--- /dev/null
+/* ir-rc5-decoder.c - decoder for RC5(x) and StreamZap protocols
+ *
+ * Copyright (C) 2010 by Mauro Carvalho Chehab
+ * Copyright (C) 2010 by Jarod Wilson <jarod@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 decoder handles the 14 bit RC5 protocol, 15 bit "StreamZap" protocol
+ * and 20 bit RC5x protocol.
+ */
+
+#include "rc-core-priv.h"
+#include <linux/module.h>
+
+#define RC5_NBITS 14
+#define RC5_SZ_NBITS 15
+#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)
+#define RC5_TRAILER (10 * RC5_UNIT) /* In reality, approx 100 */
+
+enum rc5_state {
+ STATE_INACTIVE,
+ STATE_BIT_START,
+ STATE_BIT_END,
+ STATE_CHECK_RC5X,
+ STATE_FINISHED,
+};
+
+/**
+ * ir_rc5_decode() - Decode one RC-5 pulse or space
+ * @dev: the struct rc_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 rc_dev *dev, struct ir_raw_event ev)
+{
+ struct rc5_dec *data = &dev->raw->rc5;
+ u8 toggle;
+ u32 scancode;
+ enum rc_type protocol;
+
+ if (!(dev->enabled_protocols & (RC_BIT_RC5 | RC_BIT_RC5X | RC_BIT_RC5_SZ)))
+ return 0;
+
+ if (!is_timing_event(ev)) {
+ if (ev.reset)
+ data->state = STATE_INACTIVE;
+ return 0;
+ }
+
+ if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2))
+ goto out;
+
+again:
+ IR_dprintk(2, "RC5(x/sz) 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;
+ decrease_duration(&ev, RC5_BIT_START);
+ goto again;
+
+ case STATE_BIT_START:
+ if (!ev.pulse && geq_margin(ev.duration, RC5_TRAILER, RC5_UNIT / 2)) {
+ data->state = STATE_FINISHED;
+ goto again;
+ }
+
+ if (!eq_margin(ev.duration, RC5_BIT_START, RC5_UNIT / 2))
+ break;
+
+ data->bits <<= 1;
+ if (!ev.pulse)
+ data->bits |= 1;
+ data->count++;
+ data->state = STATE_BIT_END;
+ return 0;
+
+ case STATE_BIT_END:
+ if (!is_transition(&ev, &dev->raw->prev_ev))
+ break;
+
+ 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)) {
+ data->is_rc5x = true;
+ decrease_duration(&ev, RC5X_SPACE);
+ } else
+ data->is_rc5x = false;
+ data->state = STATE_BIT_START;
+ goto again;
+
+ case STATE_FINISHED:
+ if (ev.pulse)
+ break;
+
+ if (data->is_rc5x && data->count == RC5X_NBITS) {
+ /* RC5X */
+ u8 xdata, command, system;
+ if (!(dev->enabled_protocols & RC_BIT_RC5X)) {
+ data->state = STATE_INACTIVE;
+ return 0;
+ }
+ xdata = (data->bits & 0x0003F) >> 0;
+ command = (data->bits & 0x00FC0) >> 6;
+ system = (data->bits & 0x1F000) >> 12;
+ toggle = (data->bits & 0x20000) ? 1 : 0;
+ command += (data->bits & 0x01000) ? 0 : 0x40;
+ scancode = system << 16 | command << 8 | xdata;
+ protocol = RC_TYPE_RC5X;
+
+ } else if (!data->is_rc5x && data->count == RC5_NBITS) {
+ /* RC5 */
+ u8 command, system;
+ if (!(dev->enabled_protocols & RC_BIT_RC5)) {
+ data->state = STATE_INACTIVE;
+ return 0;
+ }
+ command = (data->bits & 0x0003F) >> 0;
+ system = (data->bits & 0x007C0) >> 6;
+ toggle = (data->bits & 0x00800) ? 1 : 0;
+ command += (data->bits & 0x01000) ? 0 : 0x40;
+ scancode = system << 8 | command;
+ protocol = RC_TYPE_RC5;
+
+ } else if (!data->is_rc5x && data->count == RC5_SZ_NBITS) {
+ /* RC5 StreamZap */
+ u8 command, system;
+ if (!(dev->enabled_protocols & RC_BIT_RC5_SZ)) {
+ data->state = STATE_INACTIVE;
+ return 0;
+ }
+ command = (data->bits & 0x0003F) >> 0;
+ system = (data->bits & 0x02FC0) >> 6;
+ toggle = (data->bits & 0x01000) ? 1 : 0;
+ scancode = system << 6 | command;
+ protocol = RC_TYPE_RC5_SZ;
+
+ } else
+ break;
+
+ IR_dprintk(1, "RC5(x/sz) scancode 0x%06x (p: %u, t: %u)\n",
+ scancode, protocol, toggle);
+
+ rc_keydown(dev, protocol, scancode, toggle);
+ data->state = STATE_INACTIVE;
+ return 0;
+ }
+
+out:
+ IR_dprintk(1, "RC5(x/sz) decode failed at state %i count %d (%uus %s)\n",
+ data->state, data->count, TO_US(ev.duration), TO_STR(ev.pulse));
+ data->state = STATE_INACTIVE;
+ return -EINVAL;
+}
+
+static struct ir_raw_handler rc5_handler = {
+ .protocols = RC_BIT_RC5 | RC_BIT_RC5X | RC_BIT_RC5_SZ,
+ .decode = ir_rc5_decode,
+};
+
+static int __init ir_rc5_decode_init(void)
+{
+ ir_raw_handler_register(&rc5_handler);
+
+ printk(KERN_INFO "IR RC5(x/sz) 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 and Jarod Wilson");
+MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
+MODULE_DESCRIPTION("RC5(x/sz) IR protocol decoder");
Code Review / kvmfornfv.git / blobdiff