Input: nomadik-ske-keypad - get rid of multiple interrupts

The keypad could cause multiple interrupts to be fired in succession
since we weren't waiting for the IRQs to clear properly in the
interrupt handler. We wait for a number of bus iterations (the
readl():s from the peripheral bus will stall, so these are quite
long) before giving up on getting keys ready to read, then we
sleep until the IRQ is deasserted (this is OK since the interrupt
is threaded). Also use the debounce platform data for another
hardcoded wait loop.

Signed-off-by: Naveen Kumar Gaddipati <[e-mail]>
Reviewed-by: Rikard Olsson <[e-mail]>
Reviewed-by: Srinidhi Kasagar <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/keyboard/nomadik-ske-keypad.c

···
 #define SKE_ASR3	0x2C
 
 #define SKE_NUM_ASRX_REGISTERS	(4)
+#define	KEY_PRESSED_DELAY	10
 
 /**
  * struct ske_keypad  - data structure used by keypad driver
···
 static int __init ske_keypad_chip_init(struct ske_keypad *keypad)
 {
 	u32 value;
-	int timeout = 50;
+	int timeout = keypad->board->debounce_ms;
 
 	/* check SKE_RIS to be 0 */
 	while ((readl(keypad->reg_base + SKE_RIS) != 0x00000000) && timeout--)
···
 static irqreturn_t ske_keypad_irq(int irq, void *dev_id)
 {
 	struct ske_keypad *keypad = dev_id;
-	int retries = 20;
+	int timeout = keypad->board->debounce_ms;
 
 	/* disable auto scan interrupt; mask the interrupt generated */
 	ske_keypad_set_bits(keypad, SKE_IMSC, ~SKE_KPIMA, 0x0);
 	ske_keypad_set_bits(keypad, SKE_ICR, 0x0, SKE_KPICA);
 
-	while ((readl(keypad->reg_base + SKE_CR) & SKE_KPASON) && --retries)
+	while ((readl(keypad->reg_base + SKE_CR) & SKE_KPASON) && --timeout)
 		cpu_relax();
 
 	/* SKEx registers are stable and can be read */
 	ske_keypad_read_data(keypad);
+
+	/* wait until raw interrupt is clear */
+	while ((readl(keypad->reg_base + SKE_RIS)) && --timeout)
+		msleep(KEY_PRESSED_DELAY);
 
 	/* enable auto scan interrupts */
 	ske_keypad_set_bits(keypad, SKE_IMSC, 0x0, SKE_KPIMA);