rtc: snvs: make sure clock is enabled for interrupt handle

During system suspend, the SNVS RTC's clock will be disabled in
noirq suspend phase, but SNVS RTC's alarm interrupt could still
arrive, system will hang if SNVS RTC driver tries to access register
without clock enabled, this patch fixes the issue of this scenario.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-snvs.c

@@ -239,6 +239,9 @@ static irqreturn_t snvs_rtc_irq_handler(int irq, void *dev_id)
 	u32 lpsr;
 	u32 events = 0;
 
+	if (data->clk)
+		clk_enable(data->clk);
+
 	regmap_read(data->regmap, data->offset + SNVS_LPSR, &lpsr);
 
 	if (lpsr & SNVS_LPSR_LPTA) {
@@ -253,6 +256,9 @@ static irqreturn_t snvs_rtc_irq_handler(int irq, void *dev_id)
 	/* clear interrupt status */
 	regmap_write(data->regmap, data->offset + SNVS_LPSR, lpsr);
 
+	if (data->clk)
+		clk_disable(data->clk);
+
 	return events ? IRQ_HANDLED : IRQ_NONE;
 }