[PATCH 1/2] rtc: snvs: Make SNVS clock always prepared

[PATCH 1/2] rtc: snvs: Make SNVS clock always prepared

[Anson Huang]

In IRQ handler, ONLY clock enable/disable is called due to
clock prepare can NOT be called in interrupt context, but
clock enable/disable will return failure if prepare count
is 0, to fix this issue, just make SNVS clock always prepared
there, the SNVS clock has no prepare function implemented,
so it won't impact anything.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
---
 drivers/rtc/rtc-snvs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-snvs.c b/drivers/rtc/rtc-snvs.c
index 35ee08a..b9371f4 100644
--- a/drivers/rtc/rtc-snvs.c
+++ b/drivers/rtc/rtc-snvs.c
@@ -362,7 +362,7 @@ static int __maybe_unused snvs_rtc_suspend_noirq(struct device *dev)
 	struct snvs_rtc_data *data = dev_get_drvdata(dev);
 
 	if (data->clk)
-		clk_disable_unprepare(data->clk);
+		clk_disable(data->clk);
 
 	return 0;
 }
@@ -372,7 +372,7 @@ static int __maybe_unused snvs_rtc_resume_noirq(struct device *dev)
 	struct snvs_rtc_data *data = dev_get_drvdata(dev);
 
 	if (data->clk)
-		return clk_prepare_enable(data->clk);
+		return clk_enable(data->clk);
 
 	return 0;
 }
-- 
2.7.4

[PATCH 2/2] rtc: snvs: Add necessary clock operations for RTC APIs

[Anson Huang]

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>
---
 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 b9371f4..0263d99 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);
 }
 
-- 
2.7.4

Re: [PATCH 1/2] rtc: snvs: Make SNVS clock always prepared

[Alexandre Belloni]

On Fri, 22 May 2020 10:19:55 +0800, Anson Huang wrote:
> In IRQ handler, ONLY clock enable/disable is called due to
> clock prepare can NOT be called in interrupt context, but
> clock enable/disable will return failure if prepare count
> is 0, to fix this issue, just make SNVS clock always prepared
> there, the SNVS clock has no prepare function implemented,
> so it won't impact anything.

Applied, thanks!

[1/2] rtc: snvs: Make SNVS clock always prepared
      commit: 20af67700bc39bccd838414128f63a72965de6e7
[2/2] rtc: snvs: Add necessary clock operations for RTC APIs
      commit: 4b957bde561f3a56865395be06f1be2c196b0b5e

Best regards,
-- 
Alexandre Belloni <alexandre.belloni@bootlin.com>