1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * System monitoring driver for DA9055 PMICs. 4 * 5 * Copyright(c) 2012 Dialog Semiconductor Ltd. 6 * 7 * Author: David Dajun Chen <dchen@diasemi.com> 8 * 9 */ 10 11 #include <linux/module.h> 12 #include <linux/types.h> 13 #include <linux/kernel.h> 14 #include <linux/slab.h> 15 #include <linux/platform_device.h> 16 #include <linux/watchdog.h> 17 #include <linux/delay.h> 18 19 #include <linux/mfd/da9055/core.h> 20 #include <linux/mfd/da9055/reg.h> 21 22 static bool nowayout = WATCHDOG_NOWAYOUT; 23 module_param(nowayout, bool, 0); 24 MODULE_PARM_DESC(nowayout, 25 "Watchdog cannot be stopped once started (default=" 26 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 27 28 #define DA9055_DEF_TIMEOUT 4 29 #define DA9055_TWDMIN 256 30 31 struct da9055_wdt_data { 32 struct watchdog_device wdt; 33 struct da9055 *da9055; 34 }; 35 36 static const struct { 37 u8 reg_val; 38 int user_time; /* In seconds */ 39 } da9055_wdt_maps[] = { 40 { 0, 0 }, 41 { 1, 2 }, 42 { 2, 4 }, 43 { 3, 8 }, 44 { 4, 16 }, 45 { 5, 32 }, 46 { 5, 33 }, /* Actual time 32.768s so included both 32s and 33s */ 47 { 6, 65 }, 48 { 6, 66 }, /* Actual time 65.536s so include both, 65s and 66s */ 49 { 7, 131 }, 50 }; 51 52 static int da9055_wdt_set_timeout(struct watchdog_device *wdt_dev, 53 unsigned int timeout) 54 { 55 struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); 56 struct da9055 *da9055 = driver_data->da9055; 57 int ret, i; 58 59 for (i = 0; i < ARRAY_SIZE(da9055_wdt_maps); i++) 60 if (da9055_wdt_maps[i].user_time == timeout) 61 break; 62 63 if (i == ARRAY_SIZE(da9055_wdt_maps)) 64 ret = -EINVAL; 65 else 66 ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B, 67 DA9055_TWDSCALE_MASK, 68 da9055_wdt_maps[i].reg_val << 69 DA9055_TWDSCALE_SHIFT); 70 if (ret < 0) { 71 dev_err(da9055->dev, 72 "Failed to update timescale bit, %d\n", ret); 73 return ret; 74 } 75 76 wdt_dev->timeout = timeout; 77 78 return 0; 79 } 80 81 static int da9055_wdt_ping(struct watchdog_device *wdt_dev) 82 { 83 struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); 84 struct da9055 *da9055 = driver_data->da9055; 85 86 /* 87 * We have a minimum time for watchdog window called TWDMIN. A write 88 * to the watchdog before this elapsed time will cause an error. 89 */ 90 mdelay(DA9055_TWDMIN); 91 92 /* Reset the watchdog timer */ 93 return da9055_reg_update(da9055, DA9055_REG_CONTROL_E, 94 DA9055_WATCHDOG_MASK, 1); 95 } 96 97 static int da9055_wdt_start(struct watchdog_device *wdt_dev) 98 { 99 return da9055_wdt_set_timeout(wdt_dev, wdt_dev->timeout); 100 } 101 102 static int da9055_wdt_stop(struct watchdog_device *wdt_dev) 103 { 104 return da9055_wdt_set_timeout(wdt_dev, 0); 105 } 106 107 static const struct watchdog_info da9055_wdt_info = { 108 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, 109 .identity = "DA9055 Watchdog", 110 }; 111 112 static const struct watchdog_ops da9055_wdt_ops = { 113 .owner = THIS_MODULE, 114 .start = da9055_wdt_start, 115 .stop = da9055_wdt_stop, 116 .ping = da9055_wdt_ping, 117 .set_timeout = da9055_wdt_set_timeout, 118 }; 119 120 static int da9055_wdt_probe(struct platform_device *pdev) 121 { 122 struct device *dev = &pdev->dev; 123 struct da9055 *da9055 = dev_get_drvdata(dev->parent); 124 struct da9055_wdt_data *driver_data; 125 struct watchdog_device *da9055_wdt; 126 int ret; 127 128 driver_data = devm_kzalloc(dev, sizeof(*driver_data), GFP_KERNEL); 129 if (!driver_data) 130 return -ENOMEM; 131 132 driver_data->da9055 = da9055; 133 134 da9055_wdt = &driver_data->wdt; 135 136 da9055_wdt->timeout = DA9055_DEF_TIMEOUT; 137 da9055_wdt->info = &da9055_wdt_info; 138 da9055_wdt->ops = &da9055_wdt_ops; 139 da9055_wdt->parent = dev; 140 watchdog_set_nowayout(da9055_wdt, nowayout); 141 watchdog_set_drvdata(da9055_wdt, driver_data); 142 143 ret = da9055_wdt_stop(da9055_wdt); 144 if (ret < 0) { 145 dev_err(dev, "Failed to stop watchdog, %d\n", ret); 146 return ret; 147 } 148 149 ret = devm_watchdog_register_device(dev, &driver_data->wdt); 150 if (ret != 0) 151 dev_err(da9055->dev, "watchdog_register_device() failed: %d\n", 152 ret); 153 154 return ret; 155 } 156 157 static struct platform_driver da9055_wdt_driver = { 158 .probe = da9055_wdt_probe, 159 .driver = { 160 .name = "da9055-watchdog", 161 }, 162 }; 163 164 module_platform_driver(da9055_wdt_driver); 165 166 MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>"); 167 MODULE_DESCRIPTION("DA9055 watchdog"); 168 MODULE_LICENSE("GPL"); 169 MODULE_ALIAS("platform:da9055-watchdog"); 170