spi: sprd: adi: Add missing lock protection when rebooting

[ Upstream commit 91ea1d70607e374b014b4b9bea771ce661f9f64b ]

When rebooting the system, we should lock the watchdog after
configuration to make sure the watchdog can reboot the system
successfully.
Signed-off-by: NLingling Xu <ling_ling.xu@unisoc.com>
Signed-off-by: NBaolin Wang <baolin.wang@linaro.org>
Link: https://lore.kernel.org/r/7b04711127434555e3a1a86bc6be99860cd86668.1572257085.git.baolin.wang@linaro.orgSigned-off-by: NMark Brown <broonie@kernel.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/spi/spi-sprd-adi.c

@@ -367,6 +367,9 @@ static int sprd_adi_restart_handler(struct notifier_block *this,
 	val |= BIT_WDG_RUN | BIT_WDG_RST;
 	sprd_adi_write(sadi, sadi->slave_pbase + REG_WDG_CTRL, val);
 
+	/* Lock the watchdog */
+	sprd_adi_write(sadi, sadi->slave_pbase + REG_WDG_LOCK, ~WDG_UNLOCK_KEY);
+
 	mdelay(1000);
 
 	dev_emerg(sadi->dev, "Unable to restart system\n");