1 files changed, 324 insertions, 0 deletions
diff --git a/drivers/media/IR/ir-rc5-decoder.c b/drivers/media/IR/ir-rc5-decoder.c
new file mode 100644
index 000000000000..23cdb1b1a3bc
--- /dev/null
+++ b/drivers/media/IR/ir-rc5-decoder.c
@@ -0,0 +1,324 @@
+/* ir-rc5-decoder.c - handle RC5(x) 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.
+ */
+
+/*
+ * This code handles 14 bits RC5 protocols and 20 bits RC5x protocols.
+ * There are other variants that use a different number of bits.
+ * This is currently unsupported.
+ * It considers a carrier of 36 kHz, with a total of 14/20 bits, where
+ * the first two bits are start bits, and a third one is a filing bit
+ */
+
+#include "ir-core-priv.h"
+
+#define RC5_NBITS		14
+#define RC5X_NBITS		20
+#define CHECK_RC5X_NBITS	8
+#define RC5_UNIT		888888 /* ns */
+#define RC5_BIT_START		(1 * RC5_UNIT)
+#define RC5_BIT_END		(1 * RC5_UNIT)
+#define RC5X_SPACE		(4 * RC5_UNIT)
+
+/* Used to register rc5_decoder clients */
+static LIST_HEAD(decoder_list);
+static DEFINE_SPINLOCK(decoder_lock);
+
+enum rc5_state {
+	STATE_INACTIVE,
+	STATE_BIT_START,
+	STATE_BIT_END,
+	STATE_CHECK_RC5X,
+	STATE_FINISHED,
+};
+
+struct decoder_data {
+	struct list_head	list;
+	struct ir_input_dev	*ir_dev;
+	int			enabled:1;
+
+	/* State machine control */
+	enum rc5_state		state;
+	u32			rc5_bits;
+	struct ir_raw_event	prev_ev;
+	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	= "rc5_decoder",
+	.attrs	= decoder_attributes,
+};
+
+/**
+ * ir_rc5_decode() - Decode one RC-5 pulse or space
+ * @input_dev:	the struct input_dev descriptor of the device
+ * @ev:		the struct ir_raw_event descriptor of the pulse/space
+ *
+ * This function returns -EINVAL if the pulse violates the state machine
+ */
+static int ir_rc5_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);
+	u8 toggle;
+	u32 scancode;
+
+	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;
+	}
+
+	if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2))
+		goto out;
+
+again:
+	IR_dprintk(2, "RC5(x) decode started at state %i (%uus %s)\n",
+		   data->state, TO_US(ev.duration), TO_STR(ev.pulse));
+
+	if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2))
+		return 0;
+
+	switch (data->state) {
+
+	case STATE_INACTIVE:
+		if (!ev.pulse)
+			break;
+
+		data->state = STATE_BIT_START;
+		data->count = 1;
+		/* We just need enough bits to get to STATE_CHECK_RC5X */
+		data->wanted_bits = RC5X_NBITS;
+		decrease_duration(&ev, RC5_BIT_START);
+		goto again;
+
+	case STATE_BIT_START:
+		if (!eq_margin(ev.duration, RC5_BIT_START, RC5_UNIT / 2))
+			break;
+
+		data->rc5_bits <<= 1;
+		if (!ev.pulse)
+			data->rc5_bits |= 1;
+		data->count++;
+		data->prev_ev = ev;
+		data->state = STATE_BIT_END;
+		return 0;
+
+	case STATE_BIT_END:
+		if (!is_transition(&ev, &data->prev_ev))
+			break;
+
+		if (data->count == data->wanted_bits)
+			data->state = STATE_FINISHED;
+		else if (data->count == CHECK_RC5X_NBITS)
+			data->state = STATE_CHECK_RC5X;
+		else
+			data->state = STATE_BIT_START;
+
+		decrease_duration(&ev, RC5_BIT_END);
+		goto again;
+
+	case STATE_CHECK_RC5X:
+		if (!ev.pulse && geq_margin(ev.duration, RC5X_SPACE, RC5_UNIT / 2)) {
+			/* RC5X */
+			data->wanted_bits = RC5X_NBITS;
+			decrease_duration(&ev, RC5X_SPACE);
+		} else {
+			/* RC5 */
+			data->wanted_bits = RC5_NBITS;
+		}
+		data->state = STATE_BIT_START;
+		goto again;
+
+	case STATE_FINISHED:
+		if (ev.pulse)
+			break;
+
+		if (data->wanted_bits == RC5X_NBITS) {
+			/* RC5X */
+			u8 xdata, command, system;
+			xdata    = (data->rc5_bits & 0x0003F) >> 0;
+			command  = (data->rc5_bits & 0x00FC0) >> 6;
+			system   = (data->rc5_bits & 0x1F000) >> 12;
+			toggle   = (data->rc5_bits & 0x20000) ? 1 : 0;
+			command += (data->rc5_bits & 0x01000) ? 0 : 0x40;
+			scancode = system << 16 | command << 8 | xdata;
+
+			IR_dprintk(1, "RC5X scancode 0x%06x (toggle: %u)\n",
+				   scancode, toggle);
+
+		} else {
+			/* RC5 */
+			u8 command, system;
+			command  = (data->rc5_bits & 0x0003F) >> 0;
+			system   = (data->rc5_bits & 0x007C0) >> 6;
+			toggle   = (data->rc5_bits & 0x00800) ? 1 : 0;
+			command += (data->rc5_bits & 0x01000) ? 0 : 0x40;
+			scancode = system << 8 | command;
+
+			IR_dprintk(1, "RC5 scancode 0x%04x (toggle: %u)\n",
+				   scancode, toggle);
+		}
+
+		ir_keydown(input_dev, scancode, toggle);
+		data->state = STATE_INACTIVE;
+		return 0;
+	}
+
+out:
+	IR_dprintk(1, "RC5(x) decode failed at state %i (%uus %s)\n",
+		   data->state, TO_US(ev.duration), TO_STR(ev.pulse));
+	data->state = STATE_INACTIVE;
+	return -EINVAL;
+}
+
+static int ir_rc5_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_rc5_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 rc5_handler = {
+	.decode		= ir_rc5_decode,
+	.raw_register	= ir_rc5_register,
+	.raw_unregister	= ir_rc5_unregister,
+};
+
+static int __init ir_rc5_decode_init(void)
+{
+	ir_raw_handler_register(&rc5_handler);
+
+	printk(KERN_INFO "IR RC5(x) protocol handler initialized\n");
+	return 0;
+}
+
+static void __exit ir_rc5_decode_exit(void)
+{
+	ir_raw_handler_unregister(&rc5_handler);
+}
+
+module_init(ir_rc5_decode_init);
+module_exit(ir_rc5_decode_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>");
+MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
+MODULE_DESCRIPTION("RC5(x) IR protocol decoder");