--- /dev/null
+/* ir-rc6-decoder.c - A decoder for the RC6 IR protocol
+ *
+ * Copyright (C) 2010 by David Härdeman <david@hardeman.nu>
+ *
+ * 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 "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)
+ */
+
+#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
+#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 */
+
+/* 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;
+ }
+
+ 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;
+
+ 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;
+ 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 */
+ 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",
+ 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;
+ } 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 <david@hardeman.nu>");
+MODULE_DESCRIPTION("RC6 IR protocol decoder");
projects / GitHub / MotorolaMobilityLLC / kernel-slsi.git / commitdiff