1 // SPDX-License-Identifier: GPL-2.0
3 * Watchdog driver for the MEN z069 IP-Core
5 * Copyright (C) 2018 Johannes Thumshirn <jth@kernel.org>
8 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/watchdog.h>
14 struct watchdog_device wdt;
19 #define MEN_Z069_WTR 0x10
20 #define MEN_Z069_WTR_WDEN BIT(15)
21 #define MEN_Z069_WTR_WDET_MASK 0x7fff
22 #define MEN_Z069_WVR 0x14
24 #define MEN_Z069_TIMER_FREQ 500 /* 500 Hz */
25 #define MEN_Z069_WDT_COUNTER_MIN 1
26 #define MEN_Z069_WDT_COUNTER_MAX 0x7fff
27 #define MEN_Z069_DEFAULT_TIMEOUT 30
29 static bool nowayout = WATCHDOG_NOWAYOUT;
30 module_param(nowayout, bool, 0);
31 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
32 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
34 static int men_z069_wdt_start(struct watchdog_device *wdt)
36 struct men_z069_drv *drv = watchdog_get_drvdata(wdt);
39 val = readw(drv->base + MEN_Z069_WTR);
40 val |= MEN_Z069_WTR_WDEN;
41 writew(val, drv->base + MEN_Z069_WTR);
46 static int men_z069_wdt_stop(struct watchdog_device *wdt)
48 struct men_z069_drv *drv = watchdog_get_drvdata(wdt);
51 val = readw(drv->base + MEN_Z069_WTR);
52 val &= ~MEN_Z069_WTR_WDEN;
53 writew(val, drv->base + MEN_Z069_WTR);
58 static int men_z069_wdt_ping(struct watchdog_device *wdt)
60 struct men_z069_drv *drv = watchdog_get_drvdata(wdt);
63 /* The watchdog trigger value toggles between 0x5555 and 0xaaaa */
64 val = readw(drv->base + MEN_Z069_WVR);
66 writew(val, drv->base + MEN_Z069_WVR);
71 static int men_z069_wdt_set_timeout(struct watchdog_device *wdt,
74 struct men_z069_drv *drv = watchdog_get_drvdata(wdt);
77 wdt->timeout = timeout;
78 val = timeout * MEN_Z069_TIMER_FREQ;
80 reg = readw(drv->base + MEN_Z069_WVR);
81 ena = reg & MEN_Z069_WTR_WDEN;
83 writew(reg, drv->base + MEN_Z069_WTR);
88 static const struct watchdog_info men_z069_info = {
89 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
90 .identity = "MEN z069 Watchdog",
93 static const struct watchdog_ops men_z069_ops = {
95 .start = men_z069_wdt_start,
96 .stop = men_z069_wdt_stop,
97 .ping = men_z069_wdt_ping,
98 .set_timeout = men_z069_wdt_set_timeout,
101 static struct watchdog_device men_z069_wdt = {
102 .info = &men_z069_info,
103 .ops = &men_z069_ops,
104 .timeout = MEN_Z069_DEFAULT_TIMEOUT,
106 .max_timeout = MEN_Z069_WDT_COUNTER_MAX / MEN_Z069_TIMER_FREQ,
109 static int men_z069_probe(struct mcb_device *dev,
110 const struct mcb_device_id *id)
112 struct men_z069_drv *drv;
113 struct resource *mem;
115 drv = devm_kzalloc(&dev->dev, sizeof(struct men_z069_drv), GFP_KERNEL);
119 mem = mcb_request_mem(dev, "z069-wdt");
123 drv->base = devm_ioremap(&dev->dev, mem->start, resource_size(mem));
124 if (drv->base == NULL)
129 drv->wdt = men_z069_wdt;
130 watchdog_init_timeout(&drv->wdt, 0, &dev->dev);
131 watchdog_set_nowayout(&drv->wdt, nowayout);
132 watchdog_set_drvdata(&drv->wdt, drv);
133 drv->wdt.parent = &dev->dev;
134 mcb_set_drvdata(dev, drv);
136 return watchdog_register_device(&men_z069_wdt);
139 mcb_release_mem(mem);
143 static void men_z069_remove(struct mcb_device *dev)
145 struct men_z069_drv *drv = mcb_get_drvdata(dev);
147 watchdog_unregister_device(&drv->wdt);
148 mcb_release_mem(drv->mem);
151 static const struct mcb_device_id men_z069_ids[] = {
155 MODULE_DEVICE_TABLE(mcb, men_z069_ids);
157 static struct mcb_driver men_z069_driver = {
160 .owner = THIS_MODULE,
162 .probe = men_z069_probe,
163 .remove = men_z069_remove,
164 .id_table = men_z069_ids,
166 module_mcb_driver(men_z069_driver);
168 MODULE_AUTHOR("Johannes Thumshirn <jth@kernel.org>");
169 MODULE_LICENSE("GPL v2");
170 MODULE_ALIAS("mcb:16z069");
171 MODULE_IMPORT_NS(MCB);