1 // SPDX-License-Identifier: GPL-2.0+
3  *      NS pc87413-wdt Watchdog Timer driver for Linux 2.6.x.x
12  *      This material is provided "AS-IS" and at no charge.
22 #include <linux/watchdog.h>
42 #define DPFX                MODNAME " - DEBUG: "
48 #define WDCTL               0x10	/* Watchdog-Timer-Control-Register */
49 #define WDTO                0x11	/* Watchdog timeout register */
50 #define WDCFG               0x12	/* Watchdog config register */
55 static int swc_base_addr = -1;
66 /* -- Low level function ----------------------------------------*/
68 /* Select pins for Watchdog output */
92 /* Enable SWC functions */
98 	/* Step 2: Enable SWC functions */  in pc87413_enable_swc()
110 	pr_info(DPFX "pc87413 - Enable SWC functions\n");  in pc87413_enable_swc()
148 /* Set watchdog timeout to x minutes */
159 /* Enable WDEN */
163 	/* Step 6: Enable WDEN */  in pc87413_enable_wden()
166 	pr_info(DPFX "Enable WDEN\n");  in pc87413_enable_wden()
170 /* Enable SW_WD_TREN */
173 	/* Enable SW_WD_TREN */  in pc87413_enable_sw_wd_tren()
176 	pr_info(DPFX "Enable SW_WD_TREN\n");  in pc87413_enable_sw_wd_tren()
187 	pr_info(DPFX "pc87413 - Disable SW_WD_TREN\n");  in pc87413_disable_sw_wd_tren()
191 /* Enable SW_WD_TRG */
195 	/* Enable SW_WD_TRG */  in pc87413_enable_sw_wd_trg()
198 	pr_info(DPFX "pc87413 - Enable SW_WD_TRG\n");  in pc87413_enable_sw_wd_trg()
213 /* -- Higher level functions ------------------------------------*/
215 /* Enable the watchdog */
230 /* Disable the watchdog */
244 /* Refresh the watchdog */
261 /* -- File operations -------------------------------------------*/
272 	/* /dev/watchdog can only be opened once */  in pc87413_open()
275 		return -EBUSY;  in pc87413_open()
283 	pr_info("Watchdog enabled. Timeout set to %d minute(s).\n", timeout);  in pc87413_open()
293  *	The watchdog has a configurable API. There is a religious dispute
294  *	between people who want their watchdog to be able to shut down and
295  *	those who want to be sure if the watchdog manager dies the machine
306 		pr_info("Watchdog disabled, sleeping again...\n");  in pc87413_release()
308 		pr_crit("Unexpected close, not stopping watchdog!\n");  in pc87413_release()
319  *      return, if the watchdog is enabled (timeout is set...)
330  *	@file: file handle to the watchdog
335  *	A write to a watchdog device is defined as a keepalive signal. Any
355 					return -EFAULT;  in pc87413_write()
370  *	@cmd: watchdog command
373  *	The watchdog API defines a common set of functions for all watchdogs
393 		.identity         = "PC87413(HF/F) watchdog",  in pc87413_ioctl()
401 					sizeof(ident)) ? -EFAULT : 0;  in pc87413_ioctl()
408 		int options, retval = -EINVAL;  in pc87413_ioctl()
410 			return -EFAULT;  in pc87413_ioctl()
429 			return -EFAULT;  in pc87413_ioctl()
433 			return -EINVAL;  in pc87413_ioctl()
441 		return -ENOTTY;  in pc87413_ioctl()
445 /* -- Notifier functions -----------------------------------------*/
456  *	trust me - if it happens it does suck.
469 /* -- Module's structures ---------------------------------------*/
486 	.name           = "watchdog",
490 /* -- Module init functions -------------------------------------*/
495  *	Set up the WDT watchdog board. All we have to do is grab the
508 		return -EBUSY;  in pc87413_init()
528 		ret = -EBUSY;  in pc87413_init()
548  *	Unload the watchdog. You cannot do this with any file handles open.
549  *	If your watchdog is set to continue ticking on close and you unload
560 		pr_info("Watchdog disabled\n");  in pc87413_exit()
567 	pr_info("watchdog component driver removed\n");  in pc87413_exit()
584 		"Watchdog timeout in minutes (default="
589 		"Watchdog cannot be stopped once started (default="