da9063_wdt_read_timeout(da9063); 230 if (timeout) 231 wdd->timeout = timeout; 232 233 /* Set timeout, maybe override it with DT value, scale it */ 234 watchdog_init_timeout(wdd, 0, dev); 235 da9063_wdt_set_timeout(wdd, wdd->timeout); 236 237 /* Update timeout if the watchdog is already running. */ 238 if (timeout) { 239 da9063_wdt_update_timeout(da9063, wdd->timeout); 240 set_bit(WDOG_HW_RUNNING, &wdd->status); 241 } 242 243 return devm_watchdog_register_device(dev, wdd); 244 } 245 246 static struct platform_driver da9063_wdt_driver = { 247 .probe = da9063_wdt_probe, 248 .driver = { 249 .name = DA9063_DRVNAME_WATCHDOG, 250 }, 251 }; 252 module_platform_driver(da9063_wdt_driver); 253 254 MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>"); 255 MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063"); 256 MODULE_LICENSE("GPL"); 257 MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG); 258