Input: imx_keypad - reset the hardware before enabling

Ensure the hardware is correctly initialized before requesting the
interrupt, otherwise if a key was already touched since power-on the
kernel enters an interrupt loop. To fix this issue we clear pending
interrupt sources. We also have to make sure clk is enabled while
changing the keypad registers.
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/keyboard/imx_keypad.c

@@ -358,6 +358,7 @@ static void imx_keypad_inhibit(struct imx_keypad *keypad)
 	/* Inhibit KDI and KRI interrupts. */
 	reg_val = readw(keypad->mmio_base + KPSR);
 	reg_val &= ~(KBD_STAT_KRIE | KBD_STAT_KDIE);
+	reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD;
 	writew(reg_val, keypad->mmio_base + KPSR);
 
 	/* Colums as open drain and disable all rows */
@@ -515,7 +516,9 @@ static int __devinit imx_keypad_probe(struct platform_device *pdev)
 	input_set_drvdata(input_dev, keypad);
 
 	/* Ensure that the keypad will stay dormant until opened */
+	clk_enable(keypad->clk);
 	imx_keypad_inhibit(keypad);
+	clk_disable(keypad->clk);
 
 	error = request_irq(irq, imx_keypad_irq_handler, 0,
 			    pdev->name, keypad);