Input: pxa27x_keypad keep clock on as wakeup source

When the keypad is used as wake up source, the clock can not
be disabled. Or it can not detect key pressing.
If the keypad is used as wake up source, when resume back,
do not enable the clock and configure it again because the
register content is retained.

Signed-off-by: Chao Xie <chao.xie@marvell.com>
Signed-off-by: Haojian Zhuang <haojian.zhuang@gmail.com>
diff --git a/drivers/input/keyboard/pxa27x_keypad.c b/drivers/input/keyboard/pxa27x_keypad.c
index 29fe1b2..b07771e 100644
--- a/drivers/input/keyboard/pxa27x_keypad.c
+++ b/drivers/input/keyboard/pxa27x_keypad.c
@@ -399,7 +399,7 @@
 	struct pxa27x_keypad *keypad = input_get_drvdata(dev);
 
 	/* Enable unit clock */
-	clk_enable(keypad->clk);
+	clk_prepare_enable(keypad->clk);
 	pxa27x_keypad_config(keypad);
 
 	return 0;
@@ -410,7 +410,7 @@
 	struct pxa27x_keypad *keypad = input_get_drvdata(dev);
 
 	/* Disable clock unit */
-	clk_disable(keypad->clk);
+	clk_disable_unprepare(keypad->clk);
 }
 
 #ifdef CONFIG_PM
@@ -419,10 +419,14 @@
 	struct platform_device *pdev = to_platform_device(dev);
 	struct pxa27x_keypad *keypad = platform_get_drvdata(pdev);
 
-	clk_disable(keypad->clk);
-
+	/*
+	 * If the keypad is used a wake up source, clock can not be disabled.
+	 * Or it can not detect the key pressing.
+	 */
 	if (device_may_wakeup(&pdev->dev))
 		enable_irq_wake(keypad->irq);
+	else
+		clk_disable_unprepare(keypad->clk);
 
 	return 0;
 }
@@ -433,19 +437,24 @@
 	struct pxa27x_keypad *keypad = platform_get_drvdata(pdev);
 	struct input_dev *input_dev = keypad->input_dev;
 
-	if (device_may_wakeup(&pdev->dev))
+	/*
+	 * If the keypad is used as wake up source, the clock is not turned
+	 * off. So do not need configure it again.
+	 */
+	if (device_may_wakeup(&pdev->dev)) {
 		disable_irq_wake(keypad->irq);
+	} else {
+		mutex_lock(&input_dev->mutex);
 
-	mutex_lock(&input_dev->mutex);
+		if (input_dev->users) {
+			/* Enable unit clock */
+			clk_prepare_enable(keypad->clk);
+			pxa27x_keypad_config(keypad);
+		}
 
-	if (input_dev->users) {
-		/* Enable unit clock */
-		clk_enable(keypad->clk);
-		pxa27x_keypad_config(keypad);
+		mutex_unlock(&input_dev->mutex);
 	}
 
-	mutex_unlock(&input_dev->mutex);
-
 	return 0;
 }