drivers/watchdog/cdns_wdt.c

1 // SPDX-License-Identifier: GPL-2.0
3  * Cadence WDT driver - Used by Xilinx Zynq
18 	u32 zmr;	/* WD Zero mode register, offset - 0x0 */
19 	u32 ccr;	/* Counter Control Register offset - 0x4 */
20 	u32 restart;	/* Restart key register, offset - 0x8 */
21 	u32 status;	/* Status Register, offset - 0xC */
32 /* Supports 1 - 516 sec */
62  * Zero Mode Register - This register controls how the time out is indicated
66 #define CDNS_WDT_ZMR_RSTEN_MASK	0x00000002 /* Enable the reset output */
68 #define CDNS_WDT_ZMR_RSTLEN_16	0x00000030 /* Reset pulse of 16 pclk cycles */
72  * Counter Control register - This register controls how fast the timer runs
73  * and the reset value and also contains the access code to allow writes to
76 #define CDNS_WDT_CCR_CRV_MASK	0x00003FFC /* Counter reset value */
85  * cdns_wdt_reset - Reload the watchdog timer (i.e. pat the watchdog).
99 	cdns_wdt_writereg(&priv->regs->restart, CDNS_WDT_RESTART_KEY);  in cdns_wdt_reset()
105  * cdns_wdt_start - Enable and start the watchdog.
117  * Clears the contents of prescaler and counter reset value. Sets the
121  * Sets the WDT (WDEN bit) and either the Reset signal(RSTEN bit)
125  * Return: Upon success 0, failure -1.
136 		return -1;  in cdns_wdt_start()
142 		return -1;  in cdns_wdt_start()
147 		timeout = priv->timeout;  in cdns_wdt_start()
162 	 * counter reset to be written to control register.  in cdns_wdt_start()
170 	cdns_wdt_writereg(&priv->regs->zmr, CDNS_WDT_ZMR_ZKEY_VAL);  in cdns_wdt_start()
176 	cdns_wdt_writereg(&priv->regs->ccr, data);  in cdns_wdt_start()
181 	/* Reset on timeout if specified in device tree. */  in cdns_wdt_start()
182 	if (priv->rst) {  in cdns_wdt_start()
190 	cdns_wdt_writereg(&priv->regs->zmr, data);  in cdns_wdt_start()
191 	cdns_wdt_writereg(&priv->regs->restart, CDNS_WDT_RESTART_KEY);  in cdns_wdt_start()
197  * cdns_wdt_stop - Stop the watchdog.
210 	cdns_wdt_writereg(&priv->regs->zmr,  in cdns_wdt_stop()
217  * cdns_wdt_probe - Probe call for the device.
225 	debug("%s: Probing wdt%u\n", __func__, dev->seq);  in cdns_wdt_probe()
234 	priv->regs = (struct cdns_regs *)dev_read_addr(dev);  in cdns_wdt_ofdata_to_platdata()
235 	if (IS_ERR(priv->regs))  in cdns_wdt_ofdata_to_platdata()
236 		return PTR_ERR(priv->regs);  in cdns_wdt_ofdata_to_platdata()
238 	priv->timeout = dev_read_u32_default(dev, "timeout-sec",  in cdns_wdt_ofdata_to_platdata()
241 	priv->rst = dev_read_bool(dev, "reset-on-timeout");  in cdns_wdt_ofdata_to_platdata()
243 	debug("%s: timeout %d, reset %d\n", __func__, priv->timeout, priv->rst);  in cdns_wdt_ofdata_to_platdata()
250 	.reset = cdns_wdt_reset,
256 	{ .compatible = "cdns,wdt-r1p2" },
264 	.probe = cdns_wdt_probe,