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/i2c.h> 18 #include <linux/delay.h> 19 #include <linux/mfd/da9063/registers.h> 20 #include <linux/mfd/da9063/core.h> 21 #include <linux/property.h> 22 #include <linux/regmap.h> 23 24 /* 25 * Watchdog selector to timeout in seconds. 26 * 0: WDT disabled; 27 * others: timeout = 2048 ms * 2^(TWDSCALE-1). 28 */ 29 static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 }; 30 31 #define DA9063_TWDSCALE_DISABLE 0 32 #define DA9063_TWDSCALE_MIN 1 33 #define DA9063_TWDSCALE_MAX (ARRAY_SIZE(wdt_timeout) - 1) 34 #define DA9063_WDT_MIN_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MIN] 35 #define DA9063_WDT_MAX_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MAX] 36 #define DA9063_WDG_TIMEOUT wdt_timeout[3] 37 #define DA9063_RESET_PROTECTION_MS 256 38 39 static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs) 40 { 41 unsigned int i; 42 43 for (i = DA9063_TWDSCALE_MIN; i <= DA9063_TWDSCALE_MAX; i++) { 44 if (wdt_timeout[i] >= secs) 45 return i; 46 } 47 48 return DA9063_TWDSCALE_MAX; 49 } 50 51 /* 52 * Read the currently active timeout. 53 * Zero means the watchdog is disabled. 54 */ 55 static unsigned int da9063_wdt_read_timeout(struct da9063 *da9063) 56 { 57 unsigned int val; 58 59 regmap_read(da9063->regmap, DA9063_REG_CONTROL_D, &val); 60 61 return wdt_timeout[val & DA9063_TWDSCALE_MASK]; 62 } 63 64 static int da9063_wdt_disable_timer(struct da9063 *da9063) 65 { 66 return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D, 67 DA9063_TWDSCALE_MASK, 68 DA9063_TWDSCALE_DISABLE); 69 } 70 71 static int 72 da9063_wdt_update_timeout(struct da9063 *da9063, unsigned int timeout) 73 { 74 unsigned int regval; 75 int ret; 76 77 /* 78 * The watchdog triggers a reboot if a timeout value is already 79 * programmed because the timeout value combines two functions 80 * in one: indicating the counter limit and starting the watchdog. 81 * The watchdog must be disabled to be able to change the timeout 82 * value if the watchdog is already running. Then we can set the 83 * new timeout value which enables the watchdog again. 84 */ 85 ret = da9063_wdt_disable_timer(da9063); 86 if (ret) 87 return ret; 88 89 usleep_range(150, 300); 90 regval = da9063_wdt_timeout_to_sel(timeout); 91 92 return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D, 93 DA9063_TWDSCALE_MASK, regval); 94 } 95 96 static int da9063_wdt_start(struct watchdog_device *wdd) 97 { 98 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 99 int ret; 100 101 ret = da9063_wdt_update_timeout(da9063, wdd->timeout); 102 if (ret) 103 dev_err(da9063->dev, "Watchdog failed to start (err = %d)\n", 104 ret); 105 106 return ret; 107 } 108 109 static int da9063_wdt_stop(struct watchdog_device *wdd) 110 { 111 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 112 int ret; 113 114 ret = da9063_wdt_disable_timer(da9063); 115 if (ret) 116 dev_alert(da9063->dev, "Watchdog failed to stop (err = %d)\n", 117 ret); 118 119 return ret; 120 } 121 122 static int da9063_wdt_ping(struct watchdog_device *wdd) 123 { 124 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 125 int ret; 126 127 /* 128 * Prevent pings from occurring late in system poweroff/reboot sequence 129 * and possibly locking out restart handler from accessing i2c bus. 130 */ 131 if (system_state > SYSTEM_RUNNING) 132 return 0; 133 134 ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F, 135 DA9063_WATCHDOG); 136 if (ret) 137 dev_alert(da9063->dev, "Failed to ping the watchdog (err = %d)\n", 138 ret); 139 140 return ret; 141 } 142 143 static int da9063_wdt_set_timeout(struct watchdog_device *wdd, 144 unsigned int timeout) 145 { 146 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 147 int ret = 0; 148 149 /* 150 * There are two cases when a set_timeout() will be called: 151 * 1. The watchdog is off and someone wants to set the timeout for the 152 * further use. 153 * 2. The watchdog is already running and a new timeout value should be 154 * set. 155 * 156 * The watchdog can't store a timeout value not equal zero without 157 * enabling the watchdog, so the timeout must be buffered by the driver. 158 */ 159 if (watchdog_active(wdd)) 160 ret = da9063_wdt_update_timeout(da9063, timeout); 161 162 if (ret) 163 dev_err(da9063->dev, "Failed to set watchdog timeout (err = %d)\n", 164 ret); 165 else 166 wdd->timeout = wdt_timeout[da9063_wdt_timeout_to_sel(timeout)]; 167 168 return ret; 169 } 170 171 static int da9063_wdt_restart(struct watchdog_device *wdd, unsigned long action, 172 void *data) 173 { 174 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 175 struct i2c_client *client = to_i2c_client(da9063->dev); 176 union i2c_smbus_data msg; 177 int ret; 178 179 /* 180 * Don't use regmap because it is not atomic safe. Additionally, use 181 * unlocked flavor of i2c_smbus_xfer to avoid scenario where i2c bus 182 * might previously be locked by some process unable to release the 183 * lock due to interrupts already being disabled at this late stage. 184 */ 185 msg.byte = DA9063_SHUTDOWN; 186 ret = __i2c_smbus_xfer(client->adapter, client->addr, client->flags, 187 I2C_SMBUS_WRITE, DA9063_REG_CONTROL_F, 188 I2C_SMBUS_BYTE_DATA, &msg); 189 190 if (ret < 0) 191 dev_alert(da9063->dev, "Failed to shutdown (err = %d)\n", 192 ret); 193 194 /* wait for reset to assert... */ 195 mdelay(500); 196 197 return ret; 198 } 199 200 static const struct watchdog_info da9063_watchdog_info = { 201 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, 202 .identity = "DA9063 Watchdog", 203 }; 204 205 static const struct watchdog_ops da9063_watchdog_ops = { 206 .owner = THIS_MODULE, 207 .start = da9063_wdt_start, 208 .stop = da9063_wdt_stop, 209 .ping = da9063_wdt_ping, 210 .set_timeout = da9063_wdt_set_timeout, 211 .restart = da9063_wdt_restart, 212 }; 213 214 static int da9063_wdt_probe(struct platform_device *pdev) 215 { 216 struct device *dev = &pdev->dev; 217 struct da9063 *da9063; 218 struct watchdog_device *wdd; 219 unsigned int timeout; 220 221 if (!dev->parent) 222 return -EINVAL; 223 224 da9063 = dev_get_drvdata(dev->parent); 225 if (!da9063) 226 return -EINVAL; 227 228 wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL); 229 if (!wdd) 230 return -ENOMEM; 231 232 da9063->use_sw_pm = device_property_present(dev, "dlg,use-sw-pm"); 233 234 wdd->info = &da9063_watchdog_info; 235 wdd->ops = &da9063_watchdog_ops; 236 wdd->min_timeout = DA9063_WDT_MIN_TIMEOUT; 237 wdd->max_timeout = DA9063_WDT_MAX_TIMEOUT; 238 wdd->min_hw_heartbeat_ms = DA9063_RESET_PROTECTION_MS; 239 wdd->parent = dev; 240 wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS; 241 242 watchdog_set_restart_priority(wdd, 128); 243 watchdog_set_drvdata(wdd, da9063); 244 dev_set_drvdata(dev, wdd); 245 246 wdd->timeout = DA9063_WDG_TIMEOUT; 247 248 /* Use pre-configured timeout if watchdog is already running. */ 249 timeout = da9063_wdt_read_timeout(da9063); 250 if (timeout) 251 wdd->timeout = timeout; 252 253 /* Set timeout, maybe override it with DT value, scale it */ 254 watchdog_init_timeout(wdd, 0, dev); 255 da9063_wdt_set_timeout(wdd, wdd->timeout); 256 257 /* Update timeout if the watchdog is already running. */ 258 if (timeout) { 259 da9063_wdt_update_timeout(da9063, wdd->timeout); 260 set_bit(WDOG_HW_RUNNING, &wdd->status); 261 } 262 263 return devm_watchdog_register_device(dev, wdd); 264 } 265 266 static int da9063_wdt_suspend(struct device *dev) 267 { 268 struct watchdog_device *wdd = dev_get_drvdata(dev); 269 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 270 271 if (!da9063->use_sw_pm) 272 return 0; 273 274 if (watchdog_active(wdd)) 275 return da9063_wdt_stop(wdd); 276 277 return 0; 278 } 279 280 static int da9063_wdt_resume(struct device *dev) 281 { 282 struct watchdog_device *wdd = dev_get_drvdata(dev); 283 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 284 285 if (!da9063->use_sw_pm) 286 return 0; 287 288 if (watchdog_active(wdd)) 289 return da9063_wdt_start(wdd); 290 291 return 0; 292 } 293 294 static DEFINE_SIMPLE_DEV_PM_OPS(da9063_wdt_pm_ops, da9063_wdt_suspend, 295 da9063_wdt_resume); 296 297 static struct platform_driver da9063_wdt_driver = { 298 .probe = da9063_wdt_probe, 299 .driver = { 300 .name = DA9063_DRVNAME_WATCHDOG, 301 .pm = pm_sleep_ptr(&da9063_wdt_pm_ops), 302 }, 303 }; 304 module_platform_driver(da9063_wdt_driver); 305 306 MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>"); 307 MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063"); 308 MODULE_LICENSE("GPL"); 309 MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG); 310