11  * @brief Nuvoton NPCX watchdog modules driver
13  * This file contains the drivers of NPCX Watchdog module that generates the
15  * system. It also provides watchdog reset signal generation in response to a
25  *  +--->| Watchdog Prescale |--->| 8-Bit Watchdog  |-----> Watchdog Event/Reset
37 #include <zephyr/drivers/watchdog.h>
45 /* Watchdog operating frequency is fixed to LFCLK (32.768) kHz */
49  * Maximum watchdog window time. Keep the timer and watchdog clock prescaler
50  * (TWCP) to 0x5. Since the watchdog counter is 8-bits, maximum time supported
51  * by npcx watchdog is 256 * (32 * 32768) / 32768 = 8192 sec.
53  * Thus, the maximum time of watchdog set here is 64 sec.
58  * Minimum watchdog window time. Ensure we have waited at least 3 watchdog
66 /* Timeout for stopping watchdog. (Unit:ms) */
79 	/* Timestamp of touching watchdog last time */
81 	/* Timeout callback used to handle watchdog event */
83 	/* Watchdog feed timeout in milliseconds */
85 	/* Indicate whether a watchdog timeout is installed */
124 	/* If watchdog is still running? */  in wdt_wait_stopped()
129 				LOG_ERR("Timeout: stop watchdog timer!");  in wdt_wait_stopped()
147 	/* Handle watchdog event here. */  in wdt_t0out_isr()
177 	/* If watchdog is already running */  in wdt_npcx_install_timeout()
182 	/* No window watchdog support */  in wdt_npcx_install_timeout()
189 	 * Since the watchdog counter in npcx series is 8-bits, maximum time  in wdt_npcx_install_timeout()
199 	/* Save watchdog timeout */  in wdt_npcx_install_timeout()
251 	/* Configure 8-bit watchdog counter  in wdt_npcx_setup()
252 	 * Change the prescaler of watchdog clock for larger timeout  in wdt_npcx_setup()
292 	 * Ensure we have waited at least 3 watchdog ticks before  in wdt_npcx_disable()
293 	 * stopping watchdog  in wdt_npcx_disable()
301 	 * Stop and unlock watchdog by writing 87h, 61h and 63h  in wdt_npcx_disable()
312 	/* Wait until watchdog is stopped. */  in wdt_npcx_disable()
322 	/* Feed watchdog by writing 5Ch to WDSDM */  in wdt_npcx_feed()
347 	 * TWCFG (Timer Watchdog Configuration) setting  in wdt_npcx_init()
349 	 * [5]  - WDSDME   = 1: Feed watchdog by writing 5Ch to WDSDM  in wdt_npcx_init()
350 	 * [4]  - WDCT0I   = 1: Select T0IN as watchdog prescaler clock  in wdt_npcx_init()
362 	 * Plan clock frequency of T0 timer and watchdog timer as below:  in wdt_npcx_init()
364 	 * - Watchdog freq is T0CLK/32 Hz (ie. LFCLK/1024 Hz)  in wdt_npcx_init()
366 	inst->WDCP = 0x05; /* Prescaler is 32 in Watchdog Timer */  in wdt_npcx_init()