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/regmap.h> 22 23 /* 24 * Watchdog selector to timeout in seconds. 25 * 0: WDT disabled; 26 * others: timeout = 2048 ms * 2^(TWDSCALE-1). 27 */ 28 static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 }; 29 #define DA9063_TWDSCALE_DISABLE 0 30 #define DA9063_TWDSCALE_MIN 1 31 #define DA9063_TWDSCALE_MAX (ARRAY_SIZE(wdt_timeout) - 1) 32 #define DA9063_WDT_MIN_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MIN] 33 #define DA9063_WDT_MAX_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MAX] 34 #define DA9063_WDG_TIMEOUT wdt_timeout[3] 35 #define DA9063_RESET_PROTECTION_MS 256 36 37 static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs) 38 { 39 unsigned int i; 40 41 for (i = DA9063_TWDSCALE_MIN; i <= DA9063_TWDSCALE_MAX; i++) { 42 if (wdt_timeout[i] >= secs) 43 return i; 44 } 45 46 return DA9063_TWDSCALE_MAX; 47 } 48 49 /* 50 * Read the currently active timeout. 51 * Zero means the watchdog is disabled. 52 */ 53 static unsigned int da9063_wdt_read_timeout(struct da9063 *da9063) 54 { 55 unsigned int val; 56 57 regmap_read(da9063->regmap, DA9063_REG_CONTROL_D, &val); 58 59 return wdt_timeout[val & DA9063_TWDSCALE_MASK]; 60 } 61 62 static int da9063_wdt_disable_timer(struct da9063 *da9063) 63 { 64 return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D, 65 DA9063_TWDSCALE_MASK, 66 DA9063_TWDSCALE_DISABLE); 67 } 68 69 static int 70 da9063_wdt_update_timeout(struct da9063 *da9063, unsigned int timeout) 71 { 72 unsigned int regval; 73 int ret; 74 75 /* 76 * The watchdog triggers a reboot if a timeout value is already 77 * programmed because the timeout value combines two functions 78 * in one: indicating the counter limit and starting the watchdog. 79 * The watchdog must be disabled to be able to change the timeout 80 * value if the watchdog is already running. Then we can set the 81 * new timeout value which enables the watchdog again. 82 */ 83 ret = da9063_wdt_disable_timer(da9063); 84 if (ret) 85 return ret; 86 87 usleep_range(150, 300); 88 regval = da9063_wdt_timeout_to_sel(timeout); 89 90 return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D, 91 DA9063_TWDSCALE_MASK, regval); 92 } 93 94 static int da9063_wdt_start(struct watchdog_device *wdd) 95 { 96 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 97 int ret; 98 99 ret = da9063_wdt_update_timeout(da9063, wdd->timeout); 100 if (ret) 101 dev_err(da9063->dev, "Watchdog failed to start (err = %d)\n", 102 ret); 103 104 return ret; 105 } 106 107 static int da9063_wdt_stop(struct watchdog_device *wdd) 108 { 109 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 110 int ret; 111 112 ret = da9063_wdt_disable_timer(da9063); 113 if (ret) 114 dev_alert(da9063->dev, "Watchdog failed to stop (err = %d)\n", 115 ret); 116 117 return ret; 118 } 119 120 static int da9063_wdt_ping(struct watchdog_device *wdd) 121 { 122 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 123 int ret; 124 125 /* 126 * Prevent pings from occurring late in system poweroff/reboot sequence 127 * and possibly locking out restart handler from accessing i2c bus. 128 */ 129 if (system_state > SYSTEM_RUNNING) 130 return 0; 131 132 ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F, 133 DA9063_WATCHDOG); 134 if (ret) 135 dev_alert(da9063->dev, "Failed to ping the watchdog (err = %d)\n", 136 ret); 137 138 return ret; 139 } 140 141 static int da9063_wdt_set_timeout(struct watchdog_device *wdd, 142 unsigned int timeout) 143 { 144 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 145 int ret = 0; 146 147 /* 148 * There are two cases when a set_timeout() will be called: 149 * 1. The watchdog is off and someone wants to set the timeout for the 150 * further use. 151 * 2. The watchdog is already running and a new timeout value should be 152 * set. 153 * 154 * The watchdog can't store a timeout value not equal zero without 155 * enabling the watchdog, so the timeout must be buffered by the driver. 156 */ 157 if (watchdog_active(wdd)) 158 ret = da9063_wdt_update_timeout(da9063, timeout); 159 160 if (ret) 161 dev_err(da9063->dev, "Failed to set watchdog timeout (err = %d)\n", 162 ret); 163 else 164 wdd->timeout = wdt_timeout[da9063_wdt_timeout_to_sel(timeout)]; 165 166 return ret; 167 } 168 169 static int da9063_wdt_restart(struct watchdog_device *wdd, unsigned long action, 170 void *data) 171 { 172 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 173 struct i2c_client *client = to_i2c_client(da9063->dev); 174 int ret; 175 176 /* Don't use regmap because it is not atomic safe */ 177 ret = i2c_smbus_write_byte_data(client, DA9063_REG_CONTROL_F, 178 DA9063_SHUTDOWN); 179 if (ret < 0) 180 dev_alert(da9063->dev, "Failed to shutdown (err = %d)\n", 181 ret); 182 183 /* wait for reset to assert... */ 184 mdelay(500); 185 186 return ret; 187 } 188 189 static const struct watchdog_info da9063_watchdog_info = { 190 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, 191 .identity = "DA9063 Watchdog", 192 }; 193 194 static const struct watchdog_ops da9063_watchdog_ops = { 195 .owner = THIS_MODULE, 196 .start = da9063_wdt_start, 197 .stop = da9063_wdt_stop, 198 .ping = da9063_wdt_ping, 199 .set_timeout = da9063_wdt_set_timeout, 200 .restart = da9063_wdt_restart, 201 }; 202 203 static int da9063_wdt_probe(struct platform_device *pdev) 204 { 205 struct device *dev = &pdev->dev; 206 struct da9063 *da9063; 207 struct watchdog_device *wdd; 208 unsigned int timeout; 209 210 if (!dev->parent) 211 return -EINVAL; 212 213 da9063 = dev_get_drvdata(dev->parent); 214 if (!da9063) 215 return -EINVAL; 216 217 wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL); 218 if (!wdd) 219 return -ENOMEM; 220 221 wdd->info = &da9063_watchdog_info; 222 wdd->ops = &da9063_watchdog_ops; 223 wdd->min_timeout = DA9063_WDT_MIN_TIMEOUT; 224 wdd->max_timeout = DA9063_WDT_MAX_TIMEOUT; 225 wdd->min_hw_heartbeat_ms = DA9063_RESET_PROTECTION_MS; 226 wdd->parent = dev; 227 wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS; 228 229 watchdog_set_restart_priority(wdd, 128); 230 watchdog_set_drvdata(wdd, da9063); 231 232 wdd->timeout = DA9063_WDG_TIMEOUT; 233 234 /* Use pre-configured timeout if watchdog is already running. */ 235 timeout = da9063_wdt_read_timeout(da9063); 236 if (timeout) 237 wdd->timeout = timeout; 238 239 /* Set timeout, maybe override it with DT value, scale it */ 240 watchdog_init_timeout(wdd, 0, dev); 241 da9063_wdt_set_timeout(wdd, wdd->timeout); 242 243 /* Update timeout if the watchdog is already running. */ 244 if (timeout) { 245 da9063_wdt_update_timeout(da9063, wdd->timeout); 246 set_bit(WDOG_HW_RUNNING, &wdd->status); 247 } 248 249 return devm_watchdog_register_device(dev, wdd); 250 } 251 252 static struct platform_driver da9063_wdt_driver = { 253 .probe = da9063_wdt_probe, 254 .driver = { 255 .name = DA9063_DRVNAME_WATCHDOG, 256 }, 257 }; 258 module_platform_driver(da9063_wdt_driver); 259 260 MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>"); 261 MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063"); 262 MODULE_LICENSE("GPL"); 263 MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG); 264