Linux-libre 4.7.1-gnupck-4.7.1-gnu

1 files changed, 61 insertions, 13 deletions

diff --git a/drivers/rtc/rtc-zynqmp.c b/drivers/rtc/rtc-zynqmp.c
index 8b28762f0..da18a8ae3 100644
--- a/drivers/rtc/rtc-zynqmp.c
+++ b/drivers/rtc/rtc-zynqmp.c
@@ -45,6 +45,7 @@
 #define RTC_INT_SEC		BIT(0)
 #define RTC_INT_ALRM		BIT(1)
 #define RTC_OSC_EN		BIT(24)
+#define RTC_BATT_EN		BIT(31)
 
 #define RTC_CALIB_DEF		0x198233
 #define RTC_CALIB_MASK		0x1FFFFF
@@ -55,6 +56,7 @@ struct xlnx_rtc_dev {
 	void __iomem		*reg_base;
 	int			alarm_irq;
 	int			sec_irq;
+	int			calibval;
 };
 
 static int xlnx_rtc_set_time(struct device *dev, struct rtc_time *tm)
@@ -62,21 +64,63 @@ static int xlnx_rtc_set_time(struct device *dev, struct rtc_time *tm)
 	struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
 	unsigned long new_time;
 
-	new_time = rtc_tm_to_time64(tm);
+	/*
+	 * The value written will be updated after 1 sec into the
+	 * seconds read register, so we need to program time +1 sec
+	 * to get the correct time on read.
+	 */
+	new_time = rtc_tm_to_time64(tm) + 1;
 
 	if (new_time > RTC_SEC_MAX_VAL)
 		return -EINVAL;
 
+	/*
+	 * Writing into calibration register will clear the Tick Counter and
+	 * force the next second to be signaled exactly in 1 second period
+	 */
+	xrtcdev->calibval &= RTC_CALIB_MASK;
+	writel(xrtcdev->calibval, (xrtcdev->reg_base + RTC_CALIB_WR));
+
 	writel(new_time, xrtcdev->reg_base + RTC_SET_TM_WR);
 
+	/*
+	 * Clear the rtc interrupt status register after setting the
+	 * time. During a read_time function, the code should read the
+	 * RTC_INT_STATUS register and if bit 0 is still 0, it means
+	 * that one second has not elapsed yet since RTC was set and
+	 * the current time should be read from SET_TIME_READ register;
+	 * otherwise, CURRENT_TIME register is read to report the time
+	 */
+	writel(RTC_INT_SEC, xrtcdev->reg_base + RTC_INT_STS);
+
 	return 0;
 }
 
 static int xlnx_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
+	u32 status;
+	unsigned long read_time;
 	struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
 
-	rtc_time64_to_tm(readl(xrtcdev->reg_base + RTC_CUR_TM), tm);
+	status = readl(xrtcdev->reg_base + RTC_INT_STS);
+
+	if (status & RTC_INT_SEC) {
+		/*
+		 * RTC has updated the CURRENT_TIME with the time written into
+		 * SET_TIME_WRITE register.
+		 */
+		rtc_time64_to_tm(readl(xrtcdev->reg_base + RTC_CUR_TM), tm);
+	} else {
+		/*
+		 * Time written in SET_TIME_WRITE has not yet updated into
+		 * the seconds read register, so read the time from the
+		 * SET_TIME_WRITE instead of CURRENT_TIME register.
+		 * Since we add +1 sec while writing, we need to -1 sec while
+		 * reading.
+		 */
+		read_time = readl(xrtcdev->reg_base + RTC_SET_TM_RD) - 1;
+		rtc_time64_to_tm(read_time, tm);
+	}
 
 	return rtc_valid_tm(tm);
 }
@@ -120,16 +164,23 @@ static int xlnx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 	return 0;
 }
 
-static void xlnx_init_rtc(struct xlnx_rtc_dev *xrtcdev, u32 calibval)
+static void xlnx_init_rtc(struct xlnx_rtc_dev *xrtcdev)
 {
+	u32 rtc_ctrl;
+
+	/* Enable RTC switch to battery when VCC_PSAUX is not available */
+	rtc_ctrl = readl(xrtcdev->reg_base + RTC_CTRL);
+	rtc_ctrl |= RTC_BATT_EN;
+	writel(rtc_ctrl, xrtcdev->reg_base + RTC_CTRL);
+
 	/*
 	 * Based on crystal freq of 33.330 KHz
 	 * set the seconds counter and enable, set fractions counter
 	 * to default value suggested as per design spec
 	 * to correct RTC delay in frequency over period of time.
 	 */
-	calibval &= RTC_CALIB_MASK;
-	writel(calibval, (xrtcdev->reg_base + RTC_CALIB_WR));
+	xrtcdev->calibval &= RTC_CALIB_MASK;
+	writel(xrtcdev->calibval, (xrtcdev->reg_base + RTC_CALIB_WR));
 }
 
 static const struct rtc_class_ops xlnx_rtc_ops = {
@@ -150,11 +201,9 @@ static irqreturn_t xlnx_rtc_interrupt(int irq, void *id)
 	if (!(status & (RTC_INT_SEC | RTC_INT_ALRM)))
 		return IRQ_NONE;
 
-	/* Clear interrupt */
-	writel(status, xrtcdev->reg_base + RTC_INT_STS);
+	/* Clear RTC_INT_ALRM interrupt only */
+	writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_STS);
 
-	if (status & RTC_INT_SEC)
-		rtc_update_irq(xrtcdev->rtc, 1, RTC_IRQF | RTC_UF);
 	if (status & RTC_INT_ALRM)
 		rtc_update_irq(xrtcdev->rtc, 1, RTC_IRQF | RTC_AF);
 
@@ -166,7 +215,6 @@ static int xlnx_rtc_probe(struct platform_device *pdev)
 	struct xlnx_rtc_dev *xrtcdev;
 	struct resource *res;
 	int ret;
-	unsigned int calibvalue;
 
 	xrtcdev = devm_kzalloc(&pdev->dev, sizeof(*xrtcdev), GFP_KERNEL);
 	if (!xrtcdev)
@@ -207,11 +255,11 @@ static int xlnx_rtc_probe(struct platform_device *pdev)
 	}
 
 	ret = of_property_read_u32(pdev->dev.of_node, "calibration",
-				   &calibvalue);
+				   &xrtcdev->calibval);
 	if (ret)
-		calibvalue = RTC_CALIB_DEF;
+		xrtcdev->calibval = RTC_CALIB_DEF;
 
-	xlnx_init_rtc(xrtcdev, calibvalue);
+	xlnx_init_rtc(xrtcdev);
 
 	device_init_wakeup(&pdev->dev, 1);