1 files changed, 328 insertions, 0 deletions
diff --git a/drivers/media/IR/ir-nec-decoder.c b/drivers/media/IR/ir-nec-decoder.c
new file mode 100644
index 000000000000..ba79233112ef
--- /dev/null
+++ b/drivers/media/IR/ir-nec-decoder.c
@@ -0,0 +1,328 @@
+/* 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");