V4L/DVB (5246): Budget-ci: IR handling fixups

Commit 00c4cc67 Oliver Endriss changed 
the budget-ci driver to use interrupt mode for i2c transfers.

This also meant that a new bunch of IR bytes that were previously lost 
are now received, which allowed me to better understand how the MSP430 
chip works. Unfortunately it also means that the current driver gets 
some assumptions wrong and might generate double keypresses for one IR 
command. 

The attached patch fixes this by throwing away the repeat bytes and by 
associating the correct command and device bytes.
Signed-off-by: David Härdeman <david@hardeman.nu>
Signed-off-by: Oliver Endriss <o.endriss@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/dvb/ttpci/budget-ci.c

@@ -130,6 +130,7 @@ static void msp430_ir_interrupt(unsigned long data)
 	int toggle;
 	static int prev_toggle = -1;
 	static u32 ir_key;
+	static int state = 0;
 	u32 command = ttpci_budget_debiread(&budget_ci->budget, DEBINOSWAP, DEBIADDR_IR, 2, 1, 0) >> 8;
 
 	/*
@@ -138,21 +139,34 @@ static void msp430_ir_interrupt(unsigned long data)
 	 * type1: X1CCCCCC, C = command bits (0 - 63)
 	 * type2: X0TDDDDD, D = device bits (0 - 31), T = RC5 toggle bit
 	 *
-	 * More than one command byte may be generated before the device byte
-	 * Only when we have both, a correct keypress is generated
+	 * Each signal from the remote control can generate one or more command
+	 * bytes and one or more device bytes. For the repeated bytes, the
+	 * highest bit (X) is set. The first command byte is always generated
+	 * before the first device byte. Other than that, no specific order
+	 * seems to apply.
+	 *
+	 * Only when we have a command and device byte, a keypress is
+	 * generated.
 	 */
 
+	if (ir_debug)
+		printk("budget_ci: received byte 0x%02x\n", command);
+
+	/* Is this a repeated byte? */
+	if (command & 0x80)
+		return;
+
 	/* Is this a RC5 command byte? */
 	if (command & 0x40) {
-		if (ir_debug)
-			printk("budget_ci: received command byte 0x%02x\n", command);
+		state = 1;
 		ir_key = command & 0x3f;
 		return;
 	}
 
 	/* It's a RC5 device byte */
-	if (ir_debug)
-		printk("budget_ci: received device byte 0x%02x\n", command);
+	if (!state)
+		return;
+	state = 0;
 	device = command & 0x1f;
 	toggle = command & 0x20;