[media] rc: img-ir: add philips rc6 decoder module

Add img-ir module for decoding Philips rc6 protocol.
Signed-off-by: Sifan Naeem <sifan.naeem@imgtec.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/rc/img-ir/Kconfig

@@ -67,3 +67,11 @@ config IR_IMG_RC5
 	help
 	   Say Y here to enable support for the RC5 protocol in the ImgTec
 	   infrared decoder block.
+
+config IR_IMG_RC6
+	bool "Philips RC6 protocol support"
+	depends on IR_IMG_HW
+	help
+	   Say Y here to enable support for the RC6 protocol in the ImgTec
+	   infrared decoder block.
+	   Note: This version only supports mode 0.

drivers/media/rc/img-ir/Makefile

@@ -7,6 +7,7 @@ img-ir-$(CONFIG_IR_IMG_SONY)	+= img-ir-sony.o
 img-ir-$(CONFIG_IR_IMG_SHARP)	+= img-ir-sharp.o
 img-ir-$(CONFIG_IR_IMG_SANYO)	+= img-ir-sanyo.o
 img-ir-$(CONFIG_IR_IMG_RC5)	+= img-ir-rc5.o
+img-ir-$(CONFIG_IR_IMG_RC6)	+= img-ir-rc6.o
 img-ir-objs			:= $(img-ir-y)
 
 obj-$(CONFIG_IR_IMG)		+= img-ir.o

drivers/media/rc/img-ir/img-ir-hw.c

@@ -44,6 +44,9 @@ static struct img_ir_decoder *img_ir_decoders[] = {
 #endif
 #ifdef CONFIG_IR_IMG_RC5
 	&img_ir_rc5,
+#endif
+#ifdef CONFIG_IR_IMG_RC6
+	&img_ir_rc6,
 #endif
 	NULL
 };

drivers/media/rc/img-ir/img-ir-hw.h

@@ -188,6 +188,7 @@ extern struct img_ir_decoder img_ir_sony;
 extern struct img_ir_decoder img_ir_sharp;
 extern struct img_ir_decoder img_ir_sanyo;
 extern struct img_ir_decoder img_ir_rc5;
+extern struct img_ir_decoder img_ir_rc6;
 
 /**
  * struct img_ir_reg_timings - Reg values for decoder timings at clock rate.

drivers/media/rc/img-ir/img-ir-rc6.c

+/*
+ * ImgTec IR Decoder setup for Philips RC-6 protocol.
+ *
+ * Copyright 2012-2014 Imagination Technologies Ltd.
+ *
+ * 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; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include "img-ir-hw.h"
+
+/* Convert RC6 data to a scancode */
+static int img_ir_rc6_scancode(int len, u64 raw, u64 enabled_protocols,
+				struct img_ir_scancode_req *request)
+{
+	unsigned int addr, cmd, mode, trl1, trl2;
+
+	/*
+	 * Due to a side effect of the decoder handling the double length
+	 * Trailer bit, the header information is a bit scrambled, and the
+	 * raw data is shifted incorrectly.
+	 * This workaround effectively recovers the header bits.
+	 *
+	 * The Header field should look like this:
+	 *
+	 * StartBit ModeBit2 ModeBit1 ModeBit0 TrailerBit
+	 *
+	 * But what we get is:
+	 *
+	 * ModeBit2 ModeBit1 ModeBit0 TrailerBit1 TrailerBit2
+	 *
+	 * The start bit is not important to recover the scancode.
+	 */
+
+	raw	>>= 27;
+
+	trl1	= (raw >>  17)	& 0x01;
+	trl2	= (raw >>  16)	& 0x01;
+
+	mode	= (raw >>  18)	& 0x07;
+	addr	= (raw >>   8)	& 0xff;
+	cmd	=  raw		& 0xff;
+
+	/*
+	 * Due to the above explained irregularity the trailer bits cannot
+	 * have the same value.
+	 */
+	if (trl1 == trl2)
+		return -EINVAL;
+
+	/* Only mode 0 supported for now */
+	if (mode)
+		return -EINVAL;
+
+	request->protocol = RC_TYPE_RC6_0;
+	request->scancode = addr << 8 | cmd;
+	request->toggle	  = trl2;
+	return IMG_IR_SCANCODE;
+}
+
+/* Convert RC6 scancode to RC6 data filter */
+static int img_ir_rc6_filter(const struct rc_scancode_filter *in,
+				 struct img_ir_filter *out, u64 protocols)
+{
+	/* Not supported by the hw. */
+	return -EINVAL;
+}
+
+/*
+ * RC-6 decoder
+ * see http://www.sbprojects.com/knowledge/ir/rc6.php
+ */
+struct img_ir_decoder img_ir_rc6 = {
+	.type		= RC_BIT_RC6_0,
+	.control	= {
+		.bitorien	= 1,
+		.code_type	= IMG_IR_CODETYPE_BIPHASE,
+		.decoden	= 1,
+		.decodinpol	= 1,
+	},
+	/* main timings */
+	.tolerance	= 20,
+	/*
+	 * Due to a quirk in the img-ir decoder, default header values do
+	 * not work, the values described below were extracted from
+	 * successful RTL test cases.
+	 */
+	.timings	= {
+		/* leader symbol */
+		.ldr = {
+			.pulse	= { 650 },
+			.space	= { 660 },
+		},
+		/* 0 symbol */
+		.s00 = {
+			.pulse	= { 370 },
+			.space	= { 370 },
+		},
+		/* 01 symbol */
+		.s01 = {
+			.pulse	= { 370 },
+			.space	= { 370 },
+		},
+		/* free time */
+		.ft  = {
+			.minlen = 21,
+			.maxlen = 21,
+			.ft_min = 2666,	/* 2.666 ms */
+		},
+	},
+
+	/* scancode logic */
+	.scancode	= img_ir_rc6_scancode,
+	.filter		= img_ir_rc6_filter,
+};