[media] rc: img-ir: add NEC decoder module

Add an img-ir module for decoding the NEC and extended NEC infrared
protocols.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/rc/img-ir/Kconfig

@@ -24,3 +24,10 @@ config IR_IMG_HW
 	   signals in hardware. This is more reliable, consumes less processing
 	   power since only a single interrupt is received for each scancode,
 	   and allows an IR scancode to be used as a wake event.
+
+config IR_IMG_NEC
+	bool "NEC protocol support"
+	depends on IR_IMG_HW
+	help
+	   Say Y here to enable support for the NEC, extended NEC, and 32-bit
+	   NEC protocols in the ImgTec infrared decoder block.

drivers/media/rc/img-ir/Makefile

@@ -1,6 +1,7 @@
 img-ir-y			:= img-ir-core.o
 img-ir-$(CONFIG_IR_IMG_RAW)	+= img-ir-raw.o
 img-ir-$(CONFIG_IR_IMG_HW)	+= img-ir-hw.o
+img-ir-$(CONFIG_IR_IMG_NEC)	+= img-ir-nec.o
 img-ir-objs			:= $(img-ir-y)
 
 obj-$(CONFIG_IR_IMG)		+= img-ir.o

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

@@ -20,8 +20,13 @@
 /* Decoders lock (only modified to preprocess them) */
 static DEFINE_SPINLOCK(img_ir_decoders_lock);
 
+extern struct img_ir_decoder img_ir_nec;
+
 static bool img_ir_decoders_preprocessed;
 static struct img_ir_decoder *img_ir_decoders[] = {
+#ifdef CONFIG_IR_IMG_NEC
+	&img_ir_nec,
+#endif
 	NULL
 };
 

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

@@ -0,0 +1,148 @@
+/*
+ * ImgTec IR Decoder setup for NEC protocol.
+ *
+ * Copyright 2010-2014 Imagination Technologies Ltd.
+ */
+
+#include "img-ir-hw.h"
+
+/* Convert NEC data to a scancode */
+static int img_ir_nec_scancode(int len, u64 raw, int *scancode, u64 protocols)
+{
+	unsigned int addr, addr_inv, data, data_inv;
+	/* a repeat code has no data */
+	if (!len)
+		return IMG_IR_REPEATCODE;
+	if (len != 32)
+		return -EINVAL;
+	/* raw encoding: ddDDaaAA */
+	addr     = (raw >>  0) & 0xff;
+	addr_inv = (raw >>  8) & 0xff;
+	data     = (raw >> 16) & 0xff;
+	data_inv = (raw >> 24) & 0xff;
+	if ((data_inv ^ data) != 0xff) {
+		/* 32-bit NEC (used by Apple and TiVo remotes) */
+		/* scan encoding: aaAAddDD */
+		*scancode = addr_inv << 24 |
+			    addr     << 16 |
+			    data_inv <<  8 |
+			    data;
+	} else if ((addr_inv ^ addr) != 0xff) {
+		/* Extended NEC */
+		/* scan encoding: AAaaDD */
+		*scancode = addr     << 16 |
+			    addr_inv <<  8 |
+			    data;
+	} else {
+		/* Normal NEC */
+		/* scan encoding: AADD */
+		*scancode = addr << 8 |
+			    data;
+	}
+	return IMG_IR_SCANCODE;
+}
+
+/* Convert NEC scancode to NEC data filter */
+static int img_ir_nec_filter(const struct rc_scancode_filter *in,
+			     struct img_ir_filter *out, u64 protocols)
+{
+	unsigned int addr, addr_inv, data, data_inv;
+	unsigned int addr_m, addr_inv_m, data_m, data_inv_m;
+
+	data       = in->data & 0xff;
+	data_m     = in->mask & 0xff;
+
+	if ((in->data | in->mask) & 0xff000000) {
+		/* 32-bit NEC (used by Apple and TiVo remotes) */
+		/* scan encoding: aaAAddDD */
+		addr_inv   = (in->data >> 24) & 0xff;
+		addr_inv_m = (in->mask >> 24) & 0xff;
+		addr       = (in->data >> 16) & 0xff;
+		addr_m     = (in->mask >> 16) & 0xff;
+		data_inv   = (in->data >>  8) & 0xff;
+		data_inv_m = (in->mask >>  8) & 0xff;
+	} else if ((in->data | in->mask) & 0x00ff0000) {
+		/* Extended NEC */
+		/* scan encoding AAaaDD */
+		addr       = (in->data >> 16) & 0xff;
+		addr_m     = (in->mask >> 16) & 0xff;
+		addr_inv   = (in->data >>  8) & 0xff;
+		addr_inv_m = (in->mask >>  8) & 0xff;
+		data_inv   = data ^ 0xff;
+		data_inv_m = data_m;
+	} else {
+		/* Normal NEC */
+		/* scan encoding: AADD */
+		addr       = (in->data >>  8) & 0xff;
+		addr_m     = (in->mask >>  8) & 0xff;
+		addr_inv   = addr ^ 0xff;
+		addr_inv_m = addr_m;
+		data_inv   = data ^ 0xff;
+		data_inv_m = data_m;
+	}
+
+	/* raw encoding: ddDDaaAA */
+	out->data = data_inv << 24 |
+		    data     << 16 |
+		    addr_inv <<  8 |
+		    addr;
+	out->mask = data_inv_m << 24 |
+		    data_m     << 16 |
+		    addr_inv_m <<  8 |
+		    addr_m;
+	return 0;
+}
+
+/*
+ * NEC decoder
+ * See also http://www.sbprojects.com/knowledge/ir/nec.php
+ *        http://wiki.altium.com/display/ADOH/NEC+Infrared+Transmission+Protocol
+ */
+struct img_ir_decoder img_ir_nec = {
+	.type = RC_BIT_NEC,
+	.control = {
+		.decoden = 1,
+		.code_type = IMG_IR_CODETYPE_PULSEDIST,
+	},
+	/* main timings */
+	.unit = 562500, /* 562.5 us */
+	.timings = {
+		/* leader symbol */
+		.ldr = {
+			.pulse = { 16	/* 9ms */ },
+			.space = { 8	/* 4.5ms */ },
+		},
+		/* 0 symbol */
+		.s00 = {
+			.pulse = { 1	/* 562.5 us */ },
+			.space = { 1	/* 562.5 us */ },
+		},
+		/* 1 symbol */
+		.s01 = {
+			.pulse = { 1	/* 562.5 us */ },
+			.space = { 3	/* 1687.5 us */ },
+		},
+		/* free time */
+		.ft = {
+			.minlen = 32,
+			.maxlen = 32,
+			.ft_min = 10,	/* 5.625 ms */
+		},
+	},
+	/* repeat codes */
+	.repeat = 108,			/* 108 ms */
+	.rtimings = {
+		/* leader symbol */
+		.ldr = {
+			.space = { 4	/* 2.25 ms */ },
+		},
+		/* free time */
+		.ft = {
+			.minlen = 0,	/* repeat code has no data */
+			.maxlen = 0,
+		},
+	},
+	/* scancode logic */
+	.scancode = img_ir_nec_scancode,
+	.filter = img_ir_nec_filter,
+};