drivers/media/IR/ir-nec-decoder.c - kernel/skids - Git at Google

 /* ir-nec-decoder.c - handle NEC IR Pulse/Space protocol
  *
  * Copyright (C) 2010 by Mauro Carvalho Chehab <mchehab@redhat.com>
  *
  * 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.
  */

 #include <linux/bitrev.h>
 #include "ir-core-priv.h"

 #define NEC_NBITS		32
 #define NEC_UNIT		562500  /* ns */
 #define NEC_HEADER_PULSE	(16 * NEC_UNIT)
 #define NECX_HEADER_PULSE	(8  * NEC_UNIT) /* Less common NEC variant */
 #define NEC_HEADER_SPACE	(8  * NEC_UNIT)
 #define NEC_REPEAT_SPACE	(8  * NEC_UNIT)
 #define NEC_BIT_PULSE		(1  * NEC_UNIT)
 #define NEC_BIT_0_SPACE		(1  * NEC_UNIT)
 #define NEC_BIT_1_SPACE		(3  * NEC_UNIT)
 #define	NEC_TRAILER_PULSE	(1  * NEC_UNIT)
 #define	NEC_TRAILER_SPACE	(10 * NEC_UNIT) /* even longer in reality */

 /* Used to register nec_decoder clients */
 static LIST_HEAD(decoder_list);
 static DEFINE_SPINLOCK(decoder_lock);

 enum nec_state {
 	STATE_INACTIVE,
 	STATE_HEADER_SPACE,
 	STATE_BIT_PULSE,
 	STATE_BIT_SPACE,
 	STATE_TRAILER_PULSE,
 	STATE_TRAILER_SPACE,
 };

 struct decoder_data {
 	struct list_head	list;
 	struct ir_input_dev	*ir_dev;
 	int			enabled:1;

 	/* State machine control */
 	enum nec_state		state;
 	u32			nec_bits;
 	unsigned		count;
 };


 /**
  * 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	= "nec_decoder",
 	.attrs	= decoder_attributes,
 };

 /**
  * ir_nec_decode() - Decode one NEC pulse or space
  * @input_dev:	the struct input_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_nec_decode(struct input_dev *input_dev, struct ir_raw_event ev)
 {
 	struct decoder_data *data;
 	struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
 	u32 scancode;
 	u8 address, not_address, command, not_command;

 	data = get_decoder_data(ir_dev);
 	if (!data)
 		return -EINVAL;

 	if (!data->enabled)
 		return 0;

 	if (IS_RESET(ev)) {
 		data->state = STATE_INACTIVE;
 		return 0;
 	}

 	IR_dprintk(2, "NEC decode started at state %d (%uus %s)\n",
 		   data->state, TO_US(ev.duration), TO_STR(ev.pulse));

 	switch (data->state) {

 	case STATE_INACTIVE:
 		if (!ev.pulse)
 			break;

 		if (!eq_margin(ev.duration, NEC_HEADER_PULSE, NEC_UNIT / 2) &&
 		    !eq_margin(ev.duration, NECX_HEADER_PULSE, NEC_UNIT / 2))
 			break;

 		data->count = 0;
 		data->state = STATE_HEADER_SPACE;
 		return 0;

 	case STATE_HEADER_SPACE:
 		if (ev.pulse)
 			break;

 		if (eq_margin(ev.duration, NEC_HEADER_SPACE, NEC_UNIT / 2)) {
 			data->state = STATE_BIT_PULSE;
 			return 0;
 		} else if (eq_margin(ev.duration, NEC_REPEAT_SPACE, NEC_UNIT / 2)) {
 			ir_repeat(input_dev);
 			IR_dprintk(1, "Repeat last key\n");
 			data->state = STATE_TRAILER_PULSE;
 			return 0;
 		}

 		break;

 	case STATE_BIT_PULSE:
 		if (!ev.pulse)
 			break;

 		if (!eq_margin(ev.duration, NEC_BIT_PULSE, NEC_UNIT / 2))
 			break;

 		data->state = STATE_BIT_SPACE;
 		return 0;

 	case STATE_BIT_SPACE:
 		if (ev.pulse)
 			break;

 		data->nec_bits <<= 1;
 		if (eq_margin(ev.duration, NEC_BIT_1_SPACE, NEC_UNIT / 2))
 			data->nec_bits |= 1;
 		else if (!eq_margin(ev.duration, NEC_BIT_0_SPACE, NEC_UNIT / 2))
 			break;
 		data->count++;

 		if (data->count == NEC_NBITS)
 			data->state = STATE_TRAILER_PULSE;
 		else
 			data->state = STATE_BIT_PULSE;

 		return 0;

 	case STATE_TRAILER_PULSE:
 		if (!ev.pulse)
 			break;

 		if (!eq_margin(ev.duration, NEC_TRAILER_PULSE, NEC_UNIT / 2))
 			break;

 		data->state = STATE_TRAILER_SPACE;
 		return 0;

 	case STATE_TRAILER_SPACE:
 		if (ev.pulse)
 			break;

 		if (!geq_margin(ev.duration, NEC_TRAILER_SPACE, NEC_UNIT / 2))
 			break;

 		address     = bitrev8((data->nec_bits >> 24) & 0xff);
 		not_address = bitrev8((data->nec_bits >> 16) & 0xff);
 		command	    = bitrev8((data->nec_bits >>  8) & 0xff);
 		not_command = bitrev8((data->nec_bits >>  0) & 0xff);

 		if ((command ^ not_command) != 0xff) {
 			IR_dprintk(1, "NEC checksum error: received 0x%08x\n",
 				   data->nec_bits);
 			break;
 		}

 		if ((address ^ not_address) != 0xff) {
 			/* Extended NEC */
 			scancode = address     << 16 |
 				   not_address <<  8 |
 				   command;
 			IR_dprintk(1, "NEC (Ext) scancode 0x%06x\n", scancode);
 		} else {
 			/* Normal NEC */
 			scancode = address << 8 | command;
 			IR_dprintk(1, "NEC scancode 0x%04x\n", scancode);
 		}

 		ir_keydown(input_dev, scancode, 0);
 		data->state = STATE_INACTIVE;
 		return 0;
 	}

 	IR_dprintk(1, "NEC decode failed at state %d (%uus %s)\n",
 		   data->state, TO_US(ev.duration), TO_STR(ev.pulse));
 	data->state = STATE_INACTIVE;
 	return -EINVAL;
 }

 static int ir_nec_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_nec_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 nec_handler = {
 	.decode		= ir_nec_decode,
 	.raw_register	= ir_nec_register,
 	.raw_unregister	= ir_nec_unregister,
 };

 static int __init ir_nec_decode_init(void)
 {
 	ir_raw_handler_register(&nec_handler);

 	printk(KERN_INFO "IR NEC protocol handler initialized\n");
 	return 0;
 }

 static void __exit ir_nec_decode_exit(void)
 {
 	ir_raw_handler_unregister(&nec_handler);
 }

 module_init(ir_nec_decode_init);
 module_exit(ir_nec_decode_exit);

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>");
 MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
 MODULE_DESCRIPTION("NEC IR protocol decoder");
	/* ir-nec-decoder.c - handle NEC IR Pulse/Space protocol
	*
	* Copyright (C) 2010 by Mauro Carvalho Chehab <mchehab@redhat.com>
	*
	* 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.
	*/

	#include <linux/bitrev.h>
	#include "ir-core-priv.h"

	#define NEC_NBITS 32
	#define NEC_UNIT 562500 /* ns */
	#define NEC_HEADER_PULSE (16 * NEC_UNIT)
	#define NECX_HEADER_PULSE (8 * NEC_UNIT) /* Less common NEC variant */
	#define NEC_HEADER_SPACE (8 * NEC_UNIT)
	#define NEC_REPEAT_SPACE (8 * NEC_UNIT)
	#define NEC_BIT_PULSE (1 * NEC_UNIT)
	#define NEC_BIT_0_SPACE (1 * NEC_UNIT)
	#define NEC_BIT_1_SPACE (3 * NEC_UNIT)
	#define NEC_TRAILER_PULSE (1 * NEC_UNIT)
	#define NEC_TRAILER_SPACE (10 * NEC_UNIT) /* even longer in reality */

	/* Used to register nec_decoder clients */
	static LIST_HEAD(decoder_list);
	static DEFINE_SPINLOCK(decoder_lock);

	enum nec_state {
	STATE_INACTIVE,
	STATE_HEADER_SPACE,
	STATE_BIT_PULSE,
	STATE_BIT_SPACE,
	STATE_TRAILER_PULSE,
	STATE_TRAILER_SPACE,
	};

	struct decoder_data {
	struct list_head list;
	struct ir_input_dev *ir_dev;
	int enabled:1;

	/* State machine control */
	enum nec_state state;
	u32 nec_bits;
	unsigned count;
	};


	/**
	* 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 = "nec_decoder",
	.attrs = decoder_attributes,
	};

	/**
	* ir_nec_decode() - Decode one NEC pulse or space
	* @input_dev: the struct input_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_nec_decode(struct input_dev *input_dev, struct ir_raw_event ev)
	{
	struct decoder_data *data;
	struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
	u32 scancode;
	u8 address, not_address, command, not_command;

	data = get_decoder_data(ir_dev);
	if (!data)
	return -EINVAL;

	if (!data->enabled)
	return 0;

	if (IS_RESET(ev)) {
	data->state = STATE_INACTIVE;
	return 0;
	}

	IR_dprintk(2, "NEC decode started at state %d (%uus %s)\n",
	data->state, TO_US(ev.duration), TO_STR(ev.pulse));

	switch (data->state) {

	case STATE_INACTIVE:
	if (!ev.pulse)
	break;

	if (!eq_margin(ev.duration, NEC_HEADER_PULSE, NEC_UNIT / 2) &&
	!eq_margin(ev.duration, NECX_HEADER_PULSE, NEC_UNIT / 2))
	break;

	data->count = 0;
	data->state = STATE_HEADER_SPACE;
	return 0;

	case STATE_HEADER_SPACE:
	if (ev.pulse)
	break;

	if (eq_margin(ev.duration, NEC_HEADER_SPACE, NEC_UNIT / 2)) {
	data->state = STATE_BIT_PULSE;
	return 0;
	} else if (eq_margin(ev.duration, NEC_REPEAT_SPACE, NEC_UNIT / 2)) {
	ir_repeat(input_dev);
	IR_dprintk(1, "Repeat last key\n");
	data->state = STATE_TRAILER_PULSE;
	return 0;
	}

	break;

	case STATE_BIT_PULSE:
	if (!ev.pulse)
	break;

	if (!eq_margin(ev.duration, NEC_BIT_PULSE, NEC_UNIT / 2))
	break;

	data->state = STATE_BIT_SPACE;
	return 0;

	case STATE_BIT_SPACE:
	if (ev.pulse)
	break;

	data->nec_bits <<= 1;
	if (eq_margin(ev.duration, NEC_BIT_1_SPACE, NEC_UNIT / 2))
	data->nec_bits \|= 1;
	else if (!eq_margin(ev.duration, NEC_BIT_0_SPACE, NEC_UNIT / 2))
	break;
	data->count++;

	if (data->count == NEC_NBITS)
	data->state = STATE_TRAILER_PULSE;
	else
	data->state = STATE_BIT_PULSE;

	return 0;

	case STATE_TRAILER_PULSE:
	if (!ev.pulse)
	break;

	if (!eq_margin(ev.duration, NEC_TRAILER_PULSE, NEC_UNIT / 2))
	break;

	data->state = STATE_TRAILER_SPACE;
	return 0;

	case STATE_TRAILER_SPACE:
	if (ev.pulse)
	break;

	if (!geq_margin(ev.duration, NEC_TRAILER_SPACE, NEC_UNIT / 2))
	break;

	address = bitrev8((data->nec_bits >> 24) & 0xff);
	not_address = bitrev8((data->nec_bits >> 16) & 0xff);
	command = bitrev8((data->nec_bits >> 8) & 0xff);
	not_command = bitrev8((data->nec_bits >> 0) & 0xff);

	if ((command ^ not_command) != 0xff) {
	IR_dprintk(1, "NEC checksum error: received 0x%08x\n",
	data->nec_bits);
	break;
	}

	if ((address ^ not_address) != 0xff) {
	/* Extended NEC */
	scancode = address << 16 \|
	not_address << 8 \|
	command;
	IR_dprintk(1, "NEC (Ext) scancode 0x%06x\n", scancode);
	} else {
	/* Normal NEC */
	scancode = address << 8 \| command;
	IR_dprintk(1, "NEC scancode 0x%04x\n", scancode);
	}

	ir_keydown(input_dev, scancode, 0);
	data->state = STATE_INACTIVE;
	return 0;
	}

	IR_dprintk(1, "NEC decode failed at state %d (%uus %s)\n",
	data->state, TO_US(ev.duration), TO_STR(ev.pulse));
	data->state = STATE_INACTIVE;
	return -EINVAL;
	}

	static int ir_nec_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_nec_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 nec_handler = {
	.decode = ir_nec_decode,
	.raw_register = ir_nec_register,
	.raw_unregister = ir_nec_unregister,
	};

	static int __init ir_nec_decode_init(void)
	{
	ir_raw_handler_register(&nec_handler);

	printk(KERN_INFO "IR NEC protocol handler initialized\n");
	return 0;
	}

	static void __exit ir_nec_decode_exit(void)
	{
	ir_raw_handler_unregister(&nec_handler);
	}

	module_init(ir_nec_decode_init);
	module_exit(ir_nec_decode_exit);

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>");
	MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
	MODULE_DESCRIPTION("NEC IR protocol decoder");