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 struct kref kref; 39 }; 40 41 static const struct { 42 u8 reg_val; 43 int user_time; /* In seconds */ 44 } da9055_wdt_maps[] = { 45 { 0, 0 }, 46 { 1, 2 }, 47 { 2, 4 }, 48 { 3, 8 }, 49 { 4, 16 }, 50 { 5, 32 }, 51 { 5, 33 }, /* Actual time 32.768s so included both 32s and 33s */ 52 { 6, 65 }, 53 { 6, 66 }, /* Actual time 65.536s so include both, 65s and 66s */ 54 { 7, 131 }, 55 }; 56 57 static int da9055_wdt_set_timeout(struct watchdog_device *wdt_dev, 58 unsigned int timeout) 59 { 60 struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); 61 struct da9055 *da9055 = driver_data->da9055; 62 int ret, i; 63 64 for (i = 0; i < ARRAY_SIZE(da9055_wdt_maps); i++) 65 if (da9055_wdt_maps[i].user_time == timeout) 66 break; 67 68 if (i == ARRAY_SIZE(da9055_wdt_maps)) 69 ret = -EINVAL; 70 else 71 ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B, 72 DA9055_TWDSCALE_MASK, 73 da9055_wdt_maps[i].reg_val << 74 DA9055_TWDSCALE_SHIFT); 75 if (ret < 0) { 76 dev_err(da9055->dev, 77 "Failed to update timescale bit, %d\n", ret); 78 return ret; 79 } 80 81 wdt_dev->timeout = timeout; 82 83 return 0; 84 } 85 86 static int da9055_wdt_ping(struct watchdog_device *wdt_dev) 87 { 88 struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); 89 struct da9055 *da9055 = driver_data->da9055; 90 91 /* 92 * We have a minimum time for watchdog window called TWDMIN. A write 93 * to the watchdog before this elapsed time will cause an error. 94 */ 95 mdelay(DA9055_TWDMIN); 96 97 /* Reset the watchdog timer */ 98 return da9055_reg_update(da9055, DA9055_REG_CONTROL_E, 99 DA9055_WATCHDOG_MASK, 1); 100 } 101 102 static void da9055_wdt_release_resources(struct kref *r) 103 { 104 } 105 106 static void da9055_wdt_ref(struct watchdog_device *wdt_dev) 107 { 108 struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); 109 110 kref_get(&driver_data->kref); 111 } 112 113 static void da9055_wdt_unref(struct watchdog_device *wdt_dev) 114 { 115 struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); 116 117 kref_put(&driver_data->kref, da9055_wdt_release_resources); 118 } 119 120 static int da9055_wdt_start(struct watchdog_device *wdt_dev) 121 { 122 return da9055_wdt_set_timeout(wdt_dev, wdt_dev->timeout); 123 } 124 125 static int da9055_wdt_stop(struct watchdog_device *wdt_dev) 126 { 127 return da9055_wdt_set_timeout(wdt_dev, 0); 128 } 129 130 static struct watchdog_info da9055_wdt_info = { 131 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, 132 .identity = "DA9055 Watchdog", 133 }; 134 135 static const struct watchdog_ops da9055_wdt_ops = { 136 .owner = THIS_MODULE, 137 .start = da9055_wdt_start, 138 .stop = da9055_wdt_stop, 139 .ping = da9055_wdt_ping, 140 .set_timeout = da9055_wdt_set_timeout, 141 .ref = da9055_wdt_ref, 142 .unref = da9055_wdt_unref, 143 }; 144 145 static int da9055_wdt_probe(struct platform_device *pdev) 146 { 147 struct da9055 *da9055 = dev_get_drvdata(pdev->dev.parent); 148 struct da9055_wdt_data *driver_data; 149 struct watchdog_device *da9055_wdt; 150 int ret; 151 152 driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data), 153 GFP_KERNEL); 154 if (!driver_data) { 155 dev_err(da9055->dev, "Failed to allocate watchdog device\n"); 156 return -ENOMEM; 157 } 158 159 driver_data->da9055 = da9055; 160 161 da9055_wdt = &driver_data->wdt; 162 163 da9055_wdt->timeout = DA9055_DEF_TIMEOUT; 164 da9055_wdt->info = &da9055_wdt_info; 165 da9055_wdt->ops = &da9055_wdt_ops; 166 watchdog_set_nowayout(da9055_wdt, nowayout); 167 watchdog_set_drvdata(da9055_wdt, driver_data); 168 169 kref_init(&driver_data->kref); 170 171 ret = da9055_wdt_stop(da9055_wdt); 172 if (ret < 0) { 173 dev_err(&pdev->dev, "Failed to stop watchdog, %d\n", ret); 174 goto err; 175 } 176 177 platform_set_drvdata(pdev, driver_data); 178 179 ret = watchdog_register_device(&driver_data->wdt); 180 if (ret != 0) 181 dev_err(da9055->dev, "watchdog_register_device() failed: %d\n", 182 ret); 183 184 err: 185 return ret; 186 } 187 188 static int da9055_wdt_remove(struct platform_device *pdev) 189 { 190 struct da9055_wdt_data *driver_data = platform_get_drvdata(pdev); 191 192 watchdog_unregister_device(&driver_data->wdt); 193 kref_put(&driver_data->kref, da9055_wdt_release_resources); 194 195 return 0; 196 } 197 198 static struct platform_driver da9055_wdt_driver = { 199 .probe = da9055_wdt_probe, 200 .remove = da9055_wdt_remove, 201 .driver = { 202 .name = "da9055-watchdog", 203 }, 204 }; 205 206 module_platform_driver(da9055_wdt_driver); 207 208 MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>"); 209 MODULE_DESCRIPTION("DA9055 watchdog"); 210 MODULE_LICENSE("GPL"); 211 MODULE_ALIAS("platform:da9055-watchdog"); 212