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path: root/drivers/media/IR/ir-rc5-decoder.c
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Diffstat (limited to 'drivers/media/IR/ir-rc5-decoder.c')
-rw-r--r--drivers/media/IR/ir-rc5-decoder.c324
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");
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-21 17:48:10 +0300