mfd: wm8350-i2c: Make sure the i2c regmap functions are compiled
[linux/fpc-iii.git] / drivers / watchdog / smsc37b787_wdt.c
blob6d665f9c1d586393224594df0d2ae57bd9412b29
1 /*
2 * SMsC 37B787 Watchdog Timer driver for Linux 2.6.x.x
4 * Based on acquirewdt.c by Alan Cox <alan@lxorguk.ukuu.org.uk>
5 * and some other existing drivers
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
12 * The authors do NOT admit liability nor provide warranty for
13 * any of this software. This material is provided "AS-IS" in
14 * the hope that it may be useful for others.
16 * (C) Copyright 2003-2006 Sven Anders <anders@anduras.de>
18 * History:
19 * 2003 - Created version 1.0 for Linux 2.4.x.
20 * 2006 - Ported to Linux 2.6, added nowayout and MAGICCLOSE
21 * features. Released version 1.1
23 * Theory of operation:
25 * A Watchdog Timer (WDT) is a hardware circuit that can
26 * reset the computer system in case of a software fault.
27 * You probably knew that already.
29 * Usually a userspace daemon will notify the kernel WDT driver
30 * via the /dev/watchdog special device file that userspace is
31 * still alive, at regular intervals. When such a notification
32 * occurs, the driver will usually tell the hardware watchdog
33 * that everything is in order, and that the watchdog should wait
34 * for yet another little while to reset the system.
35 * If userspace fails (RAM error, kernel bug, whatever), the
36 * notifications cease to occur, and the hardware watchdog will
37 * reset the system (causing a reboot) after the timeout occurs.
39 * Create device with:
40 * mknod /dev/watchdog c 10 130
42 * For an example userspace keep-alive daemon, see:
43 * Documentation/watchdog/wdt.txt
46 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
48 #include <linux/module.h>
49 #include <linux/moduleparam.h>
50 #include <linux/types.h>
51 #include <linux/miscdevice.h>
52 #include <linux/watchdog.h>
53 #include <linux/delay.h>
54 #include <linux/fs.h>
55 #include <linux/ioport.h>
56 #include <linux/notifier.h>
57 #include <linux/reboot.h>
58 #include <linux/init.h>
59 #include <linux/spinlock.h>
60 #include <linux/io.h>
61 #include <linux/uaccess.h>
64 /* enable support for minutes as units? */
65 /* (does not always work correctly, so disabled by default!) */
66 #define SMSC_SUPPORT_MINUTES
67 #undef SMSC_SUPPORT_MINUTES
69 #define MAX_TIMEOUT 255
71 #define UNIT_SECOND 0
72 #define UNIT_MINUTE 1
74 #define VERSION "1.1"
76 #define IOPORT 0x3F0
77 #define IOPORT_SIZE 2
78 #define IODEV_NO 8
80 static int unit = UNIT_SECOND; /* timer's unit */
81 static int timeout = 60; /* timeout value: default is 60 "units" */
82 static unsigned long timer_enabled; /* is the timer enabled? */
84 static char expect_close; /* is the close expected? */
86 static DEFINE_SPINLOCK(io_lock);/* to guard the watchdog from io races */
88 static bool nowayout = WATCHDOG_NOWAYOUT;
90 /* -- Low level function ----------------------------------------*/
92 /* unlock the IO chip */
94 static inline void open_io_config(void)
96 outb(0x55, IOPORT);
97 mdelay(1);
98 outb(0x55, IOPORT);
101 /* lock the IO chip */
102 static inline void close_io_config(void)
104 outb(0xAA, IOPORT);
107 /* select the IO device */
108 static inline void select_io_device(unsigned char devno)
110 outb(0x07, IOPORT);
111 outb(devno, IOPORT+1);
114 /* write to the control register */
115 static inline void write_io_cr(unsigned char reg, unsigned char data)
117 outb(reg, IOPORT);
118 outb(data, IOPORT+1);
121 /* read from the control register */
122 static inline char read_io_cr(unsigned char reg)
124 outb(reg, IOPORT);
125 return inb(IOPORT+1);
128 /* -- Medium level functions ------------------------------------*/
130 static inline void gpio_bit12(unsigned char reg)
132 /* -- General Purpose I/O Bit 1.2 --
133 * Bit 0, In/Out: 0 = Output, 1 = Input
134 * Bit 1, Polarity: 0 = No Invert, 1 = Invert
135 * Bit 2, Group Enable Intr.: 0 = Disable, 1 = Enable
136 * Bit 3/4, Function select: 00 = GPI/O, 01 = WDT, 10 = P17,
137 * 11 = Either Edge Triggered Intr. 2
138 * Bit 5/6 (Reserved)
139 * Bit 7, Output Type: 0 = Push Pull Bit, 1 = Open Drain
141 write_io_cr(0xE2, reg);
144 static inline void gpio_bit13(unsigned char reg)
146 /* -- General Purpose I/O Bit 1.3 --
147 * Bit 0, In/Out: 0 = Output, 1 = Input
148 * Bit 1, Polarity: 0 = No Invert, 1 = Invert
149 * Bit 2, Group Enable Intr.: 0 = Disable, 1 = Enable
150 * Bit 3, Function select: 0 = GPI/O, 1 = LED
151 * Bit 4-6 (Reserved)
152 * Bit 7, Output Type: 0 = Push Pull Bit, 1 = Open Drain
154 write_io_cr(0xE3, reg);
157 static inline void wdt_timer_units(unsigned char new_units)
159 /* -- Watchdog timer units --
160 * Bit 0-6 (Reserved)
161 * Bit 7, WDT Time-out Value Units Select
162 * (0 = Minutes, 1 = Seconds)
164 write_io_cr(0xF1, new_units);
167 static inline void wdt_timeout_value(unsigned char new_timeout)
169 /* -- Watchdog Timer Time-out Value --
170 * Bit 0-7 Binary coded units (0=Disabled, 1..255)
172 write_io_cr(0xF2, new_timeout);
175 static inline void wdt_timer_conf(unsigned char conf)
177 /* -- Watchdog timer configuration --
178 * Bit 0 Joystick enable: 0* = No Reset, 1 = Reset WDT upon
179 * Gameport I/O
180 * Bit 1 Keyboard enable: 0* = No Reset, 1 = Reset WDT upon KBD Intr.
181 * Bit 2 Mouse enable: 0* = No Reset, 1 = Reset WDT upon Mouse Intr
182 * Bit 3 Reset the timer
183 * (Wrong in SMsC documentation? Given as: PowerLED Timout
184 * Enabled)
185 * Bit 4-7 WDT Interrupt Mapping: (0000* = Disabled,
186 * 0001=IRQ1, 0010=(Invalid), 0011=IRQ3 to 1111=IRQ15)
188 write_io_cr(0xF3, conf);
191 static inline void wdt_timer_ctrl(unsigned char reg)
193 /* -- Watchdog timer control --
194 * Bit 0 Status Bit: 0 = Timer counting, 1 = Timeout occurred
195 * Bit 1 Power LED Toggle: 0 = Disable Toggle, 1 = Toggle at 1 Hz
196 * Bit 2 Force Timeout: 1 = Forces WD timeout event (self-cleaning)
197 * Bit 3 P20 Force Timeout enabled:
198 * 0 = P20 activity does not generate the WD timeout event
199 * 1 = P20 Allows rising edge of P20, from the keyboard
200 * controller, to force the WD timeout event.
201 * Bit 4 (Reserved)
202 * -- Soft power management --
203 * Bit 5 Stop Counter: 1 = Stop software power down counter
204 * set via register 0xB8, (self-cleaning)
205 * (Upon read: 0 = Counter running, 1 = Counter stopped)
206 * Bit 6 Restart Counter: 1 = Restart software power down counter
207 * set via register 0xB8, (self-cleaning)
208 * Bit 7 SPOFF: 1 = Force software power down (self-cleaning)
210 write_io_cr(0xF4, reg);
213 /* -- Higher level functions ------------------------------------*/
215 /* initialize watchdog */
217 static void wb_smsc_wdt_initialize(void)
219 unsigned char old;
221 spin_lock(&io_lock);
222 open_io_config();
223 select_io_device(IODEV_NO);
225 /* enable the watchdog */
226 gpio_bit13(0x08); /* Select pin 80 = LED not GPIO */
227 gpio_bit12(0x0A); /* Set pin 79 = WDT not
228 GPIO/Output/Polarity=Invert */
229 /* disable the timeout */
230 wdt_timeout_value(0);
232 /* reset control register */
233 wdt_timer_ctrl(0x00);
235 /* reset configuration register */
236 wdt_timer_conf(0x00);
238 /* read old (timer units) register */
239 old = read_io_cr(0xF1) & 0x7F;
240 if (unit == UNIT_SECOND)
241 old |= 0x80; /* set to seconds */
243 /* set the watchdog timer units */
244 wdt_timer_units(old);
246 close_io_config();
247 spin_unlock(&io_lock);
250 /* shutdown the watchdog */
252 static void wb_smsc_wdt_shutdown(void)
254 spin_lock(&io_lock);
255 open_io_config();
256 select_io_device(IODEV_NO);
258 /* disable the watchdog */
259 gpio_bit13(0x09);
260 gpio_bit12(0x09);
262 /* reset watchdog config register */
263 wdt_timer_conf(0x00);
265 /* reset watchdog control register */
266 wdt_timer_ctrl(0x00);
268 /* disable timeout */
269 wdt_timeout_value(0x00);
271 close_io_config();
272 spin_unlock(&io_lock);
275 /* set timeout => enable watchdog */
277 static void wb_smsc_wdt_set_timeout(unsigned char new_timeout)
279 spin_lock(&io_lock);
280 open_io_config();
281 select_io_device(IODEV_NO);
283 /* set Power LED to blink, if we enable the timeout */
284 wdt_timer_ctrl((new_timeout == 0) ? 0x00 : 0x02);
286 /* set timeout value */
287 wdt_timeout_value(new_timeout);
289 close_io_config();
290 spin_unlock(&io_lock);
293 /* get timeout */
295 static unsigned char wb_smsc_wdt_get_timeout(void)
297 unsigned char set_timeout;
299 spin_lock(&io_lock);
300 open_io_config();
301 select_io_device(IODEV_NO);
302 set_timeout = read_io_cr(0xF2);
303 close_io_config();
304 spin_unlock(&io_lock);
306 return set_timeout;
309 /* disable watchdog */
311 static void wb_smsc_wdt_disable(void)
313 /* set the timeout to 0 to disable the watchdog */
314 wb_smsc_wdt_set_timeout(0);
317 /* enable watchdog by setting the current timeout */
319 static void wb_smsc_wdt_enable(void)
321 /* set the current timeout... */
322 wb_smsc_wdt_set_timeout(timeout);
325 /* reset the timer */
327 static void wb_smsc_wdt_reset_timer(void)
329 spin_lock(&io_lock);
330 open_io_config();
331 select_io_device(IODEV_NO);
333 /* reset the timer */
334 wdt_timeout_value(timeout);
335 wdt_timer_conf(0x08);
337 close_io_config();
338 spin_unlock(&io_lock);
341 /* return, if the watchdog is enabled (timeout is set...) */
343 static int wb_smsc_wdt_status(void)
345 return (wb_smsc_wdt_get_timeout() == 0) ? 0 : WDIOF_KEEPALIVEPING;
349 /* -- File operations -------------------------------------------*/
351 /* open => enable watchdog and set initial timeout */
353 static int wb_smsc_wdt_open(struct inode *inode, struct file *file)
355 /* /dev/watchdog can only be opened once */
357 if (test_and_set_bit(0, &timer_enabled))
358 return -EBUSY;
360 if (nowayout)
361 __module_get(THIS_MODULE);
363 /* Reload and activate timer */
364 wb_smsc_wdt_enable();
366 pr_info("Watchdog enabled. Timeout set to %d %s\n",
367 timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)");
369 return nonseekable_open(inode, file);
372 /* close => shut off the timer */
374 static int wb_smsc_wdt_release(struct inode *inode, struct file *file)
376 /* Shut off the timer. */
378 if (expect_close == 42) {
379 wb_smsc_wdt_disable();
380 pr_info("Watchdog disabled, sleeping again...\n");
381 } else {
382 pr_crit("Unexpected close, not stopping watchdog!\n");
383 wb_smsc_wdt_reset_timer();
386 clear_bit(0, &timer_enabled);
387 expect_close = 0;
388 return 0;
391 /* write => update the timer to keep the machine alive */
393 static ssize_t wb_smsc_wdt_write(struct file *file, const char __user *data,
394 size_t len, loff_t *ppos)
396 /* See if we got the magic character 'V' and reload the timer */
397 if (len) {
398 if (!nowayout) {
399 size_t i;
401 /* reset expect flag */
402 expect_close = 0;
404 /* scan to see whether or not we got the
405 magic character */
406 for (i = 0; i != len; i++) {
407 char c;
408 if (get_user(c, data + i))
409 return -EFAULT;
410 if (c == 'V')
411 expect_close = 42;
415 /* someone wrote to us, we should reload the timer */
416 wb_smsc_wdt_reset_timer();
418 return len;
421 /* ioctl => control interface */
423 static long wb_smsc_wdt_ioctl(struct file *file,
424 unsigned int cmd, unsigned long arg)
426 int new_timeout;
428 union {
429 struct watchdog_info __user *ident;
430 int __user *i;
431 } uarg;
433 static const struct watchdog_info ident = {
434 .options = WDIOF_KEEPALIVEPING |
435 WDIOF_SETTIMEOUT |
436 WDIOF_MAGICCLOSE,
437 .firmware_version = 0,
438 .identity = "SMsC 37B787 Watchdog",
441 uarg.i = (int __user *)arg;
443 switch (cmd) {
444 case WDIOC_GETSUPPORT:
445 return copy_to_user(uarg.ident, &ident, sizeof(ident))
446 ? -EFAULT : 0;
447 case WDIOC_GETSTATUS:
448 return put_user(wb_smsc_wdt_status(), uarg.i);
449 case WDIOC_GETBOOTSTATUS:
450 return put_user(0, uarg.i);
451 case WDIOC_SETOPTIONS:
453 int options, retval = -EINVAL;
455 if (get_user(options, uarg.i))
456 return -EFAULT;
458 if (options & WDIOS_DISABLECARD) {
459 wb_smsc_wdt_disable();
460 retval = 0;
462 if (options & WDIOS_ENABLECARD) {
463 wb_smsc_wdt_enable();
464 retval = 0;
466 return retval;
468 case WDIOC_KEEPALIVE:
469 wb_smsc_wdt_reset_timer();
470 return 0;
471 case WDIOC_SETTIMEOUT:
472 if (get_user(new_timeout, uarg.i))
473 return -EFAULT;
474 /* the API states this is given in secs */
475 if (unit == UNIT_MINUTE)
476 new_timeout /= 60;
477 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
478 return -EINVAL;
479 timeout = new_timeout;
480 wb_smsc_wdt_set_timeout(timeout);
481 /* fall through and return the new timeout... */
482 case WDIOC_GETTIMEOUT:
483 new_timeout = timeout;
484 if (unit == UNIT_MINUTE)
485 new_timeout *= 60;
486 return put_user(new_timeout, uarg.i);
487 default:
488 return -ENOTTY;
492 /* -- Notifier funtions -----------------------------------------*/
494 static int wb_smsc_wdt_notify_sys(struct notifier_block *this,
495 unsigned long code, void *unused)
497 if (code == SYS_DOWN || code == SYS_HALT) {
498 /* set timeout to 0, to avoid possible race-condition */
499 timeout = 0;
500 wb_smsc_wdt_disable();
502 return NOTIFY_DONE;
505 /* -- Module's structures ---------------------------------------*/
507 static const struct file_operations wb_smsc_wdt_fops = {
508 .owner = THIS_MODULE,
509 .llseek = no_llseek,
510 .write = wb_smsc_wdt_write,
511 .unlocked_ioctl = wb_smsc_wdt_ioctl,
512 .open = wb_smsc_wdt_open,
513 .release = wb_smsc_wdt_release,
516 static struct notifier_block wb_smsc_wdt_notifier = {
517 .notifier_call = wb_smsc_wdt_notify_sys,
520 static struct miscdevice wb_smsc_wdt_miscdev = {
521 .minor = WATCHDOG_MINOR,
522 .name = "watchdog",
523 .fops = &wb_smsc_wdt_fops,
526 /* -- Module init functions -------------------------------------*/
528 /* module's "constructor" */
530 static int __init wb_smsc_wdt_init(void)
532 int ret;
534 pr_info("SMsC 37B787 watchdog component driver "
535 VERSION " initialising...\n");
537 if (!request_region(IOPORT, IOPORT_SIZE, "SMsC 37B787 watchdog")) {
538 pr_err("Unable to register IO port %#x\n", IOPORT);
539 ret = -EBUSY;
540 goto out_pnp;
543 /* set new maximum, if it's too big */
544 if (timeout > MAX_TIMEOUT)
545 timeout = MAX_TIMEOUT;
547 /* init the watchdog timer */
548 wb_smsc_wdt_initialize();
550 ret = register_reboot_notifier(&wb_smsc_wdt_notifier);
551 if (ret) {
552 pr_err("Unable to register reboot notifier err = %d\n", ret);
553 goto out_io;
556 ret = misc_register(&wb_smsc_wdt_miscdev);
557 if (ret) {
558 pr_err("Unable to register miscdev on minor %d\n",
559 WATCHDOG_MINOR);
560 goto out_rbt;
563 /* output info */
564 pr_info("Timeout set to %d %s\n",
565 timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)");
566 pr_info("Watchdog initialized and sleeping (nowayout=%d)...\n",
567 nowayout);
568 out_clean:
569 return ret;
571 out_rbt:
572 unregister_reboot_notifier(&wb_smsc_wdt_notifier);
574 out_io:
575 release_region(IOPORT, IOPORT_SIZE);
577 out_pnp:
578 goto out_clean;
581 /* module's "destructor" */
583 static void __exit wb_smsc_wdt_exit(void)
585 /* Stop the timer before we leave */
586 if (!nowayout) {
587 wb_smsc_wdt_shutdown();
588 pr_info("Watchdog disabled\n");
591 misc_deregister(&wb_smsc_wdt_miscdev);
592 unregister_reboot_notifier(&wb_smsc_wdt_notifier);
593 release_region(IOPORT, IOPORT_SIZE);
595 pr_info("SMsC 37B787 watchdog component driver removed\n");
598 module_init(wb_smsc_wdt_init);
599 module_exit(wb_smsc_wdt_exit);
601 MODULE_AUTHOR("Sven Anders <anders@anduras.de>");
602 MODULE_DESCRIPTION("Driver for SMsC 37B787 watchdog component (Version "
603 VERSION ")");
604 MODULE_LICENSE("GPL");
606 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
608 #ifdef SMSC_SUPPORT_MINUTES
609 module_param(unit, int, 0);
610 MODULE_PARM_DESC(unit,
611 "set unit to use, 0=seconds or 1=minutes, default is 0");
612 #endif
614 module_param(timeout, int, 0);
615 MODULE_PARM_DESC(timeout, "range is 1-255 units, default is 60");
617 module_param(nowayout, bool, 0);
618 MODULE_PARM_DESC(nowayout,
619 "Watchdog cannot be stopped once started (default="
620 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");