[v2] rtc: Fix suspend/resume for APM X-Gene SoC RTC driver

[Loc Ho <lho@apm.com>]

This patch fixes suspend/resume functions properly for the APM X-Gene
SoC RTC driver. This patch requires the merged v2 of the APM X-Gene 
SoC RTC driver.

Signed-off-by: Loc Ho <lho@apm.com>
Reviewed-by: Mark Brown <broonie@linaro.org>
---
 drivers/rtc/rtc-xgene.c |   41 ++++++++++++++++++++++++++++++++---------
 1 files changed, 32 insertions(+), 9 deletions(-)

diff --git a/drivers/rtc/rtc-xgene.c b/drivers/rtc/rtc-xgene.c
index 14129cc..d533edd 100644
--- a/drivers/rtc/rtc-xgene.c
+++ b/drivers/rtc/rtc-xgene.c
@@ -52,6 +52,7 @@ struct xgene_rtc_dev {
 	void __iomem *csr_base;
 	struct clk *clk;
 	unsigned int irq_wake;
+	unsigned int irq_enabled;
 };
 
 static int xgene_rtc_read_time(struct device *dev, struct rtc_time *tm)
@@ -104,15 +105,19 @@ static int xgene_rtc_alarm_irq_enable(struct device *dev, u32 enabled)
 	return 0;
 }
 
+static int xgene_rtc_alarm_irq_enabled(struct device *dev)
+{
+	struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
+
+	return readl(pdata->csr_base + RTC_CCR) & RTC_CCR_IE ? 1 : 0;
+}
+
 static int xgene_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
-	unsigned long rtc_time;
 	unsigned long alarm_time;
 
-	rtc_time = readl(pdata->csr_base + RTC_CCVR);
 	rtc_tm_to_time(&alrm->time, &alarm_time);
-
 	pdata->alarm_time = alarm_time;
 	writel((u32) pdata->alarm_time, pdata->csr_base + RTC_CMR);
 
@@ -180,12 +185,18 @@ static int xgene_rtc_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev, "Couldn't get the clock for RTC\n");
 		return -ENODEV;
 	}
-	clk_prepare_enable(pdata->clk);
+	ret = clk_prepare_enable(pdata->clk);
+	if (ret)
+		return ret;
 
 	/* Turn on the clock and the crystal */
 	writel(RTC_CCR_EN, pdata->csr_base + RTC_CCR);
 
-	device_init_wakeup(&pdev->dev, 1);
+	ret = device_init_wakeup(&pdev->dev, 1);
+	if (ret) {
+		clk_disable_unprepare(pdata->clk);
+		return ret;
+	}
 
 	pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 					 &xgene_rtc_ops, THIS_MODULE);
@@ -218,14 +229,20 @@ static int xgene_rtc_suspend(struct device *dev)
 	int irq;
 
 	irq = platform_get_irq(pdev, 0);
+
+	/*
+	 * If this RTC alarm will be used for waking the system up,
+	 * don't disable it of course. Else we just disable the alarm
+	 * and await suspension.
+	 */
 	if (device_may_wakeup(&pdev->dev)) {
 		if (!enable_irq_wake(irq))
 			pdata->irq_wake = 1;
 	} else {
+		pdata->irq_enabled = xgene_rtc_alarm_irq_enabled(dev);
 		xgene_rtc_alarm_irq_enable(dev, 0);
-		clk_disable(pdata->clk);
+		clk_disable_unprepare(pdata->clk);
 	}
-
 	return 0;
 }
 
@@ -234,16 +251,22 @@ static int xgene_rtc_resume(struct device *dev)
 	struct platform_device *pdev = to_platform_device(dev);
 	struct xgene_rtc_dev *pdata = platform_get_drvdata(pdev);
 	int irq;
+	int rc;
 
 	irq = platform_get_irq(pdev, 0);
+
 	if (device_may_wakeup(&pdev->dev)) {
 		if (pdata->irq_wake) {
 			disable_irq_wake(irq);
 			pdata->irq_wake = 0;
 		}
 	} else {
-		clk_enable(pdata->clk);
-		xgene_rtc_alarm_irq_enable(dev, 1);
+		rc = clk_prepare_enable(pdata->clk);
+		if (rc) {
+			dev_err(dev, "Unable to enable clock error %d\n", rc);
+			return rc;
+		}
+		xgene_rtc_alarm_irq_enable(dev, pdata->irq_enabled);
 	}
 
 	return 0;