1 /* 2 * System monitoring driver for DA9055 PMICs. 3 * 4 * Copyright(c) 2012 Dialog Semiconductor Ltd. 5 * 6 * Author: David Dajun Chen <dchen@diasemi.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2 of the License, or 11 * (at your option) any later version. 12 * 13 */ 14 15 #include <linux/module.h> 16 #include <linux/types.h> 17 #include <linux/kernel.h> 18 #include <linux/slab.h> 19 #include <linux/platform_device.h> 20 #include <linux/watchdog.h> 21 #include <linux/delay.h> 22 23 #include <linux/mfd/da9055/core.h> 24 #include <linux/mfd/da9055/reg.h> 25 26 static bool nowayout = WATCHDOG_NOWAYOUT; 27 module_param(nowayout, bool, 0); 28 MODULE_PARM_DESC(nowayout, 29 "Watchdog cannot be stopped once started (default=" 30 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 31 32 #define DA9055_DEF_TIMEOUT 4 33 #define DA9055_TWDMIN 256 34 35 struct da9055_wdt_data { 36 struct watchdog_device wdt; 37 struct da9055 *da9055; 38 }; 39 40 static const struct { 41 u8 reg_val; 42 int user_time; /* In seconds */ 43 } da9055_wdt_maps[] = { 44 { 0, 0 }, 45 { 1, 2 }, 46 { 2, 4 }, 47 { 3, 8 }, 48 { 4, 16 }, 49 { 5, 32 }, 50 { 5, 33 }, /* Actual time 32.768s so included both 32s and 33s */ 51 { 6, 65 }, 52 { 6, 66 }, /* Actual time 65.536s so include both, 65s and 66s */ 53 { 7, 131 }, 54 }; 55 56 static int da9055_wdt_set_timeout(struct watchdog_device *wdt_dev, 57 unsigned int timeout) 58 { 59 struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); 60 struct da9055 *da9055 = driver_data->da9055; 61 int ret, i; 62 63 for (i = 0; i < ARRAY_SIZE(da9055_wdt_maps); i++) 64 if (da9055_wdt_maps[i].user_time == timeout) 65 break; 66 67 if (i == ARRAY_SIZE(da9055_wdt_maps)) 68 ret = -EINVAL; 69 else 70 ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B, 71 DA9055_TWDSCALE_MASK, 72 da9055_wdt_maps[i].reg_val << 73 DA9055_TWDSCALE_SHIFT); 74 if (ret < 0) { 75 dev_err(da9055->dev, 76 "Failed to update timescale bit, %d\n", ret); 77 return ret; 78 } 79 80 wdt_dev->timeout = timeout; 81 82 return 0; 83 } 84 85 static int da9055_wdt_ping(struct watchdog_device *wdt_dev) 86 { 87 struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); 88 struct da9055 *da9055 = driver_data->da9055; 89 90 /* 91 * We have a minimum time for watchdog window called TWDMIN. A write 92 * to the watchdog before this elapsed time will cause an error. 93 */ 94 mdelay(DA9055_TWDMIN); 95 96 /* Reset the watchdog timer */ 97 return da9055_reg_update(da9055, DA9055_REG_CONTROL_E, 98 DA9055_WATCHDOG_MASK, 1); 99 } 100 101 static int da9055_wdt_start(struct watchdog_device *wdt_dev) 102 { 103 return da9055_wdt_set_timeout(wdt_dev, wdt_dev->timeout); 104 } 105 106 static int da9055_wdt_stop(struct watchdog_device *wdt_dev) 107 { 108 return da9055_wdt_set_timeout(wdt_dev, 0); 109 } 110 111 static struct watchdog_info da9055_wdt_info = { 112 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, 113 .identity = "DA9055 Watchdog", 114 }; 115 116 static const struct watchdog_ops da9055_wdt_ops = { 117 .owner = THIS_MODULE, 118 .start = da9055_wdt_start, 119 .stop = da9055_wdt_stop, 120 .ping = da9055_wdt_ping, 121 .set_timeout = da9055_wdt_set_timeout, 122 }; 123 124 static int da9055_wdt_probe(struct platform_device *pdev) 125 { 126 struct da9055 *da9055 = dev_get_drvdata(pdev->dev.parent); 127 struct da9055_wdt_data *driver_data; 128 struct watchdog_device *da9055_wdt; 129 int ret; 130 131 driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data), 132 GFP_KERNEL); 133 if (!driver_data) 134 return -ENOMEM; 135 136 driver_data->da9055 = da9055; 137 138 da9055_wdt = &driver_data->wdt; 139 140 da9055_wdt->timeout = DA9055_DEF_TIMEOUT; 141 da9055_wdt->info = &da9055_wdt_info; 142 da9055_wdt->ops = &da9055_wdt_ops; 143 da9055_wdt->parent = &pdev->dev; 144 watchdog_set_nowayout(da9055_wdt, nowayout); 145 watchdog_set_drvdata(da9055_wdt, driver_data); 146 147 ret = da9055_wdt_stop(da9055_wdt); 148 if (ret < 0) { 149 dev_err(&pdev->dev, "Failed to stop watchdog, %d\n", ret); 150 goto err; 151 } 152 153 platform_set_drvdata(pdev, driver_data); 154 155 ret = watchdog_register_device(&driver_data->wdt); 156 if (ret != 0) 157 dev_err(da9055->dev, "watchdog_register_device() failed: %d\n", 158 ret); 159 160 err: 161 return ret; 162 } 163 164 static int da9055_wdt_remove(struct platform_device *pdev) 165 { 166 struct da9055_wdt_data *driver_data = platform_get_drvdata(pdev); 167 168 watchdog_unregister_device(&driver_data->wdt); 169 170 return 0; 171 } 172 173 static struct platform_driver da9055_wdt_driver = { 174 .probe = da9055_wdt_probe, 175 .remove = da9055_wdt_remove, 176 .driver = { 177 .name = "da9055-watchdog", 178 }, 179 }; 180 181 module_platform_driver(da9055_wdt_driver); 182 183 MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>"); 184 MODULE_DESCRIPTION("DA9055 watchdog"); 185 MODULE_LICENSE("GPL"); 186 MODULE_ALIAS("platform:da9055-watchdog"); 187