1 /* 2 * Watchdog driver for Ricoh RN5T618 PMIC 3 * 4 * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com> 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * version 2 as published by the Free Software Foundation. 9 * 10 * You should have received a copy of the GNU General Public License 11 * along with this program. If not, see <http://www.gnu.org/licenses/>. 12 */ 13 14 #include <linux/device.h> 15 #include <linux/mfd/rn5t618.h> 16 #include <linux/module.h> 17 #include <linux/platform_device.h> 18 #include <linux/watchdog.h> 19 20 #define DRIVER_NAME "rn5t618-wdt" 21 22 static bool nowayout = WATCHDOG_NOWAYOUT; 23 static unsigned int timeout; 24 25 module_param(timeout, uint, 0); 26 MODULE_PARM_DESC(timeout, "Initial watchdog timeout in seconds"); 27 28 module_param(nowayout, bool, 0); 29 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" 30 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 31 32 struct rn5t618_wdt { 33 struct watchdog_device wdt_dev; 34 struct rn5t618 *rn5t618; 35 }; 36 37 /* 38 * This array encodes the values of WDOGTIM field for the supported 39 * watchdog expiration times. If the watchdog is not accessed before 40 * the timer expiration, the PMU generates an interrupt and if the CPU 41 * doesn't clear it within one second the system is restarted. 42 */ 43 static const struct { 44 u8 reg_val; 45 unsigned int time; 46 } rn5t618_wdt_map[] = { 47 { 0, 1 }, 48 { 1, 8 }, 49 { 2, 32 }, 50 { 3, 128 }, 51 }; 52 53 static int rn5t618_wdt_set_timeout(struct watchdog_device *wdt_dev, 54 unsigned int t) 55 { 56 struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev); 57 int ret, i; 58 59 for (i = 0; i < ARRAY_SIZE(rn5t618_wdt_map); i++) { 60 if (rn5t618_wdt_map[i].time + 1 >= t) 61 break; 62 } 63 64 if (i == ARRAY_SIZE(rn5t618_wdt_map)) 65 return -EINVAL; 66 67 ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG, 68 RN5T618_WATCHDOG_WDOGTIM_M, 69 rn5t618_wdt_map[i].reg_val); 70 if (!ret) 71 wdt_dev->timeout = rn5t618_wdt_map[i].time; 72 73 return ret; 74 } 75 76 static int rn5t618_wdt_start(struct watchdog_device *wdt_dev) 77 { 78 struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev); 79 int ret; 80 81 ret = rn5t618_wdt_set_timeout(wdt_dev, wdt_dev->timeout); 82 if (ret) 83 return ret; 84 85 /* enable repower-on */ 86 ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_REPCNT, 87 RN5T618_REPCNT_REPWRON, 88 RN5T618_REPCNT_REPWRON); 89 if (ret) 90 return ret; 91 92 /* enable watchdog */ 93 ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG, 94 RN5T618_WATCHDOG_WDOGEN, 95 RN5T618_WATCHDOG_WDOGEN); 96 if (ret) 97 return ret; 98 99 /* enable watchdog interrupt */ 100 return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_PWRIREN, 101 RN5T618_PWRIRQ_IR_WDOG, 102 RN5T618_PWRIRQ_IR_WDOG); 103 } 104 105 static int rn5t618_wdt_stop(struct watchdog_device *wdt_dev) 106 { 107 struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev); 108 109 return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG, 110 RN5T618_WATCHDOG_WDOGEN, 0); 111 } 112 113 static int rn5t618_wdt_ping(struct watchdog_device *wdt_dev) 114 { 115 struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev); 116 unsigned int val; 117 int ret; 118 119 /* The counter is restarted after a R/W access to watchdog register */ 120 ret = regmap_read(wdt->rn5t618->regmap, RN5T618_WATCHDOG, &val); 121 if (ret) 122 return ret; 123 124 ret = regmap_write(wdt->rn5t618->regmap, RN5T618_WATCHDOG, val); 125 if (ret) 126 return ret; 127 128 /* Clear pending watchdog interrupt */ 129 return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_PWRIRQ, 130 RN5T618_PWRIRQ_IR_WDOG, 0); 131 } 132 133 static const struct watchdog_info rn5t618_wdt_info = { 134 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | 135 WDIOF_KEEPALIVEPING, 136 .identity = DRIVER_NAME, 137 }; 138 139 static const struct watchdog_ops rn5t618_wdt_ops = { 140 .owner = THIS_MODULE, 141 .start = rn5t618_wdt_start, 142 .stop = rn5t618_wdt_stop, 143 .ping = rn5t618_wdt_ping, 144 .set_timeout = rn5t618_wdt_set_timeout, 145 }; 146 147 static int rn5t618_wdt_probe(struct platform_device *pdev) 148 { 149 struct rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent); 150 struct rn5t618_wdt *wdt; 151 int min_timeout, max_timeout; 152 153 wdt = devm_kzalloc(&pdev->dev, sizeof(struct rn5t618_wdt), GFP_KERNEL); 154 if (!wdt) 155 return -ENOMEM; 156 157 min_timeout = rn5t618_wdt_map[0].time; 158 max_timeout = rn5t618_wdt_map[ARRAY_SIZE(rn5t618_wdt_map) - 1].time; 159 160 wdt->rn5t618 = rn5t618; 161 wdt->wdt_dev.info = &rn5t618_wdt_info; 162 wdt->wdt_dev.ops = &rn5t618_wdt_ops; 163 wdt->wdt_dev.min_timeout = min_timeout; 164 wdt->wdt_dev.max_timeout = max_timeout; 165 wdt->wdt_dev.timeout = max_timeout; 166 wdt->wdt_dev.parent = &pdev->dev; 167 168 watchdog_set_drvdata(&wdt->wdt_dev, wdt); 169 watchdog_init_timeout(&wdt->wdt_dev, timeout, &pdev->dev); 170 watchdog_set_nowayout(&wdt->wdt_dev, nowayout); 171 172 platform_set_drvdata(pdev, wdt); 173 174 return watchdog_register_device(&wdt->wdt_dev); 175 } 176 177 static int rn5t618_wdt_remove(struct platform_device *pdev) 178 { 179 struct rn5t618_wdt *wdt = platform_get_drvdata(pdev); 180 181 watchdog_unregister_device(&wdt->wdt_dev); 182 183 return 0; 184 } 185 186 static struct platform_driver rn5t618_wdt_driver = { 187 .probe = rn5t618_wdt_probe, 188 .remove = rn5t618_wdt_remove, 189 .driver = { 190 .name = DRIVER_NAME, 191 }, 192 }; 193 194 module_platform_driver(rn5t618_wdt_driver); 195 196 MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>"); 197 MODULE_DESCRIPTION("RN5T618 watchdog driver"); 198 MODULE_LICENSE("GPL v2"); 199