--- /dev/null
+/* ir-rc5-decoder.c - handle RC-5 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 only handles 14 bits RC-5 protocols. There are other variants
+ * that use a different number of bits. This is currently unsupported
+ */
+
+#include <media/ir-core.h>
+
+#define RC5_NBITS 14
+#define RC5_HALFBIT 888888 /* ns */
+#define RC5_BIT (RC5_HALFBIT * 2)
+#define RC5_DURATION (RC5_BIT * RC5_NBITS)
+
+#define is_rc5_halfbit(nsec) ((ev->delta.tv_nsec >= RC5_HALFBIT / 2) && \
+ (ev->delta.tv_nsec < RC5_HALFBIT + RC5_HALFBIT / 2))
+
+#define n_half(nsec) ((ev->delta.tv_nsec + RC5_HALFBIT / 2) / RC5_HALFBIT)
+
+/* Used to register rc5_decoder clients */
+static LIST_HEAD(decoder_list);
+static spinlock_t decoder_lock;
+
+enum rc5_state {
+ STATE_INACTIVE,
+ STATE_START2_SPACE,
+ STATE_START2_MARK,
+ STATE_MARKSPACE,
+ STATE_TRAILER_MARK,
+};
+
+static char *st_name[] = {
+ "Inactive",
+ "start2 sapce",
+ "start2 mark",
+ "mark",
+ "space",
+ "trailer"
+};
+
+struct rc5_code {
+ u8 address;
+ u8 command;
+};
+
+struct decoder_data {
+ struct list_head list;
+ struct ir_input_dev *ir_dev;
+ int enabled:1;
+
+ /* State machine control */
+ enum rc5_state state;
+ struct rc5_code rc5_code;
+ unsigned n_half;
+ 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 = "rc5_decoder",
+ .attrs = decoder_attributes,
+};
+
+/**
+ * handle_event() - Decode one RC-5 pulse or space
+ * @input_dev: the struct input_dev descriptor of the device
+ * @ev: event array with type/duration of pulse/space
+ *
+ * This function returns -EINVAL if the pulse violates the state machine
+ */
+static int handle_event(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);
+ int bit, last_bit, n_half;
+
+ data = get_decoder_data(ir_dev);
+ if (!data)
+ return -EINVAL;
+
+ /* Except for the initial event, what matters is the previous bit */
+ bit = (ev->type & IR_PULSE) ? 1 : 0;
+
+ last_bit = !bit;
+
+ /* Discards spurious space last_bits when inactive */
+
+ /* Very long delays are considered as start events */
+ if (ev->delta.tv_nsec > RC5_DURATION + RC5_HALFBIT / 2)
+ data->state = STATE_INACTIVE;
+
+ if (ev->type & IR_START_EVENT)
+ data->state = STATE_INACTIVE;
+
+ switch (data->state) {
+ case STATE_INACTIVE:
+IR_dprintk(1, "currently inative. Received bit (%s) @%luus\n",
+ last_bit ? "pulse" : "space",
+ (ev->delta.tv_nsec + 500) / 1000);
+
+ /* Discards the initial start space */
+ if (bit)
+ return 0;
+ data->count = 0;
+ data->n_half = 0;
+ memset (&data->rc5_code, 0, sizeof(data->rc5_code));
+
+ data->state = STATE_START2_SPACE;
+ return 0;
+ case STATE_START2_SPACE:
+ if (last_bit)
+ goto err;
+ if (!is_rc5_halfbit(ev->delta.tv_nsec))
+ goto err;
+ data->state = STATE_START2_MARK;
+ return 0;
+ case STATE_START2_MARK:
+ if (!last_bit)
+ goto err;
+
+ if (!is_rc5_halfbit(ev->delta.tv_nsec))
+ goto err;
+
+ data->state = STATE_MARKSPACE;
+ return 0;
+ case STATE_MARKSPACE:
+ n_half = n_half(ev->delta.tv_nsec);
+ if (n_half < 1 || n_half > 3) {
+ IR_dprintk(1, "Decode failed at %d-th bit (%s) @%luus\n",
+ data->count,
+ last_bit ? "pulse" : "space",
+ (ev->delta.tv_nsec + 500) / 1000);
+printk("%d halves\n", n_half);
+ goto err2;
+ }
+ data->n_half += n_half;
+
+ if (!last_bit)
+ return 0;
+
+ /* Got one complete mark/space cycle */
+
+ bit = ((data->count + 1) * 2)/ data->n_half;
+
+printk("%d halves, %d bits\n", n_half, bit);
+
+#if 1 /* SANITY check - while testing the decoder */
+ if (bit > 1) {
+ IR_dprintk(1, "Decoder HAS failed at %d-th bit (%s) @%luus\n",
+ data->count,
+ last_bit ? "pulse" : "space",
+ (ev->delta.tv_nsec + 500) / 1000);
+
+ goto err2;
+ }
+#endif
+ /* Ok, we've got a valid bit. proccess it */
+ if (bit) {
+ int shift = data->count;
+
+ /*
+ * RC-5 transmit bytes on this temporal order:
+ * address | not address | command | not command
+ */
+ if (shift < 8) {
+ data->rc5_code.address |= 1 << shift;
+ } else {
+ data->rc5_code.command |= 1 << (shift - 8);
+ }
+ }
+ IR_dprintk(1, "RC-5: bit #%d: %d (%d)\n",
+ data->count, bit, data->n_half);
+ if (++data->count >= RC5_NBITS) {
+ u32 scancode;
+ scancode = data->rc5_code.address << 8 |
+ data->rc5_code.command;
+ IR_dprintk(1, "RC-5 scancode 0x%04x\n", scancode);
+
+ ir_keydown(input_dev, scancode, 0);
+
+ data->state = STATE_TRAILER_MARK;
+ }
+ return 0;
+ case STATE_TRAILER_MARK:
+ if (!last_bit)
+ goto err;
+ data->state = STATE_INACTIVE;
+ return 0;
+ }
+
+err:
+ IR_dprintk(1, "RC-5 decoded failed at state %s (%s) @ %luus\n",
+ st_name[data->state],
+ bit ? "pulse" : "space",
+ (ev->delta.tv_nsec + 500) / 1000);
+err2:
+ data->state = STATE_INACTIVE;
+ return -EINVAL;
+}
+
+/**
+ * ir_rc5_decode() - Decodes all RC-5 pulsecodes on a given array
+ * @input_dev: the struct input_dev descriptor of the device
+ * @evs: event array with type/duration of pulse/space
+ * @len: length of the array
+ * This function returns the number of decoded pulses
+ */
+static int ir_rc5_decode(struct input_dev *input_dev,
+ struct ir_raw_event *evs,
+ int len)
+{
+ struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
+ struct decoder_data *data;
+ int pos = 0;
+ int rc = 0;
+
+ data = get_decoder_data(ir_dev);
+ if (!data || !data->enabled)
+ return 0;
+
+ for (pos = 0; pos < len; pos++)
+ handle_event(input_dev, &evs[pos]);
+
+ return rc;
+}
+
+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 RC-5 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("RC-5 IR protocol decoder");
projects / GitHub / MotorolaMobilityLLC / kernel-slsi.git / commitdiff