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 static bool use_sw_pm; 31 32 #define DA9063_TWDSCALE_DISABLE 0 33 #define DA9063_TWDSCALE_MIN 1 34 #define DA9063_TWDSCALE_MAX (ARRAY_SIZE(wdt_timeout) - 1) 35 #define DA9063_WDT_MIN_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MIN] 36 #define DA9063_WDT_MAX_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MAX] 37 #define DA9063_WDG_TIMEOUT wdt_timeout[3] 38 #define DA9063_RESET_PROTECTION_MS 256 39 40 static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs) 41 { 42 unsigned int i; 43 44 for (i = DA9063_TWDSCALE_MIN; i <= DA9063_TWDSCALE_MAX; i++) { 45 if (wdt_timeout[i] >= secs) 46 return i; 47 } 48 49 return DA9063_TWDSCALE_MAX; 50 } 51 52 /* 53 * Read the currently active timeout. 54 * Zero means the watchdog is disabled. 55 */ 56 static unsigned int da9063_wdt_read_timeout(struct da9063 *da9063) 57 { 58 unsigned int val; 59 60 regmap_read(da9063->regmap, DA9063_REG_CONTROL_D, &val); 61 62 return wdt_timeout[val & DA9063_TWDSCALE_MASK]; 63 } 64 65 static int da9063_wdt_disable_timer(struct da9063 *da9063) 66 { 67 return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D, 68 DA9063_TWDSCALE_MASK, 69 DA9063_TWDSCALE_DISABLE); 70 } 71 72 static int 73 da9063_wdt_update_timeout(struct da9063 *da9063, unsigned int timeout) 74 { 75 unsigned int regval; 76 int ret; 77 78 /* 79 * The watchdog triggers a reboot if a timeout value is already 80 * programmed because the timeout value combines two functions 81 * in one: indicating the counter limit and starting the watchdog. 82 * The watchdog must be disabled to be able to change the timeout 83 * value if the watchdog is already running. Then we can set the 84 * new timeout value which enables the watchdog again. 85 */ 86 ret = da9063_wdt_disable_timer(da9063); 87 if (ret) 88 return ret; 89 90 usleep_range(150, 300); 91 regval = da9063_wdt_timeout_to_sel(timeout); 92 93 return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D, 94 DA9063_TWDSCALE_MASK, regval); 95 } 96 97 static int da9063_wdt_start(struct watchdog_device *wdd) 98 { 99 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 100 int ret; 101 102 ret = da9063_wdt_update_timeout(da9063, wdd->timeout); 103 if (ret) 104 dev_err(da9063->dev, "Watchdog failed to start (err = %d)\n", 105 ret); 106 107 return ret; 108 } 109 110 static int da9063_wdt_stop(struct watchdog_device *wdd) 111 { 112 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 113 int ret; 114 115 ret = da9063_wdt_disable_timer(da9063); 116 if (ret) 117 dev_alert(da9063->dev, "Watchdog failed to stop (err = %d)\n", 118 ret); 119 120 return ret; 121 } 122 123 static int da9063_wdt_ping(struct watchdog_device *wdd) 124 { 125 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 126 int ret; 127 128 /* 129 * Prevent pings from occurring late in system poweroff/reboot sequence 130 * and possibly locking out restart handler from accessing i2c bus. 131 */ 132 if (system_state > SYSTEM_RUNNING) 133 return 0; 134 135 ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F, 136 DA9063_WATCHDOG); 137 if (ret) 138 dev_alert(da9063->dev, "Failed to ping the watchdog (err = %d)\n", 139 ret); 140 141 return ret; 142 } 143 144 static int da9063_wdt_set_timeout(struct watchdog_device *wdd, 145 unsigned int timeout) 146 { 147 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 148 int ret = 0; 149 150 /* 151 * There are two cases when a set_timeout() will be called: 152 * 1. The watchdog is off and someone wants to set the timeout for the 153 * further use. 154 * 2. The watchdog is already running and a new timeout value should be 155 * set. 156 * 157 * The watchdog can't store a timeout value not equal zero without 158 * enabling the watchdog, so the timeout must be buffered by the driver. 159 */ 160 if (watchdog_active(wdd)) 161 ret = da9063_wdt_update_timeout(da9063, timeout); 162 163 if (ret) 164 dev_err(da9063->dev, "Failed to set watchdog timeout (err = %d)\n", 165 ret); 166 else 167 wdd->timeout = wdt_timeout[da9063_wdt_timeout_to_sel(timeout)]; 168 169 return ret; 170 } 171 172 static int da9063_wdt_restart(struct watchdog_device *wdd, unsigned long action, 173 void *data) 174 { 175 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 176 struct i2c_client *client = to_i2c_client(da9063->dev); 177 int ret; 178 179 /* Don't use regmap because it is not atomic safe */ 180 ret = i2c_smbus_write_byte_data(client, DA9063_REG_CONTROL_F, 181 DA9063_SHUTDOWN); 182 if (ret < 0) 183 dev_alert(da9063->dev, "Failed to shutdown (err = %d)\n", 184 ret); 185 186 /* wait for reset to assert... */ 187 mdelay(500); 188 189 return ret; 190 } 191 192 static const struct watchdog_info da9063_watchdog_info = { 193 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, 194 .identity = "DA9063 Watchdog", 195 }; 196 197 static const struct watchdog_ops da9063_watchdog_ops = { 198 .owner = THIS_MODULE, 199 .start = da9063_wdt_start, 200 .stop = da9063_wdt_stop, 201 .ping = da9063_wdt_ping, 202 .set_timeout = da9063_wdt_set_timeout, 203 .restart = da9063_wdt_restart, 204 }; 205 206 static int da9063_wdt_probe(struct platform_device *pdev) 207 { 208 struct device *dev = &pdev->dev; 209 struct da9063 *da9063; 210 struct watchdog_device *wdd; 211 unsigned int timeout; 212 213 if (!dev->parent) 214 return -EINVAL; 215 216 da9063 = dev_get_drvdata(dev->parent); 217 if (!da9063) 218 return -EINVAL; 219 220 wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL); 221 if (!wdd) 222 return -ENOMEM; 223 224 use_sw_pm = device_property_present(dev, "dlg,use-sw-pm"); 225 226 wdd->info = &da9063_watchdog_info; 227 wdd->ops = &da9063_watchdog_ops; 228 wdd->min_timeout = DA9063_WDT_MIN_TIMEOUT; 229 wdd->max_timeout = DA9063_WDT_MAX_TIMEOUT; 230 wdd->min_hw_heartbeat_ms = DA9063_RESET_PROTECTION_MS; 231 wdd->parent = dev; 232 wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS; 233 234 watchdog_set_restart_priority(wdd, 128); 235 watchdog_set_drvdata(wdd, da9063); 236 dev_set_drvdata(dev, wdd); 237 238 wdd->timeout = DA9063_WDG_TIMEOUT; 239 240 /* Use pre-configured timeout if watchdog is already running. */ 241 timeout = da9063_wdt_read_timeout(da9063); 242 if (timeout) 243 wdd->timeout = timeout; 244 245 /* Set timeout, maybe override it with DT value, scale it */ 246 watchdog_init_timeout(wdd, 0, dev); 247 da9063_wdt_set_timeout(wdd, wdd->timeout); 248 249 /* Update timeout if the watchdog is already running. */ 250 if (timeout) { 251 da9063_wdt_update_timeout(da9063, wdd->timeout); 252 set_bit(WDOG_HW_RUNNING, &wdd->status); 253 } 254 255 return devm_watchdog_register_device(dev, wdd); 256 } 257 258 static int __maybe_unused da9063_wdt_suspend(struct device *dev) 259 { 260 struct watchdog_device *wdd = dev_get_drvdata(dev); 261 262 if (!use_sw_pm) 263 return 0; 264 265 if (watchdog_active(wdd)) 266 return da9063_wdt_stop(wdd); 267 268 return 0; 269 } 270 271 static int __maybe_unused da9063_wdt_resume(struct device *dev) 272 { 273 struct watchdog_device *wdd = dev_get_drvdata(dev); 274 275 if (!use_sw_pm) 276 return 0; 277 278 if (watchdog_active(wdd)) 279 return da9063_wdt_start(wdd); 280 281 return 0; 282 } 283 284 static SIMPLE_DEV_PM_OPS(da9063_wdt_pm_ops, 285 da9063_wdt_suspend, da9063_wdt_resume); 286 287 static struct platform_driver da9063_wdt_driver = { 288 .probe = da9063_wdt_probe, 289 .driver = { 290 .name = DA9063_DRVNAME_WATCHDOG, 291 .pm = &da9063_wdt_pm_ops, 292 }, 293 }; 294 module_platform_driver(da9063_wdt_driver); 295 296 MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>"); 297 MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063"); 298 MODULE_LICENSE("GPL"); 299 MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG); 300