Enable keypress interrupt to support wakeup from low power state.

Signed-off-by: Rakesh Iyer <redacted>
---
 drivers/input/keyboard/tegra-kbc.c |   17 +++++++++++++++++
 1 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/drivers/input/keyboard/tegra-kbc.c b/drivers/input/keyboard/tegra-kbc.c
index a136e2e..b307a46 100644
--- a/drivers/input/keyboard/tegra-kbc.c
+++ b/drivers/input/keyboard/tegra-kbc.c

@@ -48,6 +48,7 @@
 #define KBC_FIFO_TH_CNT_SHIFT(cnt)	(cnt << 14)
 #define KBC_DEBOUNCE_CNT_SHIFT(cnt)	(cnt << 4)
 #define KBC_CONTROL_FIFO_CNT_INT_EN	(1 << 3)
+#define KBC_CONTROL_KEYPRESS_INT_EN	(1 << 1)
 #define KBC_CONTROL_KBC_EN		(1 << 0)
 
 /* KBC Interrupt Register */

@@ -356,6 +357,18 @@ static void tegra_kbc_set_fifo_interrupt(struct tegra_kbc *kbc, bool enable)
 	writel(val, kbc->mmio + KBC_CONTROL_0);
 }
 
+static void tegra_kbc_set_keypress_interrupt(struct tegra_kbc *kbc, bool enable)
+{
+	u32 val;
+
+	val = readl(kbc->mmio + KBC_CONTROL_0);
+	if (enable)
+		val |= KBC_CONTROL_KEYPRESS_INT_EN;
+	else
+		val &= ~KBC_CONTROL_KEYPRESS_INT_EN;
+	writel(val, kbc->mmio + KBC_CONTROL_0);
+}
+
 static void tegra_kbc_keypress_timer(unsigned long data)
 {
 	struct tegra_kbc *kbc = (struct tegra_kbc *)data;

@@ -831,6 +844,8 @@ static int tegra_kbc_suspend(struct device *dev)
 		msleep(30);
 
 		kbc->keypress_caused_wake = false;
+		/* Enable keypress interrupt before going into suspend. */
+		tegra_kbc_set_keypress_interrupt(kbc, true);
 		enable_irq(kbc->irq);
 		enable_irq_wake(kbc->irq);
 	} else {

@@ -852,6 +867,8 @@ static int tegra_kbc_resume(struct device *dev)
 	if (device_may_wakeup(&pdev->dev)) {
 		disable_irq_wake(kbc->irq);
 		tegra_kbc_setup_wakekeys(kbc, false);
+		/* We will use fifo interrupts for key detection. */
+		tegra_kbc_set_keypress_interrupt(kbc, false);