ir-core: one-line bugfix, add RC5x, NECx, RC6

When I converted drivers/media/dvb/ttpci/budget-ci.c to use ir-core I missed one line. This patch fixes that mistake.

Signed-off-by David Härdeman <[email protected]>

---
 drivers/media/dvb/ttpci/budget-ci.c |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)

drivers/media/dvb/ttpci/budget-ci.c +0 -2

index 8950df1..4617143 100644
@@ -225,8 +225,6 @@ static int msp430_ir_init(struct budget_ci *budget_ci)
 		break;
 	}
 
-	ir_input_init(input_dev, &budget_ci->ir.state, IR_TYPE_RC5);
-
 	error = ir_input_register(input_dev, ir_codes, NULL, MODULE_NAME);
 	if (error) {
 		printk(KERN_ERR "budget_ci: could not init driver for IR device (code %d)\n", error);

drivers/media/IR/ir-core-priv.h +0 -0

@@ -109,4 +109,11 @@ void ir_raw_init(void);
 #define load_rc5_decode()	0

drivers/media/IR/ir-core-priv.h void ir_raw_init(void); · line 113

Quoted 2 lines

drivers/media/IR/ir-core-priv.h +2 -0

+/* from ir-rc6-decoder.c */
+#ifdef CONFIG_IR_RC5_DECODER_MODULE

you probably intended to use CONFIG_IR_RC6_DECODER_MODULE instead.

Quoted 3 lines · Andreas Oberritter

drivers/media/IR/ir-core-priv.h void ir_raw_init(void); · line 113

Quoted 2 lines

drivers/media/IR/ir-core-priv.h +2 -0

+/* from ir-rc6-decoder.c */
+#ifdef CONFIG_IR_RC5_DECODER_MODULE

you probably intended to use CONFIG_IR_RC6_DECODER_MODULE instead.

Of course, thanks for noticing.

Mauro, do you want a new patch or will you fix it yourself?

(and by the
way, Mauro, how come the patches went straight to the v4l-dvb.git tree? I assume they'll be merged back to your ir.git tree at a later stage?)

This patch adds an RC6 decoder (modes 0 and 6A) to ir-core.

Signed-off-by David Härdeman <[email protected]>

---
 drivers/media/IR/Kconfig          |    9 +
 drivers/media/IR/Makefile         |    1 
 drivers/media/IR/ir-core-priv.h   |    7 +
 drivers/media/IR/ir-raw-event.c   |    1 
 drivers/media/IR/ir-rc6-decoder.c |  412 +++++++++++++++++++++++++++++++++++++
 drivers/media/IR/ir-sysfs.c       |    2 
 include/media/rc-map.h            |    1 
 7 files changed, 433 insertions(+), 0 deletions(-)
 create mode 100644 drivers/media/IR/ir-rc6-decoder.c

drivers/media/IR/Kconfig +9 -0

index ba81bda..28d336d 100644
@@ -27,3 +27,12 @@ config IR_RC5_DECODER
 	---help---
 	   Enable this option if you have IR with RC-5 protocol, and
 	   if the IR is decoded in software
+
+config IR_RC6_DECODER
+	tristate "Enable IR raw decoder for the RC6 protocol"
+	depends on IR_CORE
+	default y
+
+	---help---
+	   Enable this option if you have an infrared remote control which
+	   uses the RC6 protocol, and you need software decoding support.

drivers/media/IR/Makefile +1 -0

index 62e12d5..792d9ca 100644
@@ -7,3 +7,4 @@ obj-$(CONFIG_IR_CORE) += ir-core.o
 obj-$(CONFIG_VIDEO_IR) += ir-common.o
 obj-$(CONFIG_IR_NEC_DECODER) += ir-nec-decoder.o
 obj-$(CONFIG_IR_RC5_DECODER) += ir-rc5-decoder.o
+obj-$(CONFIG_IR_RC6_DECODER) += ir-rc6-decoder.o

drivers/media/IR/ir-core-priv.h +7 -0

index ab785bc..853ec80 100644
@@ -109,4 +109,11 @@ void ir_raw_init(void);
 #define load_rc5_decode()	0
 #endif
 
+/* from ir-rc6-decoder.c */
+#ifdef CONFIG_IR_RC5_DECODER_MODULE
+#define load_rc6_decode()	request_module("ir-rc6-decoder")
+#else
+#define load_rc6_decode()	0
+#endif
+
 #endif /* _IR_RAW_EVENT */

drivers/media/IR/ir-raw-event.c +1 -0

index 2efc051..ef0f231 100644
@@ -224,6 +224,7 @@ static void init_decoders(struct work_struct *work)
 
 	load_nec_decode();
 	load_rc5_decode();
+	load_rc6_decode();
 
 	/* If needed, we may later add some init code. In this case,
 	   it is needed to change the CONFIG_MODULE test at ir-core.h

drivers/media/IR/ir-rc6-decoder.c new file +12 -0

new file mode 100644
index 0000000..ccc5be2
@@ -0,0 +1,412 @@
+/* ir-rc6-decoder.c - A decoder for the RC6 IR protocol
+ *
+ * Copyright (C) 2010 by David Härdeman <[email protected]>
+ *
+ * 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.

drivers/media/IR/ir-rc6-decoder.c new file +145 -0

+
+/* Used to register rc6_decoder clients */
+static LIST_HEAD(decoder_list);
+static DEFINE_SPINLOCK(decoder_lock);
+
+enum rc6_mode {
+	RC6_MODE_0,
+	RC6_MODE_6A,
+	RC6_MODE_UNKNOWN,
+};
+
+enum rc6_state {
+	STATE_INACTIVE,
+	STATE_PREFIX_SPACE,
+	STATE_HEADER_BIT_START,
+	STATE_HEADER_BIT_END,
+	STATE_TOGGLE_START,
+	STATE_TOGGLE_END,
+	STATE_BODY_BIT_START,
+	STATE_BODY_BIT_END,
+	STATE_FINISHED,
+};
+
+struct decoder_data {
+	struct list_head	list;
+	struct ir_input_dev	*ir_dev;
+	int			enabled:1;
+
+	/* State machine control */
+	enum rc6_state		state;
+	u8			header;
+	u32			body;
+	int			last_unit;
+	bool			toggle;
+	unsigned		count;
+	unsigned		wanted_bits;
+};
+
+
+/**
+ * get_decoder_data()	- gets decoder data
+ * @input_dev:	input device
+ *
+ * Returns the struct decoder_data that corresponds to a device
+ */
+static struct decoder_data *get_decoder_data(struct  ir_input_dev *ir_dev)
+{
+	struct decoder_data *data = NULL;
+
+	spin_lock(&decoder_lock);
+	list_for_each_entry(data, &decoder_list, list) {
+		if (data->ir_dev == ir_dev)
+			break;
+	}
+	spin_unlock(&decoder_lock);
+	return data;
+}
+
+static ssize_t store_enabled(struct device *d,
+			     struct device_attribute *mattr,
+			     const char *buf,
+			     size_t len)
+{
+	unsigned long value;
+	struct ir_input_dev *ir_dev = dev_get_drvdata(d);
+	struct decoder_data *data = get_decoder_data(ir_dev);
+
+	if (!data)
+		return -EINVAL;
+
+	if (strict_strtoul(buf, 10, &value) || value > 1)
+		return -EINVAL;
+
+	data->enabled = value;
+
+	return len;
+}
+
+static ssize_t show_enabled(struct device *d,
+			     struct device_attribute *mattr, char *buf)
+{
+	struct ir_input_dev *ir_dev = dev_get_drvdata(d);
+	struct decoder_data *data = get_decoder_data(ir_dev);
+
+	if (!data)
+		return -EINVAL;
+
+	if (data->enabled)
+		return sprintf(buf, "1\n");
+	else
+	return sprintf(buf, "0\n");
+}
+
+static DEVICE_ATTR(enabled, S_IRUGO | S_IWUSR, show_enabled, store_enabled);
+
+static struct attribute *decoder_attributes[] = {
+	&dev_attr_enabled.attr,
+	NULL
+};
+
+static struct attribute_group decoder_attribute_group = {
+	.name	= "rc6_decoder",
+	.attrs	= decoder_attributes,
+};
+
+static enum rc6_mode rc6_mode(struct decoder_data *data) {
+	switch (data->header & RC6_MODE_MASK) {
+	case 0:
+		return RC6_MODE_0;
+	case 6:
+		if (!data->toggle)
+			return RC6_MODE_6A;
+		/* fall through */
+	default:
+		return RC6_MODE_UNKNOWN;
+	}
+}
+
+/**
+ * ir_rc6_decode() - Decode one RC6 pulse or space
+ * @input_dev:	the struct input_dev descriptor of the device
+ * @duration:	duration of pulse/space in ns
+ *
+ * This function returns -EINVAL if the pulse violates the state machine
+ */
+static int ir_rc6_decode(struct input_dev *input_dev, s64 duration)
+{
+	struct decoder_data *data;
+	struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
+	u32 scancode;
+	u8 toggle;
+	int u;
+
+	data = get_decoder_data(ir_dev);
+	if (!data)
+		return -EINVAL;
+
+	if (!data->enabled)
+		return 0;
+
+	if (IS_RESET(duration)) {
+		data->state = STATE_INACTIVE;
+		return 0;
+	}
+

drivers/media/IR/ir-rc6-decoder.c new file +60 -0

+	switch (data->state) {
+
+	case STATE_INACTIVE:
+		if (u >= RC6_PREFIX_PULSE - 1 && u <= RC6_PREFIX_PULSE + 1) {
+			data->state = STATE_PREFIX_SPACE;
+			data->count = 0;
+			return 0;
+		}
+		break;
+
+	case STATE_PREFIX_SPACE:
+		if (u == RC6_PREFIX_SPACE) {
+			data->state = STATE_HEADER_BIT_START;
+			return 0;
+		}
+		break;
+
+	case STATE_HEADER_BIT_START:
+		if (DURATION(u) == 1) {
+			data->header <<= 1;
+			if (IS_PULSE(u))
+				data->header |= 1;
+			data->count++;
+			data->last_unit = u;
+			data->state = STATE_HEADER_BIT_END;
+			return 0;
+		}
+		break;
+
+	case STATE_HEADER_BIT_END:
+		if (IS_TRANSITION(u, data->last_unit)) {
+			if (data->count == RC6_HEADER_NBITS)
+				data->state = STATE_TOGGLE_START;
+			else
+				data->state = STATE_HEADER_BIT_START;
+
+			DECREASE_DURATION(u, 1);
+			goto again;
+		}
+		break;
+
+	case STATE_TOGGLE_START:
+		if (DURATION(u) == 2) {
+			data->toggle = IS_PULSE(u);
+			data->last_unit = u;
+			data->state = STATE_TOGGLE_END;
+			return 0;
+		}
+		break;
+
+	case STATE_TOGGLE_END:
+		if (IS_TRANSITION(u, data->last_unit) && DURATION(u) >= 2) {
+			data->state = STATE_BODY_BIT_START;
+			data->last_unit = u;
+			DECREASE_DURATION(u, 2);
+			data->count = 0;
+
+			if (!(data->header & RC6_STARTBIT_MASK)) {
+				IR_dprintk(1, "RC6 invalid start bit\n");
+				break;

drivers/media/IR/ir-rc6-decoder.c new file +49 -0

+				if ((DURATION(u) == 0 && IS_SPACE(data->last_unit)) || DURATION(u) > 0)
+					data->wanted_bits = RC6_6A_LARGE_NBITS;
+				else
+					data->wanted_bits = RC6_6A_SMALL_NBITS;
+				break;
+			default:
+				IR_dprintk(1, "RC6 unknown mode\n");
+				goto out;
+			}
+			goto again;
+		}
+		break;
+
+	case STATE_BODY_BIT_START:
+		if (DURATION(u) == 1) {
+			data->body <<= 1;
+			if (IS_PULSE(u))
+				data->body |= 1;
+			data->count++;
+			data->last_unit = u;
+
+			/*
+			 * If the last bit is one, a space will merge
+			 * with the silence after the command.
+			 */
+			if (IS_PULSE(u) && data->count == data->wanted_bits) {
+				data->state = STATE_FINISHED;
+				goto again;
+			}
+
+			data->state = STATE_BODY_BIT_END;
+			return 0;
+		}
+		break;
+
+	case STATE_BODY_BIT_END:
+		if (IS_TRANSITION(u, data->last_unit)) {
+			if (data->count == data->wanted_bits)
+				data->state = STATE_FINISHED;
+			else
+				data->state = STATE_BODY_BIT_START;
+
+			DECREASE_DURATION(u, 1);
+			goto again;
+		}
+		break;
+
+	case STATE_FINISHED:
+		switch (rc6_mode(data)) {

drivers/media/IR/ir-rc6-decoder.c new file +94 -0

+			} else {
+				toggle = 0;
+				scancode = data->body & 0xffffff;
+			}
+
+			IR_dprintk(1, "RC6(6A) scancode 0x%08x (toggle: %u)\n",
+				   scancode, toggle);
+			break;
+		default:
+			IR_dprintk(1, "RC6 unknown mode\n");
+			goto out;
+		}
+
+		ir_keydown(input_dev, scancode, toggle);
+		data->state = STATE_INACTIVE;
+		return 0;
+	}
+
+out:
+	IR_dprintk(1, "RC6 decode failed at state %i (%i units, %ius)\n",
+		   data->state, u, TO_US(duration));
+	data->state = STATE_INACTIVE;
+	return -EINVAL;
+}
+
+static int ir_rc6_register(struct input_dev *input_dev)
+{
+	struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
+	struct decoder_data *data;
+	int rc;
+
+	rc = sysfs_create_group(&ir_dev->dev.kobj, &decoder_attribute_group);
+	if (rc < 0)
+		return rc;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data) {
+		sysfs_remove_group(&ir_dev->dev.kobj, &decoder_attribute_group);
+		return -ENOMEM;
+	}
+
+	data->ir_dev = ir_dev;
+	data->enabled = 1;
+
+	spin_lock(&decoder_lock);
+	list_add_tail(&data->list, &decoder_list);
+	spin_unlock(&decoder_lock);
+
+	return 0;
+}
+
+static int ir_rc6_unregister(struct input_dev *input_dev)
+{
+	struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
+	static struct decoder_data *data;
+
+	data = get_decoder_data(ir_dev);
+	if (!data)
+		return 0;
+
+	sysfs_remove_group(&ir_dev->dev.kobj, &decoder_attribute_group);
+
+	spin_lock(&decoder_lock);
+	list_del(&data->list);
+	spin_unlock(&decoder_lock);
+
+	return 0;
+}
+
+static struct ir_raw_handler rc6_handler = {
+	.decode		= ir_rc6_decode,
+	.raw_register	= ir_rc6_register,
+	.raw_unregister	= ir_rc6_unregister,
+};
+
+static int __init ir_rc6_decode_init(void)
+{
+	ir_raw_handler_register(&rc6_handler);
+
+	printk(KERN_INFO "IR RC6 protocol handler initialized\n");
+	return 0;
+}
+
+static void __exit ir_rc6_decode_exit(void)
+{
+	ir_raw_handler_unregister(&rc6_handler);
+}
+
+module_init(ir_rc6_decode_init);
+module_exit(ir_rc6_decode_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("David Härdeman <[email protected]>");
+MODULE_DESCRIPTION("RC6 IR protocol decoder");

drivers/media/IR/ir-sysfs.c +2 -0

index a222d4f..d7ec973 100644
@@ -60,6 +60,8 @@ static ssize_t show_protocol(struct device *d,
 		s = "pulse-distance";
 	else if (ir_type == IR_TYPE_NEC)
 		s = "nec";
+	else if (ir_type == IR_TYPE_RC6)
+		s = "rc6";
 	else
 		s = "other";
 

include/media/rc-map.h +1 -1

index 3b7fe5a..11f6618 100644
@@ -15,6 +15,7 @@
 #define IR_TYPE_RC5	(1  << 0)	/* Philips RC5 protocol */
 #define IR_TYPE_PD	(1  << 1)	/* Pulse distance encoded IR */
 #define IR_TYPE_NEC	(1  << 2)
+#define IR_TYPE_RC6	(1  << 3)	/* Philips RC6 protocol */
 #define IR_TYPE_OTHER	(1u << 31)
 
 struct ir_scancode {
 
--

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Quoted 19 lines · David Härdeman

drivers/media/IR/ir-rc6-decoder.c new file +12 -0

new file mode 100644
index 0000000..ccc5be2
@@ -0,0 +1,412 @@
+/* ir-rc6-decoder.c - A decoder for the RC6 IR protocol
+ *
+ * Copyright (C) 2010 by David Härdeman <[email protected]>
+ *
+ * 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.

drivers/media/IR/ir-rc6-decoder.c line 22

Quoted 10 lines

drivers/media/IR/ir-rc6-decoder.c new file +10 -0

+ */
+
+#include "ir-core-priv.h"
+
+/*
+ * This decoder currently supports:
+ * RC6-0-16	(standard toggle bit in header)
+ * RC6-6A-24	(no toggle bit)
+ * RC6-6A-32	(MCE version with toggle bit in body)
+ */

Just for reference for review:

http://slycontrol.ru/scr/kb/rc6.htm
http://www.picbasic.nl/info_rc6_uk.htm

RC6 Mode 0:

prefix mark:  111111
prefix space: 00
start bit:    10           (biphase encoding of '1')
mode bits:    010101       (biphase encoding of '000')
toggle bits:  0011 or 1100 (double duration biphase coding of '0' or '1')
system byte:  xxxxxxxxxxxxxxxx (biphase encoding of 8 bits)
command byte: yyyyyyyyyyyyyyyy (biphase encoding of 8 bits)

RC6 Mode 6A:

prefix mark:   111111
prefix space:  00
start bit:     10           (biphase encoding of '1')
mode bits:     101001       (biphase encoding of '110' for '6') 
trailer bits:  0011         (double duration biphase encoding of '0' for 'A')
customer len:  01 or 10     (biphase encoding of '0' for 7 bits or '1' for 15 bits)
customer bits: xxxxxxxxxxxxxx (biphase encoding of 7 bits for a short customer code)
		or
               xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx (biphase encoding of 15 bits for a long customer code)
system byte:   yyyyyyyyyyyyyyyy (biphase encoding of 8 bits)
command byte:  zzzzzzzzzzzzzzzz (biphase encoding of 8 bits)

drivers/media/IR/ir-rc6-decoder.c line 28

Quoted 5 lines

drivers/media/IR/ir-rc6-decoder.c new file +5 -0

+#define RC6_UNIT		444444	/* us */
+#define RC6_HEADER_NBITS	4	/* not including toggle bit */
+#define RC6_0_NBITS		16
+#define RC6_6A_SMALL_NBITS	24
+#define RC6_6A_LARGE_NBITS	32

According to the slycontrol.ru website, the data length is, in theory OEM dependent for Mode 6A, limited to a max of 24 bits (3 bytes) after a short customer code and 128 bits (16 bytes) after a long customer code.

I don't know what the reality is for existing remotes.

Would it be better to look for the signal free time of 6 RC6_UNITs to declare the end of reception, instead of a bit count?

drivers/media/IR/ir-rc6-decoder.c line 33

Quoted 5 lines

drivers/media/IR/ir-rc6-decoder.c new file +5 -0

+#define RC6_PREFIX_PULSE	PULSE(6)
+#define RC6_PREFIX_SPACE	SPACE(2)
+#define RC6_MODE_MASK		0x07	/* for the header bits */
+#define RC6_STARTBIT_MASK	0x08	/* for the header bits */
+#define RC6_6A_MCE_TOGGLE_MASK	0x8000	/* for the body bits */

That's an OEM specific toggle bit.

It is likely more properly named
RC6_6A_MS_TOGGLE_MASK. See slide 6 of:

http://download.microsoft.com/download/9/8/f/98f3fe47-dfc3-4e74-92a3-088782200fe7/TWEN05007_WinHEC05.ppt

(Although in reality, every remote that wants to work with stock MS drivers will use it.)

Quoted 145 lines

drivers/media/IR/ir-rc6-decoder.c new file +145 -0

+
+/* Used to register rc6_decoder clients */
+static LIST_HEAD(decoder_list);
+static DEFINE_SPINLOCK(decoder_lock);
+
+enum rc6_mode {
+	RC6_MODE_0,
+	RC6_MODE_6A,
+	RC6_MODE_UNKNOWN,
+};
+
+enum rc6_state {
+	STATE_INACTIVE,
+	STATE_PREFIX_SPACE,
+	STATE_HEADER_BIT_START,
+	STATE_HEADER_BIT_END,
+	STATE_TOGGLE_START,
+	STATE_TOGGLE_END,
+	STATE_BODY_BIT_START,
+	STATE_BODY_BIT_END,
+	STATE_FINISHED,
+};
+
+struct decoder_data {
+	struct list_head	list;
+	struct ir_input_dev	*ir_dev;
+	int			enabled:1;
+
+	/* State machine control */
+	enum rc6_state		state;
+	u8			header;
+	u32			body;
+	int			last_unit;
+	bool			toggle;
+	unsigned		count;
+	unsigned		wanted_bits;
+};
+
+
+/**
+ * get_decoder_data()	- gets decoder data
+ * @input_dev:	input device
+ *
+ * Returns the struct decoder_data that corresponds to a device
+ */
+static struct decoder_data *get_decoder_data(struct  ir_input_dev *ir_dev)
+{
+	struct decoder_data *data = NULL;
+
+	spin_lock(&decoder_lock);
+	list_for_each_entry(data, &decoder_list, list) {
+		if (data->ir_dev == ir_dev)
+			break;
+	}
+	spin_unlock(&decoder_lock);
+	return data;
+}
+
+static ssize_t store_enabled(struct device *d,
+			     struct device_attribute *mattr,
+			     const char *buf,
+			     size_t len)
+{
+	unsigned long value;
+	struct ir_input_dev *ir_dev = dev_get_drvdata(d);
+	struct decoder_data *data = get_decoder_data(ir_dev);
+
+	if (!data)
+		return -EINVAL;
+
+	if (strict_strtoul(buf, 10, &value) || value > 1)
+		return -EINVAL;
+
+	data->enabled = value;
+
+	return len;
+}
+
+static ssize_t show_enabled(struct device *d,
+			     struct device_attribute *mattr, char *buf)
+{
+	struct ir_input_dev *ir_dev = dev_get_drvdata(d);
+	struct decoder_data *data = get_decoder_data(ir_dev);
+
+	if (!data)
+		return -EINVAL;
+
+	if (data->enabled)
+		return sprintf(buf, "1\n");
+	else
+	return sprintf(buf, "0\n");
+}
+
+static DEVICE_ATTR(enabled, S_IRUGO | S_IWUSR, show_enabled, store_enabled);
+
+static struct attribute *decoder_attributes[] = {
+	&dev_attr_enabled.attr,
+	NULL
+};
+
+static struct attribute_group decoder_attribute_group = {
+	.name	= "rc6_decoder",
+	.attrs	= decoder_attributes,
+};
+
+static enum rc6_mode rc6_mode(struct decoder_data *data) {
+	switch (data->header & RC6_MODE_MASK) {
+	case 0:
+		return RC6_MODE_0;
+	case 6:
+		if (!data->toggle)
+			return RC6_MODE_6A;
+		/* fall through */
+	default:
+		return RC6_MODE_UNKNOWN;
+	}
+}
+
+/**
+ * ir_rc6_decode() - Decode one RC6 pulse or space
+ * @input_dev:	the struct input_dev descriptor of the device
+ * @duration:	duration of pulse/space in ns
+ *
+ * This function returns -EINVAL if the pulse violates the state machine
+ */
+static int ir_rc6_decode(struct input_dev *input_dev, s64 duration)
+{
+	struct decoder_data *data;
+	struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
+	u32 scancode;
+	u8 toggle;
+	int u;
+
+	data = get_decoder_data(ir_dev);
+	if (!data)
+		return -EINVAL;
+
+	if (!data->enabled)
+		return 0;
+
+	if (IS_RESET(duration)) {
+		data->state = STATE_INACTIVE;
+		return 0;
+	}
+

drivers/media/IR/ir-rc6-decoder.c line 188

Quoted 10 lines

drivers/media/IR/ir-rc6-decoder.c new file +10 -0

+	u =  TO_UNITS(duration, RC6_UNIT);
+	if (DURATION(u) == 0)
+		goto out;
+
+again:
+	IR_dprintk(2, "RC6 decode started at state %i (%i units, %ius)\n",
+		   data->state, u, TO_US(duration));
+
+	if (DURATION(u) == 0 && data->state != STATE_FINISHED)
+		return 0;

Isn't there a better way to structure the logic to break up two adjacent pulse units than with goto's out of the switch back up to here?

A do {} while() loop would have been much clearer.

Quoted 65 lines

drivers/media/IR/ir-rc6-decoder.c new file +65 -0

+	switch (data->state) {
+
+	case STATE_INACTIVE:
+		if (u >= RC6_PREFIX_PULSE - 1 && u <= RC6_PREFIX_PULSE + 1) {
+			data->state = STATE_PREFIX_SPACE;
+			data->count = 0;
+			return 0;
+		}
+		break;
+
+	case STATE_PREFIX_SPACE:
+		if (u == RC6_PREFIX_SPACE) {
+			data->state = STATE_HEADER_BIT_START;
+			return 0;
+		}
+		break;
+
+	case STATE_HEADER_BIT_START:
+		if (DURATION(u) == 1) {
+			data->header <<= 1;
+			if (IS_PULSE(u))
+				data->header |= 1;
+			data->count++;
+			data->last_unit = u;
+			data->state = STATE_HEADER_BIT_END;
+			return 0;
+		}
+		break;
+
+	case STATE_HEADER_BIT_END:
+		if (IS_TRANSITION(u, data->last_unit)) {
+			if (data->count == RC6_HEADER_NBITS)
+				data->state = STATE_TOGGLE_START;
+			else
+				data->state = STATE_HEADER_BIT_START;
+
+			DECREASE_DURATION(u, 1);
+			goto again;
+		}
+		break;
+
+	case STATE_TOGGLE_START:
+		if (DURATION(u) == 2) {
+			data->toggle = IS_PULSE(u);
+			data->last_unit = u;
+			data->state = STATE_TOGGLE_END;
+			return 0;
+		}
+		break;
+
+	case STATE_TOGGLE_END:
+		if (IS_TRANSITION(u, data->last_unit) && DURATION(u) >= 2) {
+			data->state = STATE_BODY_BIT_START;
+			data->last_unit = u;
+			DECREASE_DURATION(u, 2);
+			data->count = 0;
+
+			if (!(data->header & RC6_STARTBIT_MASK)) {
+				IR_dprintk(1, "RC6 invalid start bit\n");
+				break;
+			}
+
+			switch (rc6_mode(data)) {
+			case RC6_MODE_0:
+				data->wanted_bits = RC6_0_NBITS;

drivers/media/IR/ir-rc6-decoder.c line 259

Quoted 5 lines

drivers/media/IR/ir-rc6-decoder.c new file +5 -0

+				break;
+			case RC6_MODE_6A:
+				/* This might look weird, but we basically
+				   check the value of the first body bit to
+				   determine the number of bits in mode 6A */

This bit basically only tells you the length of the customer code: 7 or 15 bits.

Quoted 53 lines

drivers/media/IR/ir-rc6-decoder.c new file +53 -0

+				if ((DURATION(u) == 0 && IS_SPACE(data->last_unit)) || DURATION(u) > 0)
+					data->wanted_bits = RC6_6A_LARGE_NBITS;
+				else
+					data->wanted_bits = RC6_6A_SMALL_NBITS;
+				break;
+			default:
+				IR_dprintk(1, "RC6 unknown mode\n");
+				goto out;
+			}
+			goto again;
+		}
+		break;
+
+	case STATE_BODY_BIT_START:
+		if (DURATION(u) == 1) {
+			data->body <<= 1;
+			if (IS_PULSE(u))
+				data->body |= 1;
+			data->count++;
+			data->last_unit = u;
+
+			/*
+			 * If the last bit is one, a space will merge
+			 * with the silence after the command.
+			 */
+			if (IS_PULSE(u) && data->count == data->wanted_bits) {
+				data->state = STATE_FINISHED;
+				goto again;
+			}
+
+			data->state = STATE_BODY_BIT_END;
+			return 0;
+		}
+		break;
+
+	case STATE_BODY_BIT_END:
+		if (IS_TRANSITION(u, data->last_unit)) {
+			if (data->count == data->wanted_bits)
+				data->state = STATE_FINISHED;
+			else
+				data->state = STATE_BODY_BIT_START;
+
+			DECREASE_DURATION(u, 1);
+			goto again;
+		}
+		break;
+
+	case STATE_FINISHED:
+		switch (rc6_mode(data)) {
+		case RC6_MODE_0:
+			scancode = data->body & 0xffff;
+			toggle = data->toggle;
+			IR_dprintk(1, "RC6(0) scancode 0x%04x (toggle: %u)\n",

drivers/media/IR/ir-rc6-decoder.c line 318

Quoted 6 lines

drivers/media/IR/ir-rc6-decoder.c new file +6 -0

+				   scancode, toggle);
+			break;
+		case RC6_MODE_6A:
+			if (data->wanted_bits == RC6_6A_LARGE_NBITS) {
+				toggle = data->body & RC6_6A_MCE_TOGGLE_MASK ? 1 : 0;
+				scancode = data->body & ~RC6_6A_MCE_TOGGLE_MASK;

Technically this depends on the OEM.

In reality, every RC6 Mode 6A
remote that wants to work with Microsoft stock drivers will likely use this bit as a toggle.

Quoted 72 lines · Andy Walls

Quoted 19 lines · David Härdeman

drivers/media/IR/ir-rc6-decoder.c new file +12 -0

new file mode 100644
index 0000000..ccc5be2
@@ -0,0 +1,412 @@
+/* ir-rc6-decoder.c - A decoder for the RC6 IR protocol
+ *
+ * Copyright (C) 2010 by David Härdeman <[email protected]>
+ *
+ * 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.

drivers/media/IR/ir-rc6-decoder.c line 22

Quoted 10 lines

drivers/media/IR/ir-rc6-decoder.c new file +10 -0

+ */
+
+#include "ir-core-priv.h"
+
+/*
+ * This decoder currently supports:
+ * RC6-0-16	(standard toggle bit in header)
+ * RC6-6A-24	(no toggle bit)
+ * RC6-6A-32	(MCE version with toggle bit in body)
+ */

Just for reference for review:

http://slycontrol.ru/scr/kb/rc6.htm
http://www.picbasic.nl/info_rc6_uk.htm

RC6 Mode 0:

prefix mark:  111111
prefix space: 00
start bit:    10           (biphase encoding of '1')
mode bits:    010101       (biphase encoding of '000')
toggle bits:  0011 or 1100 (double duration biphase coding of '0' or '1')
system byte:  xxxxxxxxxxxxxxxx (biphase encoding of 8 bits)
command byte: yyyyyyyyyyyyyyyy (biphase encoding of 8 bits)

RC6 Mode 6A:

prefix mark:   111111
prefix space:  00
start bit:     10           (biphase encoding of '1')
mode bits:     101001       (biphase encoding of '110' for '6') 
trailer bits:  0011         (double duration biphase encoding of '0' for 'A')
customer len:  01 or 10     (biphase encoding of '0' for 7 bits or '1' for 15 bits)
customer bits: xxxxxxxxxxxxxx (biphase encoding of 7 bits for a short customer code)
		or
               xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx (biphase encoding of 15 bits for a long customer code)
system byte:   yyyyyyyyyyyyyyyy (biphase encoding of 8 bits)
command byte:  zzzzzzzzzzzzzzzz (biphase encoding of 8 bits)

drivers/media/IR/ir-rc6-decoder.c line 28

Quoted 5 lines

drivers/media/IR/ir-rc6-decoder.c new file +5 -0

+#define RC6_UNIT		444444	/* us */
+#define RC6_HEADER_NBITS	4	/* not including toggle bit */
+#define RC6_0_NBITS		16
+#define RC6_6A_SMALL_NBITS	24
+#define RC6_6A_LARGE_NBITS	32

According to the slycontrol.ru website, the data length is, in theory OEM dependent for Mode 6A, limited to a max of 24 bits (3 bytes) after a short customer code and 128 bits (16 bytes) after a long customer code.

Quoted 4 lines

I don't know what the reality is for existing remotes.

Would it be better to look for the signal free time of 6 RC6_UNITs to declare the end of reception, instead of a bit count?

Yes, it might be better from a correctness point of view, and I think it might be a worthwhile change if we want to support a few more odd remotes (although the only one I'm aware of - even after trawling through lots of lirc configs, decodeir.dll configs and remotecentral configs - is the "Sky" remote which seems to use a short customer code and a 12 bit body).

The thing is though, that with the different 32 bit scancodes, we can't anyway represent anything beyond a 32 bit message body (including the customer code, which should be included in the scancode).

I have a
proposal on changing the scancodes used in ir-code, but I haven't written up the details yet.

It's also interesting to note that the ProntoEdit NG program, which is written by Philips, only allows a 24/32 bit body (including the customer bits).

Quoted 7 lines

drivers/media/IR/ir-rc6-decoder.c line 33

Quoted 5 lines

drivers/media/IR/ir-rc6-decoder.c new file +5 -0

+#define RC6_PREFIX_PULSE	PULSE(6)
+#define RC6_PREFIX_SPACE	SPACE(2)
+#define RC6_MODE_MASK		0x07	/* for the header bits */
+#define RC6_STARTBIT_MASK	0x08	/* for the header bits */
+#define RC6_6A_MCE_TOGGLE_MASK	0x8000	/* for the body bits */

That's an OEM specific toggle bit.

Umm, yes I know? That's why the define includes the "_MCE_" part and also what the comment in the beginning of the decoder says:

* RC6-6A-32 (MCE version with toggle bit in body)

Quoted 3 lines

It is likely more properly named
RC6_6A_MS_TOGGLE_MASK. See slide 6 of:

Quoted 4 lines

http://download.microsoft.com/download/9/8/f/98f3fe47-dfc3-4e74-92a3-088782200fe7/TWEN05007_WinHEC05.ppt

(Although in reality, every remote that wants to work with stock MS drivers will use it.)

I'm not sure what your point is...it's already called RC6_6A_MCE_TOGGLE_MASK, as in "RC6 6A Windows Media Center Edition Toggle Mask".

Quoted 15 lines

drivers/media/IR/ir-rc6-decoder.c line 188

Quoted 6 lines

drivers/media/IR/ir-rc6-decoder.c new file +6 -0

+again:
+	IR_dprintk(2, "RC6 decode started at state %i (%i units, %ius)\n",
+		   data->state, u, TO_US(duration));
+
+	if (DURATION(u) == 0 && data->state != STATE_FINISHED)
+		return 0;

Isn't there a better way to structure the logic to break up two adjacent pulse units than with goto's out of the switch back up to here?

A do {} while() loop would have been much clearer.

Quoted 6 lines

drivers/media/IR/ir-rc6-decoder.c line 318

Quoted 4 lines

drivers/media/IR/ir-rc6-decoder.c new file +4 -0

+		case RC6_MODE_6A:
+			if (data->wanted_bits == RC6_6A_LARGE_NBITS) {
+				toggle = data->body & RC6_6A_MCE_TOGGLE_MASK ? 1 : 0;
+				scancode = data->body & ~RC6_6A_MCE_TOGGLE_MASK;

Technically this depends on the OEM.

I know, again it's mentioned in one of the first comments of the code.

Quoted 3 lines

In reality, every RC6 Mode 6A
remote that wants to work with Microsoft stock drivers will likely use this bit as a toggle.

We might want to check if the (long) customer code matches 0x800F (if I remember correctly) and apply the MCE behaviour only then, but it might also come back to bite us in the ass if, for example, different customers have implemented the same definition of the body.

Then again, as far as I can remeber, the Philips Pronto raw code for MCE commands doesn't include the customer code, which would indicate that it's fixed.

Another question is: if the customer code doesn't match, what do we do? The body could be defined as any random gibberish by vendor XYZ, including toggles and checksums which means that the scancode would change for each keypress if we blindly report the entire body as a 32 bit scancode.

drivers/media/IR/ir-rc6-decoder.c line 188

Quoted 6 lines · David Härdeman

drivers/media/IR/ir-rc6-decoder.c new file +6 -0

+again:
+	IR_dprintk(2, "RC6 decode started at state %i (%i units, %ius)\n",
+		   data->state, u, TO_US(duration));
+
+	if (DURATION(u) == 0 && data->state != STATE_FINISHED)
+		return 0;

Isn't there a better way to structure the logic to break up two adjacent pulse units than with goto's out of the switch back up to here?

A do {} while() loop would have been much clearer.