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 * Return 0 if watchdog is disabled, else non zero. 50 */ 51 static unsigned int da9063_wdt_is_running(struct da9063 *da9063) 52 { 53 unsigned int val; 54 55 regmap_read(da9063->regmap, DA9063_REG_CONTROL_D, &val); 56 57 return val & DA9063_TWDSCALE_MASK; 58 } 59 60 static int da9063_wdt_disable_timer(struct da9063 *da9063) 61 { 62 return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D, 63 DA9063_TWDSCALE_MASK, 64 DA9063_TWDSCALE_DISABLE); 65 } 66 67 static int 68 da9063_wdt_update_timeout(struct da9063 *da9063, unsigned int timeout) 69 { 70 unsigned int regval; 71 int ret; 72 73 /* 74 * The watchdog triggers a reboot if a timeout value is already 75 * programmed because the timeout value combines two functions 76 * in one: indicating the counter limit and starting the watchdog. 77 * The watchdog must be disabled to be able to change the timeout 78 * value if the watchdog is already running. Then we can set the 79 * new timeout value which enables the watchdog again. 80 */ 81 ret = da9063_wdt_disable_timer(da9063); 82 if (ret) 83 return ret; 84 85 usleep_range(150, 300); 86 regval = da9063_wdt_timeout_to_sel(timeout); 87 88 return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D, 89 DA9063_TWDSCALE_MASK, regval); 90 } 91 92 static int da9063_wdt_start(struct watchdog_device *wdd) 93 { 94 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 95 int ret; 96 97 ret = da9063_wdt_update_timeout(da9063, wdd->timeout); 98 if (ret) 99 dev_err(da9063->dev, "Watchdog failed to start (err = %d)\n", 100 ret); 101 102 return ret; 103 } 104 105 static int da9063_wdt_stop(struct watchdog_device *wdd) 106 { 107 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 108 int ret; 109 110 ret = da9063_wdt_disable_timer(da9063); 111 if (ret) 112 dev_alert(da9063->dev, "Watchdog failed to stop (err = %d)\n", 113 ret); 114 115 return ret; 116 } 117 118 static int da9063_wdt_ping(struct watchdog_device *wdd) 119 { 120 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 121 int ret; 122 123 ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F, 124 DA9063_WATCHDOG); 125 if (ret) 126 dev_alert(da9063->dev, "Failed to ping the watchdog (err = %d)\n", 127 ret); 128 129 return ret; 130 } 131 132 static int da9063_wdt_set_timeout(struct watchdog_device *wdd, 133 unsigned int timeout) 134 { 135 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 136 int ret = 0; 137 138 /* 139 * There are two cases when a set_timeout() will be called: 140 * 1. The watchdog is off and someone wants to set the timeout for the 141 * further use. 142 * 2. The watchdog is already running and a new timeout value should be 143 * set. 144 * 145 * The watchdog can't store a timeout value not equal zero without 146 * enabling the watchdog, so the timeout must be buffered by the driver. 147 */ 148 if (watchdog_active(wdd)) 149 ret = da9063_wdt_update_timeout(da9063, timeout); 150 151 if (ret) 152 dev_err(da9063->dev, "Failed to set watchdog timeout (err = %d)\n", 153 ret); 154 else 155 wdd->timeout = wdt_timeout[da9063_wdt_timeout_to_sel(timeout)]; 156 157 return ret; 158 } 159 160 static int da9063_wdt_restart(struct watchdog_device *wdd, unsigned long action, 161 void *data) 162 { 163 struct da9063 *da9063 = watchdog_get_drvdata(wdd); 164 int ret; 165 166 ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F, 167 DA9063_SHUTDOWN); 168 if (ret) 169 dev_alert(da9063->dev, "Failed to shutdown (err = %d)\n", 170 ret); 171 172 return ret; 173 } 174 175 static const struct watchdog_info da9063_watchdog_info = { 176 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, 177 .identity = "DA9063 Watchdog", 178 }; 179 180 static const struct watchdog_ops da9063_watchdog_ops = { 181 .owner = THIS_MODULE, 182 .start = da9063_wdt_start, 183 .stop = da9063_wdt_stop, 184 .ping = da9063_wdt_ping, 185 .set_timeout = da9063_wdt_set_timeout, 186 .restart = da9063_wdt_restart, 187 }; 188 189 static int da9063_wdt_probe(struct platform_device *pdev) 190 { 191 struct device *dev = &pdev->dev; 192 struct da9063 *da9063; 193 struct watchdog_device *wdd; 194 195 if (!dev->parent) 196 return -EINVAL; 197 198 da9063 = dev_get_drvdata(dev->parent); 199 if (!da9063) 200 return -EINVAL; 201 202 wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL); 203 if (!wdd) 204 return -ENOMEM; 205 206 wdd->info = &da9063_watchdog_info; 207 wdd->ops = &da9063_watchdog_ops; 208 wdd->min_timeout = DA9063_WDT_MIN_TIMEOUT; 209 wdd->max_timeout = DA9063_WDT_MAX_TIMEOUT; 210 wdd->min_hw_heartbeat_ms = DA9063_RESET_PROTECTION_MS; 211 wdd->parent = dev; 212 wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS; 213 214 watchdog_set_restart_priority(wdd, 128); 215 watchdog_set_drvdata(wdd, da9063); 216 217 /* Set default timeout, maybe override it with DT value, scale it */ 218 wdd->timeout = DA9063_WDG_TIMEOUT; 219 watchdog_init_timeout(wdd, 0, dev); 220 da9063_wdt_set_timeout(wdd, wdd->timeout); 221 222 /* Change the timeout to the default value if the watchdog is running */ 223 if (da9063_wdt_is_running(da9063)) { 224 da9063_wdt_update_timeout(da9063, wdd->timeout); 225 set_bit(WDOG_HW_RUNNING, &wdd->status); 226 } 227 228 return devm_watchdog_register_device(dev, wdd); 229 } 230 231 static struct platform_driver da9063_wdt_driver = { 232 .probe = da9063_wdt_probe, 233 .driver = { 234 .name = DA9063_DRVNAME_WATCHDOG, 235 }, 236 }; 237 module_platform_driver(da9063_wdt_driver); 238 239 MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>"); 240 MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063"); 241 MODULE_LICENSE("GPL"); 242 MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG); 243