1 /* 2 * System monitoring driver for DA9052 PMICs. 3 * 4 * Copyright(c) 2012 Dialog Semiconductor Ltd. 5 * 6 * Author: Anthony Olech <Anthony.Olech@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/delay.h> 17 #include <linux/uaccess.h> 18 #include <linux/platform_device.h> 19 #include <linux/time.h> 20 #include <linux/watchdog.h> 21 #include <linux/types.h> 22 #include <linux/kernel.h> 23 #include <linux/jiffies.h> 24 25 #include <linux/mfd/da9052/reg.h> 26 #include <linux/mfd/da9052/da9052.h> 27 28 #define DA9052_DEF_TIMEOUT 4 29 #define DA9052_TWDMIN 256 30 31 struct da9052_wdt_data { 32 struct watchdog_device wdt; 33 struct da9052 *da9052; 34 struct kref kref; 35 unsigned long jpast; 36 }; 37 38 static const struct { 39 u8 reg_val; 40 int time; /* Seconds */ 41 } da9052_wdt_maps[] = { 42 { 1, 2 }, 43 { 2, 4 }, 44 { 3, 8 }, 45 { 4, 16 }, 46 { 5, 32 }, 47 { 5, 33 }, /* Actual time 32.768s so included both 32s and 33s */ 48 { 6, 65 }, 49 { 6, 66 }, /* Actual time 65.536s so include both, 65s and 66s */ 50 { 7, 131 }, 51 }; 52 53 54 static void da9052_wdt_release_resources(struct kref *r) 55 { 56 } 57 58 static int da9052_wdt_set_timeout(struct watchdog_device *wdt_dev, 59 unsigned int timeout) 60 { 61 struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); 62 struct da9052 *da9052 = driver_data->da9052; 63 int ret, i; 64 65 /* 66 * Disable the Watchdog timer before setting 67 * new time out. 68 */ 69 ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG, 70 DA9052_CONTROLD_TWDSCALE, 0); 71 if (ret < 0) { 72 dev_err(da9052->dev, "Failed to disable watchdog bit, %d\n", 73 ret); 74 return ret; 75 } 76 if (timeout) { 77 /* 78 * To change the timeout, da9052 needs to 79 * be disabled for at least 150 us. 80 */ 81 udelay(150); 82 83 /* Set the desired timeout */ 84 for (i = 0; i < ARRAY_SIZE(da9052_wdt_maps); i++) 85 if (da9052_wdt_maps[i].time == timeout) 86 break; 87 88 if (i == ARRAY_SIZE(da9052_wdt_maps)) 89 ret = -EINVAL; 90 else 91 ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG, 92 DA9052_CONTROLD_TWDSCALE, 93 da9052_wdt_maps[i].reg_val); 94 if (ret < 0) { 95 dev_err(da9052->dev, 96 "Failed to update timescale bit, %d\n", ret); 97 return ret; 98 } 99 100 wdt_dev->timeout = timeout; 101 driver_data->jpast = jiffies; 102 } 103 104 return 0; 105 } 106 107 static void da9052_wdt_ref(struct watchdog_device *wdt_dev) 108 { 109 struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); 110 111 kref_get(&driver_data->kref); 112 } 113 114 static void da9052_wdt_unref(struct watchdog_device *wdt_dev) 115 { 116 struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); 117 118 kref_put(&driver_data->kref, da9052_wdt_release_resources); 119 } 120 121 static int da9052_wdt_start(struct watchdog_device *wdt_dev) 122 { 123 return da9052_wdt_set_timeout(wdt_dev, wdt_dev->timeout); 124 } 125 126 static int da9052_wdt_stop(struct watchdog_device *wdt_dev) 127 { 128 return da9052_wdt_set_timeout(wdt_dev, 0); 129 } 130 131 static int da9052_wdt_ping(struct watchdog_device *wdt_dev) 132 { 133 struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); 134 struct da9052 *da9052 = driver_data->da9052; 135 unsigned long msec, jnow = jiffies; 136 int ret; 137 138 /* 139 * We have a minimum time for watchdog window called TWDMIN. A write 140 * to the watchdog before this elapsed time should cause an error. 141 */ 142 msec = (jnow - driver_data->jpast) * 1000/HZ; 143 if (msec < DA9052_TWDMIN) 144 mdelay(msec); 145 146 /* Reset the watchdog timer */ 147 ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG, 148 DA9052_CONTROLD_WATCHDOG, 1 << 7); 149 if (ret < 0) 150 goto err_strobe; 151 152 /* 153 * FIXME: Reset the watchdog core, in general PMIC 154 * is supposed to do this 155 */ 156 ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG, 157 DA9052_CONTROLD_WATCHDOG, 0 << 7); 158 err_strobe: 159 return ret; 160 } 161 162 static struct watchdog_info da9052_wdt_info = { 163 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, 164 .identity = "DA9052 Watchdog", 165 }; 166 167 static const struct watchdog_ops da9052_wdt_ops = { 168 .owner = THIS_MODULE, 169 .start = da9052_wdt_start, 170 .stop = da9052_wdt_stop, 171 .ping = da9052_wdt_ping, 172 .set_timeout = da9052_wdt_set_timeout, 173 .ref = da9052_wdt_ref, 174 .unref = da9052_wdt_unref, 175 }; 176 177 178 static int da9052_wdt_probe(struct platform_device *pdev) 179 { 180 struct da9052 *da9052 = dev_get_drvdata(pdev->dev.parent); 181 struct da9052_wdt_data *driver_data; 182 struct watchdog_device *da9052_wdt; 183 int ret; 184 185 driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data), 186 GFP_KERNEL); 187 if (!driver_data) { 188 ret = -ENOMEM; 189 goto err; 190 } 191 driver_data->da9052 = da9052; 192 193 da9052_wdt = &driver_data->wdt; 194 195 da9052_wdt->timeout = DA9052_DEF_TIMEOUT; 196 da9052_wdt->info = &da9052_wdt_info; 197 da9052_wdt->ops = &da9052_wdt_ops; 198 watchdog_set_drvdata(da9052_wdt, driver_data); 199 200 kref_init(&driver_data->kref); 201 202 ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG, 203 DA9052_CONTROLD_TWDSCALE, 0); 204 if (ret < 0) { 205 dev_err(&pdev->dev, "Failed to disable watchdog bits, %d\n", 206 ret); 207 goto err; 208 } 209 210 ret = watchdog_register_device(&driver_data->wdt); 211 if (ret != 0) { 212 dev_err(da9052->dev, "watchdog_register_device() failed: %d\n", 213 ret); 214 goto err; 215 } 216 217 platform_set_drvdata(pdev, driver_data); 218 err: 219 return ret; 220 } 221 222 static int da9052_wdt_remove(struct platform_device *pdev) 223 { 224 struct da9052_wdt_data *driver_data = platform_get_drvdata(pdev); 225 226 watchdog_unregister_device(&driver_data->wdt); 227 kref_put(&driver_data->kref, da9052_wdt_release_resources); 228 229 return 0; 230 } 231 232 static struct platform_driver da9052_wdt_driver = { 233 .probe = da9052_wdt_probe, 234 .remove = da9052_wdt_remove, 235 .driver = { 236 .name = "da9052-watchdog", 237 }, 238 }; 239 240 module_platform_driver(da9052_wdt_driver); 241 242 MODULE_AUTHOR("Anthony Olech <Anthony.Olech@diasemi.com>"); 243 MODULE_DESCRIPTION("DA9052 SM Device Driver"); 244 MODULE_LICENSE("GPL"); 245 MODULE_ALIAS("platform:da9052-watchdog"); 246