File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/drivers/media/rc/ir-xmp-decoder.c b/drivers/media/rc/ir-xmp-decoder.c
new file mode 100644
index 0000000..1017d48
--- /dev/null
+++ b/drivers/media/rc/ir-xmp-decoder.c
@@ -0,0 +1,225 @@
+/* ir-xmp-decoder.c - handle XMP IR Pulse/Space protocol
+ *
+ * Copyright (C) 2014 by Marcel Mol
+ *
+ * This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation version 2 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ * - Based on info from http://www.hifi-remote.com
+ * - Ignore Toggle=9 frames
+ * - Ignore XMP-1 XMP-2 difference, always store 16 bit OBC
+ */
+
+#include <linux/bitrev.h>
+#include <linux/module.h>
+#include "rc-core-priv.h"
+
+#define XMP_UNIT		  136000 /* ns */
+#define XMP_LEADER		  210000 /* ns */
+#define XMP_NIBBLE_PREFIX	  760000 /* ns */
+#define	XMP_HALFFRAME_SPACE	13800000 /* ns */
+#define	XMP_TRAILER_SPACE	20000000 /* should be 80ms but not all dureation supliers can go that high */
+
+enum xmp_state {
+	STATE_INACTIVE,
+	STATE_LEADER_PULSE,
+	STATE_NIBBLE_SPACE,
+};
+
+/**
+ * ir_xmp_decode() - Decode one XMP pulse or space
+ * @dev:	the struct rc_dev descriptor of the device
+ * @duration:	the struct ir_raw_event descriptor of the pulse/space
+ *
+ * This function returns -EINVAL if the pulse violates the state machine
+ */
+static int ir_xmp_decode(struct rc_dev *dev, struct ir_raw_event ev)
+{
+	struct xmp_dec *data = &dev->raw->xmp;
+
+	if (!(dev->enabled_protocols & RC_BIT_XMP))
+		return 0;
+
+	if (!is_timing_event(ev)) {
+		if (ev.reset)
+			data->state = STATE_INACTIVE;
+		return 0;
+	}
+
+	IR_dprintk(2, "XMP decode started at state %d %d (%uus %s)\n",
+		   data->state, data->count, TO_US(ev.duration), TO_STR(ev.pulse));
+
+	switch (data->state) {
+
+	case STATE_INACTIVE:
+		if (!ev.pulse)
+			break;
+
+		if (eq_margin(ev.duration, XMP_LEADER, XMP_UNIT / 2)) {
+			data->count = 0;
+			data->state = STATE_NIBBLE_SPACE;
+		}
+
+		return 0;
+
+	case STATE_LEADER_PULSE:
+		if (!ev.pulse)
+			break;
+
+		if (eq_margin(ev.duration, XMP_LEADER, XMP_UNIT / 2))
+			data->state = STATE_NIBBLE_SPACE;
+
+		return 0;
+
+	case STATE_NIBBLE_SPACE:
+		if (ev.pulse)
+			break;
+
+		if (geq_margin(ev.duration, XMP_TRAILER_SPACE, XMP_NIBBLE_PREFIX)) {
+			int divider, i;
+			u8 addr, subaddr, subaddr2, toggle, oem, obc1, obc2, sum1, sum2;
+			u32 *n;
+			u32 scancode;
+
+			if (data->count != 16) {
+				IR_dprintk(2, "received TRAILER period at index %d: %u\n",
+					data->count, ev.duration);
+				data->state = STATE_INACTIVE;
+				return -EINVAL;
+			}
+
+			n = data->durations;
+			/*
+			 * the 4th nibble should be 15 so base the divider on this
+			 * to transform durations into nibbles. Substract 2000 from
+			 * the divider to compensate for fluctuations in the signal
+			 */
+			divider = (n[3] - XMP_NIBBLE_PREFIX) / 15 - 2000;
+			if (divider < 50) {
+				IR_dprintk(2, "divider to small %d.\n", divider);
+				data->state = STATE_INACTIVE;
+				return -EINVAL;
+			}
+
+			/* convert to nibbles and do some sanity checks */
+			for (i = 0; i < 16; i++)
+				n[i] = (n[i] - XMP_NIBBLE_PREFIX) / divider;
+			sum1 = (15 + n[0] + n[1] + n[2] + n[3] +
+				n[4] + n[5] + n[6] + n[7]) % 16;
+			sum2 = (15 + n[8] + n[9] + n[10] + n[11] +
+				n[12] + n[13] + n[14] + n[15]) % 16;
+
+			if (sum1 != 15 || sum2 != 15) {
+				IR_dprintk(2, "checksum errors sum1=0x%X sum2=0x%X\n",
+					sum1, sum2);
+				data->state = STATE_INACTIVE;
+				return -EINVAL;
+			}
+
+			subaddr  = n[0] << 4 | n[2];
+			subaddr2 = n[8] << 4 | n[11];
+			oem      = n[4] << 4 | n[5];
+			addr     = n[6] << 4 | n[7];
+			toggle   = n[10];
+			obc1 = n[12] << 4 | n[13];
+			obc2 = n[14] << 4 | n[15];
+			if (subaddr != subaddr2) {
+				IR_dprintk(2, "subaddress nibbles mismatch 0x%02X != 0x%02X\n",
+					subaddr, subaddr2);
+				data->state = STATE_INACTIVE;
+				return -EINVAL;
+			}
+			if (oem != 0x44)
+				IR_dprintk(1, "Warning: OEM nibbles 0x%02X. Expected 0x44\n",
+					oem);
+
+			scancode = addr << 24 | subaddr << 16 |
+				   obc1 << 8 | obc2;
+			IR_dprintk(1, "XMP scancode 0x%06x\n", scancode);
+
+			if (toggle == 0) {
+				rc_keydown(dev, RC_TYPE_XMP, scancode, 0);
+			} else {
+				rc_repeat(dev);
+				IR_dprintk(1, "Repeat last key\n");
+			}
+			data->state = STATE_INACTIVE;
+
+			return 0;
+
+		} else if (geq_margin(ev.duration, XMP_HALFFRAME_SPACE, XMP_NIBBLE_PREFIX)) {
+			/* Expect 8 or 16 nibble pulses. 16 in case of 'final' frame */
+			if (data->count == 16) {
+				IR_dprintk(2, "received half frame pulse at index %d. Probably a final frame key-up event: %u\n",
+					data->count, ev.duration);
+				/*
+				 * TODO: for now go back to half frame position
+				 *	 so trailer can be found and key press
+				 *	 can be handled.
+				 */
+				data->count = 8;
+			}
+
+			else if (data->count != 8)
+				IR_dprintk(2, "received half frame pulse at index %d: %u\n",
+					data->count, ev.duration);
+			data->state = STATE_LEADER_PULSE;
+
+			return 0;
+
+		} else if (geq_margin(ev.duration, XMP_NIBBLE_PREFIX, XMP_UNIT)) {
+			/* store nibble raw data, decode after trailer */
+			if (data->count == 16) {
+				IR_dprintk(2, "to many pulses (%d) ignoring: %u\n",
+					data->count, ev.duration);
+				data->state = STATE_INACTIVE;
+				return -EINVAL;
+			}
+			data->durations[data->count] = ev.duration;
+			data->count++;
+			data->state = STATE_LEADER_PULSE;
+
+			return 0;
+
+		}
+
+		break;
+	}
+
+	IR_dprintk(1, "XMP decode failed at count %d state %d (%uus %s)\n",
+		   data->count, data->state, TO_US(ev.duration), TO_STR(ev.pulse));
+	data->state = STATE_INACTIVE;
+	return -EINVAL;
+}
+
+static struct ir_raw_handler xmp_handler = {
+	.protocols	= RC_BIT_XMP,
+	.decode		= ir_xmp_decode,
+};
+
+static int __init ir_xmp_decode_init(void)
+{
+	ir_raw_handler_register(&xmp_handler);
+
+	printk(KERN_INFO "IR XMP protocol handler initialized\n");
+	return 0;
+}
+
+static void __exit ir_xmp_decode_exit(void)
+{
+	ir_raw_handler_unregister(&xmp_handler);
+}
+
+module_init(ir_xmp_decode_init);
+module_exit(ir_xmp_decode_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Marcel Mol <marcel@mesa.nl>");
+MODULE_AUTHOR("MESA Consulting (http://www.mesa.nl)");
+MODULE_DESCRIPTION("XMP IR protocol decoder");