treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
[sfrench/cifs-2.6.git] / drivers / watchdog / nic7018_wdt.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2016 National Instruments Corp.
4  */
5
6 #include <linux/acpi.h>
7 #include <linux/bitops.h>
8 #include <linux/device.h>
9 #include <linux/io.h>
10 #include <linux/module.h>
11 #include <linux/platform_device.h>
12 #include <linux/watchdog.h>
13
14 #define LOCK                    0xA5
15 #define UNLOCK                  0x5A
16
17 #define WDT_CTRL_RESET_EN       BIT(7)
18 #define WDT_RELOAD_PORT_EN      BIT(7)
19
20 #define WDT_CTRL                1
21 #define WDT_RELOAD_CTRL         2
22 #define WDT_PRESET_PRESCALE     4
23 #define WDT_REG_LOCK            5
24 #define WDT_COUNT               6
25 #define WDT_RELOAD_PORT         7
26
27 #define WDT_MIN_TIMEOUT         1
28 #define WDT_MAX_TIMEOUT         464
29 #define WDT_DEFAULT_TIMEOUT     80
30
31 #define WDT_MAX_COUNTER         15
32
33 static unsigned int timeout;
34 module_param(timeout, uint, 0);
35 MODULE_PARM_DESC(timeout,
36                  "Watchdog timeout in seconds. (default="
37                  __MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");
38
39 static bool nowayout = WATCHDOG_NOWAYOUT;
40 module_param(nowayout, bool, 0);
41 MODULE_PARM_DESC(nowayout,
42                  "Watchdog cannot be stopped once started. (default="
43                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
44
45 struct nic7018_wdt {
46         u16 io_base;
47         u32 period;
48         struct watchdog_device wdd;
49 };
50
51 struct nic7018_config {
52         u32 period;
53         u8 divider;
54 };
55
56 static const struct nic7018_config nic7018_configs[] = {
57         {  2, 4 },
58         { 32, 5 },
59 };
60
61 static inline u32 nic7018_timeout(u32 period, u8 counter)
62 {
63         return period * counter - period / 2;
64 }
65
66 static const struct nic7018_config *nic7018_get_config(u32 timeout,
67                                                        u8 *counter)
68 {
69         const struct nic7018_config *config;
70         u8 count;
71
72         if (timeout < 30 && timeout != 16) {
73                 config = &nic7018_configs[0];
74                 count = timeout / 2 + 1;
75         } else {
76                 config = &nic7018_configs[1];
77                 count = DIV_ROUND_UP(timeout + 16, 32);
78
79                 if (count > WDT_MAX_COUNTER)
80                         count = WDT_MAX_COUNTER;
81         }
82         *counter = count;
83         return config;
84 }
85
86 static int nic7018_set_timeout(struct watchdog_device *wdd,
87                                unsigned int timeout)
88 {
89         struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
90         const struct nic7018_config *config;
91         u8 counter;
92
93         config = nic7018_get_config(timeout, &counter);
94
95         outb(counter << 4 | config->divider,
96              wdt->io_base + WDT_PRESET_PRESCALE);
97
98         wdd->timeout = nic7018_timeout(config->period, counter);
99         wdt->period = config->period;
100
101         return 0;
102 }
103
104 static int nic7018_start(struct watchdog_device *wdd)
105 {
106         struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
107         u8 control;
108
109         nic7018_set_timeout(wdd, wdd->timeout);
110
111         control = inb(wdt->io_base + WDT_RELOAD_CTRL);
112         outb(control | WDT_RELOAD_PORT_EN, wdt->io_base + WDT_RELOAD_CTRL);
113
114         outb(1, wdt->io_base + WDT_RELOAD_PORT);
115
116         control = inb(wdt->io_base + WDT_CTRL);
117         outb(control | WDT_CTRL_RESET_EN, wdt->io_base + WDT_CTRL);
118
119         return 0;
120 }
121
122 static int nic7018_stop(struct watchdog_device *wdd)
123 {
124         struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
125
126         outb(0, wdt->io_base + WDT_CTRL);
127         outb(0, wdt->io_base + WDT_RELOAD_CTRL);
128         outb(0xF0, wdt->io_base + WDT_PRESET_PRESCALE);
129
130         return 0;
131 }
132
133 static int nic7018_ping(struct watchdog_device *wdd)
134 {
135         struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
136
137         outb(1, wdt->io_base + WDT_RELOAD_PORT);
138
139         return 0;
140 }
141
142 static unsigned int nic7018_get_timeleft(struct watchdog_device *wdd)
143 {
144         struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
145         u8 count;
146
147         count = inb(wdt->io_base + WDT_COUNT) & 0xF;
148         if (!count)
149                 return 0;
150
151         return nic7018_timeout(wdt->period, count);
152 }
153
154 static const struct watchdog_info nic7018_wdd_info = {
155         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
156         .identity = "NIC7018 Watchdog",
157 };
158
159 static const struct watchdog_ops nic7018_wdd_ops = {
160         .owner = THIS_MODULE,
161         .start = nic7018_start,
162         .stop = nic7018_stop,
163         .ping = nic7018_ping,
164         .set_timeout = nic7018_set_timeout,
165         .get_timeleft = nic7018_get_timeleft,
166 };
167
168 static int nic7018_probe(struct platform_device *pdev)
169 {
170         struct device *dev = &pdev->dev;
171         struct watchdog_device *wdd;
172         struct nic7018_wdt *wdt;
173         struct resource *io_rc;
174         int ret;
175
176         wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
177         if (!wdt)
178                 return -ENOMEM;
179
180         platform_set_drvdata(pdev, wdt);
181
182         io_rc = platform_get_resource(pdev, IORESOURCE_IO, 0);
183         if (!io_rc) {
184                 dev_err(dev, "missing IO resources\n");
185                 return -EINVAL;
186         }
187
188         if (!devm_request_region(dev, io_rc->start, resource_size(io_rc),
189                                  KBUILD_MODNAME)) {
190                 dev_err(dev, "failed to get IO region\n");
191                 return -EBUSY;
192         }
193
194         wdt->io_base = io_rc->start;
195         wdd = &wdt->wdd;
196         wdd->info = &nic7018_wdd_info;
197         wdd->ops = &nic7018_wdd_ops;
198         wdd->min_timeout = WDT_MIN_TIMEOUT;
199         wdd->max_timeout = WDT_MAX_TIMEOUT;
200         wdd->timeout = WDT_DEFAULT_TIMEOUT;
201         wdd->parent = dev;
202
203         watchdog_set_drvdata(wdd, wdt);
204         watchdog_set_nowayout(wdd, nowayout);
205         watchdog_init_timeout(wdd, timeout, dev);
206
207         /* Unlock WDT register */
208         outb(UNLOCK, wdt->io_base + WDT_REG_LOCK);
209
210         ret = watchdog_register_device(wdd);
211         if (ret) {
212                 outb(LOCK, wdt->io_base + WDT_REG_LOCK);
213                 dev_err(dev, "failed to register watchdog\n");
214                 return ret;
215         }
216
217         dev_dbg(dev, "io_base=0x%04X, timeout=%d, nowayout=%d\n",
218                 wdt->io_base, timeout, nowayout);
219         return 0;
220 }
221
222 static int nic7018_remove(struct platform_device *pdev)
223 {
224         struct nic7018_wdt *wdt = platform_get_drvdata(pdev);
225
226         watchdog_unregister_device(&wdt->wdd);
227
228         /* Lock WDT register */
229         outb(LOCK, wdt->io_base + WDT_REG_LOCK);
230
231         return 0;
232 }
233
234 static const struct acpi_device_id nic7018_device_ids[] = {
235         {"NIC7018", 0},
236         {"", 0},
237 };
238 MODULE_DEVICE_TABLE(acpi, nic7018_device_ids);
239
240 static struct platform_driver watchdog_driver = {
241         .probe = nic7018_probe,
242         .remove = nic7018_remove,
243         .driver = {
244                 .name = KBUILD_MODNAME,
245                 .acpi_match_table = ACPI_PTR(nic7018_device_ids),
246         },
247 };
248
249 module_platform_driver(watchdog_driver);
250
251 MODULE_DESCRIPTION("National Instruments NIC7018 Watchdog driver");
252 MODULE_AUTHOR("Hui Chun Ong <hui.chun.ong@ni.com>");
253 MODULE_LICENSE("GPL");