From: Anson Huang <Anson.Huang@nxp.com>
Date: Fri, 22 May 2020 10:19:56 +0800
Subject: rtc: snvs: Add necessary clock operations for RTC APIs
Git-commit: 4b957bde561f3a56865395be06f1be2c196b0b5e
Patch-mainline: v5.8-rc1
References: jsc#SLE-16106

There could be still RTC registers access after RTC suspend
with clock disabled, need to add clock operations for each
RTC API to make sure accessing RTC registers is successfully.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/1590113996-31845-2-git-send-email-Anson.Huang@nxp.com

Acked-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
---
 drivers/rtc/rtc-snvs.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 53 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-snvs.c b/drivers/rtc/rtc-snvs.c
index b9371f471abe..0263d996b8a8 100644
--- a/drivers/rtc/rtc-snvs.c
+++ b/drivers/rtc/rtc-snvs.c
@@ -148,10 +148,21 @@ static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable)
 static int snvs_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
 	struct snvs_rtc_data *data = dev_get_drvdata(dev);
-	unsigned long time = rtc_read_lp_counter(data);
+	unsigned long time;
+	int ret;
+
+	if (data->clk) {
+		ret = clk_enable(data->clk);
+		if (ret)
+			return ret;
+	}
 
+	time = rtc_read_lp_counter(data);
 	rtc_time64_to_tm(time, tm);
 
+	if (data->clk)
+		clk_disable(data->clk);
+
 	return 0;
 }
 
@@ -161,6 +172,12 @@ static int snvs_rtc_set_time(struct device *dev, struct rtc_time *tm)
 	unsigned long time = rtc_tm_to_time64(tm);
 	int ret;
 
+	if (data->clk) {
+		ret = clk_enable(data->clk);
+		if (ret)
+			return ret;
+	}
+
 	/* Disable RTC first */
 	ret = snvs_rtc_enable(data, false);
 	if (ret)
@@ -173,6 +190,9 @@ static int snvs_rtc_set_time(struct device *dev, struct rtc_time *tm)
 	/* Enable RTC again */
 	ret = snvs_rtc_enable(data, true);
 
+	if (data->clk)
+		clk_disable(data->clk);
+
 	return ret;
 }
 
@@ -180,6 +200,13 @@ static int snvs_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct snvs_rtc_data *data = dev_get_drvdata(dev);
 	u32 lptar, lpsr;
+	int ret;
+
+	if (data->clk) {
+		ret = clk_enable(data->clk);
+		if (ret)
+			return ret;
+	}
 
 	regmap_read(data->regmap, data->offset + SNVS_LPTAR, &lptar);
 	rtc_time64_to_tm(lptar, &alrm->time);
@@ -187,18 +214,33 @@ static int snvs_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 	regmap_read(data->regmap, data->offset + SNVS_LPSR, &lpsr);
 	alrm->pending = (lpsr & SNVS_LPSR_LPTA) ? 1 : 0;
 
+	if (data->clk)
+		clk_disable(data->clk);
+
 	return 0;
 }
 
 static int snvs_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
 {
 	struct snvs_rtc_data *data = dev_get_drvdata(dev);
+	int ret;
+
+	if (data->clk) {
+		ret = clk_enable(data->clk);
+		if (ret)
+			return ret;
+	}
 
 	regmap_update_bits(data->regmap, data->offset + SNVS_LPCR,
 			   (SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN),
 			   enable ? (SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN) : 0);
 
-	return rtc_write_sync_lp(data);
+	ret = rtc_write_sync_lp(data);
+
+	if (data->clk)
+		clk_disable(data->clk);
+
+	return ret;
 }
 
 static int snvs_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
@@ -207,6 +249,12 @@ static int snvs_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 	unsigned long time = rtc_tm_to_time64(&alrm->time);
 	int ret;
 
+	if (data->clk) {
+		ret = clk_enable(data->clk);
+		if (ret)
+			return ret;
+	}
+
 	regmap_update_bits(data->regmap, data->offset + SNVS_LPCR, SNVS_LPCR_LPTA_EN, 0);
 	ret = rtc_write_sync_lp(data);
 	if (ret)
@@ -216,6 +264,9 @@ static int snvs_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 	/* Clear alarm interrupt status bit */
 	regmap_write(data->regmap, data->offset + SNVS_LPSR, SNVS_LPSR_LPTA);
 
+	if (data->clk)
+		clk_disable(data->clk);
+
 	return snvs_rtc_alarm_irq_enable(dev, alrm->enabled);
 }