[PATCH 2/3] Input: samsung-keypad - keep interrupt disabled while closed

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

The driver requests the interrupt during probe, which by default enables
it. If the bootloader left the keypad interrupts enabled, or if a
spurious interrupt fires early before the driver is fully initialized
and clocks are enabled, the interrupt handler will attempt to read
registers and may cause a synchronous external abort.

Fix this by requesting the interrupt with IRQF_NO_AUTOEN, keeping it
disabled during probe. Enable the interrupt in samsung_keypad_start()
when the device is opened and ready, and disable it in
samsung_keypad_stop() when the device is closed. Remove the redundant
re-enabling of the interrupt at the end of samsung_keypad_stop().

Additionally, manually clear the pending interrupt status during system
resume when the device is closed to avoid immediate resume.

Fixes: 0fffed27f92d ("Input: samsung-keypad - Add samsung keypad driver")
Assisted-by: Antigravity:gemini-3.1-pro
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/keyboard/samsung-keypad.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/input/keyboard/samsung-keypad.c b/drivers/input/keyboard/samsung-keypad.c
index a578f429d100..88e733c1eabe 100644
--- a/drivers/input/keyboard/samsung-keypad.c
+++ b/drivers/input/keyboard/samsung-keypad.c
@@ -183,6 +183,8 @@ static void samsung_keypad_start(struct samsung_keypad *keypad)
 	writel(0, keypad->base + SAMSUNG_KEYIFCOL);
 
 	pm_runtime_put(&keypad->pdev->dev);
+
+	enable_irq(keypad->irq);
 }
 
 static void samsung_keypad_stop(struct samsung_keypad *keypad)
@@ -206,12 +208,6 @@ static void samsung_keypad_stop(struct samsung_keypad *keypad)
 
 	clk_disable(keypad->clk);
 
-	/*
-	 * Now that chip should not generate interrupts we can safely
-	 * re-enable the handler.
-	 */
-	enable_irq(keypad->irq);
-
 	pm_runtime_put(&keypad->pdev->dev);
 }
 
@@ -412,7 +408,8 @@ static int samsung_keypad_probe(struct platform_device *pdev)
 	}
 
 	error = devm_request_threaded_irq(&pdev->dev, keypad->irq, NULL,
-					  samsung_keypad_irq, IRQF_ONESHOT,
+					  samsung_keypad_irq,
+					  IRQF_ONESHOT | IRQF_NO_AUTOEN,
 					  dev_name(&pdev->dev), keypad);
 	if (error) {
 		dev_err(&pdev->dev, "failed to register keypad interrupt\n");
@@ -499,6 +496,9 @@ static void samsung_keypad_toggle_wakeup(struct samsung_keypad *keypad,
 		val &= ~SAMSUNG_KEYIFCON_WAKEUPEN;
 		writel(val, keypad->base + SAMSUNG_KEYIFCON);
 		disable_irq_wake(keypad->irq);
+
+		if (keypad->stopped)
+			writel(~0x0, keypad->base + SAMSUNG_KEYIFSTSCLR);
 	}
 
 	clk_disable(keypad->clk);
-- 
2.55.0.795.g602f6c329a-goog