1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Watchdog Timer Driver
4 * for ITE IT87xx Environment Control - Low Pin Count Input / Output
6 * (c) Copyright 2007 Oliver Schuster <olivers137@aol.com>
8 * Based on softdog.c by Alan Cox,
9 * 83977f_wdt.c by Jose Goncalves,
10 * it87.c by Chris Gauthron, Jean Delvare
12 * Data-sheets: Publicly available at the ITE website
13 * http://www.ite.com.tw/
15 * Support of the watchdog timers, which are available on
16 * IT8607, IT8620, IT8622, IT8625, IT8628, IT8655, IT8665, IT8686,
17 * IT8702, IT8712, IT8716, IT8718, IT8720, IT8721, IT8726, IT8728,
18 * IT8772, IT8783 and IT8784.
21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23 #include <linux/init.h>
25 #include <linux/kernel.h>
26 #include <linux/module.h>
27 #include <linux/moduleparam.h>
28 #include <linux/types.h>
29 #include <linux/watchdog.h>
31 #define WATCHDOG_NAME "IT87 WDT"
33 /* Defaults for Module Parameter */
34 #define DEFAULT_TIMEOUT 60
35 #define DEFAULT_TESTMODE 0
36 #define DEFAULT_NOWAYOUT WATCHDOG_NOWAYOUT
42 /* Logical device Numbers LDN */
45 /* Configuration Registers and Functions */
51 #define NO_DEV_ID 0xffff
52 #define IT8607_ID 0x8607
53 #define IT8620_ID 0x8620
54 #define IT8622_ID 0x8622
55 #define IT8625_ID 0x8625
56 #define IT8628_ID 0x8628
57 #define IT8655_ID 0x8655
58 #define IT8665_ID 0x8665
59 #define IT8686_ID 0x8686
60 #define IT8702_ID 0x8702
61 #define IT8705_ID 0x8705
62 #define IT8712_ID 0x8712
63 #define IT8716_ID 0x8716
64 #define IT8718_ID 0x8718
65 #define IT8720_ID 0x8720
66 #define IT8721_ID 0x8721
67 #define IT8726_ID 0x8726 /* the data sheet suggest wrongly 0x8716 */
68 #define IT8728_ID 0x8728
69 #define IT8772_ID 0x8772
70 #define IT8783_ID 0x8783
71 #define IT8784_ID 0x8784
72 #define IT8786_ID 0x8786
74 /* GPIO Configuration Registers LDN=0x07 */
77 #define WDTVALLSB 0x73
78 #define WDTVALMSB 0x74
80 /* GPIO Bits WDTCFG */
84 #define WDT_PWROK 0x10 /* not in it8721 */
85 #define WDT_INT_MASK 0x0f
87 static unsigned int max_units, chip_type;
89 static unsigned int timeout = DEFAULT_TIMEOUT;
90 static int testmode = DEFAULT_TESTMODE;
91 static bool nowayout = DEFAULT_NOWAYOUT;
93 module_param(timeout, int, 0);
94 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, default="
95 __MODULE_STRING(DEFAULT_TIMEOUT));
96 module_param(testmode, int, 0);
97 MODULE_PARM_DESC(testmode, "Watchdog test mode (1 = no reboot), default="
98 __MODULE_STRING(DEFAULT_TESTMODE));
99 module_param(nowayout, bool, 0);
100 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started, default="
101 __MODULE_STRING(WATCHDOG_NOWAYOUT));
105 static inline int superio_enter(void)
108 * Try to reserve REG and REG + 1 for exclusive access.
110 if (!request_muxed_region(REG, 2, WATCHDOG_NAME))
120 static inline void superio_exit(void)
124 release_region(REG, 2);
127 static inline void superio_select(int ldn)
133 static inline int superio_inb(int reg)
139 static inline void superio_outb(int val, int reg)
145 static inline int superio_inw(int reg)
155 /* Internal function, should be called after superio_select(GPIO) */
156 static void _wdt_update_timeout(unsigned int t)
158 unsigned char cfg = WDT_KRST;
168 if (chip_type != IT8721_ID)
171 superio_outb(cfg, WDTCFG);
172 superio_outb(t, WDTVALLSB);
174 superio_outb(t >> 8, WDTVALMSB);
177 static int wdt_update_timeout(unsigned int t)
181 ret = superio_enter();
185 superio_select(GPIO);
186 _wdt_update_timeout(t);
192 static int wdt_round_time(int t)
199 /* watchdog timer handling */
201 static int wdt_start(struct watchdog_device *wdd)
203 return wdt_update_timeout(wdd->timeout);
206 static int wdt_stop(struct watchdog_device *wdd)
208 return wdt_update_timeout(0);
212 * wdt_set_timeout - set a new timeout value with watchdog ioctl
213 * @t: timeout value in seconds
215 * The hardware device has a 8 or 16 bit watchdog timer (depends on
216 * chip version) that can be configured to count seconds or minutes.
218 * Used within WDIOC_SETTIMEOUT watchdog device ioctl.
221 static int wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
226 t = wdt_round_time(t);
230 if (watchdog_hw_running(wdd))
231 ret = wdt_update_timeout(t);
236 static const struct watchdog_info ident = {
237 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
238 .firmware_version = 1,
239 .identity = WATCHDOG_NAME,
242 static const struct watchdog_ops wdt_ops = {
243 .owner = THIS_MODULE,
246 .set_timeout = wdt_set_timeout,
249 static struct watchdog_device wdt_dev = {
255 static int __init it87_wdt_init(void)
260 rc = superio_enter();
264 chip_type = superio_inw(CHIPID);
265 chip_rev = superio_inb(CHIPREV) & 0x0f;
273 max_units = (chip_rev < 8) ? 255 : 65535;
298 pr_err("Unsupported Chip found, Chip %04x Revision %02x\n",
299 chip_type, chip_rev);
302 pr_err("no device\n");
305 pr_err("Unknown Chip found, Chip %04x Revision %04x\n",
306 chip_type, chip_rev);
310 rc = superio_enter();
314 superio_select(GPIO);
315 superio_outb(WDT_TOV1, WDTCFG);
316 superio_outb(0x00, WDTCTRL);
319 if (timeout < 1 || timeout > max_units * 60) {
320 timeout = DEFAULT_TIMEOUT;
321 pr_warn("Timeout value out of range, use default %d sec\n",
325 if (timeout > max_units)
326 timeout = wdt_round_time(timeout);
328 wdt_dev.timeout = timeout;
329 wdt_dev.max_timeout = max_units * 60;
331 watchdog_stop_on_reboot(&wdt_dev);
332 rc = watchdog_register_device(&wdt_dev);
334 pr_err("Cannot register watchdog device (err=%d)\n", rc);
338 pr_info("Chip IT%04x revision %d initialized. timeout=%d sec (nowayout=%d testmode=%d)\n",
339 chip_type, chip_rev, timeout, nowayout, testmode);
344 static void __exit it87_wdt_exit(void)
346 watchdog_unregister_device(&wdt_dev);
349 module_init(it87_wdt_init);
350 module_exit(it87_wdt_exit);
352 MODULE_AUTHOR("Oliver Schuster");
353 MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O");
354 MODULE_LICENSE("GPL");