[PATCH 3/3] drivers/rtc/rtc-snvs: Add clock support

[maitysanchayan@gmail.com (Sanchayan Maity)]

This patch adds clock enable and disable support
for the SNVS peripheral which is required by the
SNVS RTC.

Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
---
 drivers/rtc/rtc-snvs.c |   48 +++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 39 insertions(+), 9 deletions(-)

diff --git a/drivers/rtc/rtc-snvs.c b/drivers/rtc/rtc-snvs.c
index fa384fe..f3e8f05 100644
--- a/drivers/rtc/rtc-snvs.c
+++ b/drivers/rtc/rtc-snvs.c
@@ -17,6 +17,7 @@
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/rtc.h>
+#include <linux/clk.h>
 
 /* These register offsets are relative to LP (Low Power) range */
 #define SNVS_LPCR		0x04
@@ -39,6 +40,7 @@ struct snvs_rtc_data {
 	void __iomem *ioaddr;
 	int irq;
 	spinlock_t lock;
+	struct clk *clk;
 };
 
 static u32 rtc_read_lp_counter(void __iomem *ioaddr)
@@ -260,8 +262,31 @@ static int snvs_rtc_probe(struct platform_device *pdev)
 	if (data->irq < 0)
 		return data->irq;
 
+	ret = devm_request_irq(&pdev->dev, data->irq, snvs_rtc_irq_handler,
+			       IRQF_SHARED, "rtc alarm", &pdev->dev);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to request irq %d: %d\n",
+			data->irq, ret);
+		return ret;
+	}
+
+	data->clk = devm_clk_get(&pdev->dev, "snvs");
+	if (IS_ERR(data->clk)) {
+		dev_err(&pdev->dev, "failed getting clock, err = %ld\n",
+						PTR_ERR(data->clk));
+		ret = PTR_ERR(data->clk);
+		return ret;
+	}
+
 	platform_set_drvdata(pdev, data);
 
+	ret = clk_prepare_enable(data->clk);
+	if (ret) {
+		dev_err(&pdev->dev,
+			"Could not prepare or enable the snvs clock\n");
+		return ret;
+	}
+
 	spin_lock_init(&data->lock);
 
 	/* Initialize glitch detect */
@@ -275,23 +300,20 @@ static int snvs_rtc_probe(struct platform_device *pdev)
 
 	device_init_wakeup(&pdev->dev, true);
 
-	ret = devm_request_irq(&pdev->dev, data->irq, snvs_rtc_irq_handler,
-			       IRQF_SHARED, "rtc alarm", &pdev->dev);
-	if (ret) {
-		dev_err(&pdev->dev, "failed to request irq %d: %d\n",
-			data->irq, ret);
-		return ret;
-	}
-
 	data->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 					&snvs_rtc_ops, THIS_MODULE);
 	if (IS_ERR(data->rtc)) {
 		ret = PTR_ERR(data->rtc);
 		dev_err(&pdev->dev, "failed to register rtc: %d\n", ret);
-		return ret;
+		goto error_rtc_device_register;
 	}
 
 	return 0;
+
+error_rtc_device_register:
+	clk_disable_unprepare(data->clk);
+
+	return ret;
 }
 
 #ifdef CONFIG_PM_SLEEP
@@ -302,16 +324,24 @@ static int snvs_rtc_suspend(struct device *dev)
 	if (device_may_wakeup(dev))
 		enable_irq_wake(data->irq);
 
+	clk_disable_unprepare(data->clk);
+
 	return 0;
 }
 
 static int snvs_rtc_resume(struct device *dev)
 {
+	int ret;
+
 	struct snvs_rtc_data *data = dev_get_drvdata(dev);
 
 	if (device_may_wakeup(dev))
 		disable_irq_wake(data->irq);
 
+	ret = clk_prepare_enable(data->clk);
+	if (ret)
+		return ret;
+
 	return 0;
 }
 #endif
-- 
1.7.9.5