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-rw-r--r--drivers/media/rc/ir-rc5-sz-decoder.c153
1 files changed, 153 insertions, 0 deletions
diff --git a/drivers/media/rc/ir-rc5-sz-decoder.c b/drivers/media/rc/ir-rc5-sz-decoder.c
new file mode 100644
index 00000000000..90aa8868629
--- /dev/null
+++ b/drivers/media/rc/ir-rc5-sz-decoder.c
@@ -0,0 +1,153 @@
+/* ir-rc5-sz-decoder.c - handle RC5 Streamzap IR Pulse/Space protocol
+ *
+ * Copyright (C) 2010 by Mauro Carvalho Chehab <mchehab@redhat.com>
+ * 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 code handles the 15 bit RC5-ish protocol used by the Streamzap
+ * PC Remote.
+ * It considers a carrier of 36 kHz, with a total of 15 bits, where
+ * the first two bits are start bits, and a third one is a filing bit
+ */
+
+#include "rc-core-priv.h"
+
+#define RC5_SZ_NBITS 15
+#define RC5_UNIT 888888 /* ns */
+#define RC5_BIT_START (1 * RC5_UNIT)
+#define RC5_BIT_END (1 * RC5_UNIT)
+
+enum rc5_sz_state {
+ STATE_INACTIVE,
+ STATE_BIT_START,
+ STATE_BIT_END,
+ STATE_FINISHED,
+};
+
+/**
+ * ir_rc5_sz_decode() - Decode one RC-5 Streamzap 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_sz_decode(struct rc_dev *dev, struct ir_raw_event ev)
+{
+ struct rc5_sz_dec *data = &dev->raw->rc5_sz;
+ u8 toggle, command, system;
+ u32 scancode;
+
+ if (!(dev->raw->enabled_protocols & RC_TYPE_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-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;
+ data->wanted_bits = RC5_SZ_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->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 == data->wanted_bits)
+ data->state = STATE_FINISHED;
+ else
+ data->state = STATE_BIT_START;
+
+ decrease_duration(&ev, RC5_BIT_END);
+ goto again;
+
+ case STATE_FINISHED:
+ if (ev.pulse)
+ break;
+
+ /* RC5-sz */
+ command = (data->bits & 0x0003F) >> 0;
+ system = (data->bits & 0x02FC0) >> 6;
+ toggle = (data->bits & 0x01000) ? 1 : 0;
+ scancode = system << 6 | command;
+
+ IR_dprintk(1, "RC5-sz scancode 0x%04x (toggle: %u)\n",
+ scancode, toggle);
+
+ rc_keydown(dev, scancode, toggle);
+ data->state = STATE_INACTIVE;
+ return 0;
+ }
+
+out:
+ IR_dprintk(1, "RC5-sz 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 struct ir_raw_handler rc5_sz_handler = {
+ .protocols = RC_TYPE_RC5_SZ,
+ .decode = ir_rc5_sz_decode,
+};
+
+static int __init ir_rc5_sz_decode_init(void)
+{
+ ir_raw_handler_register(&rc5_sz_handler);
+
+ printk(KERN_INFO "IR RC5 (streamzap) protocol handler initialized\n");
+ return 0;
+}
+
+static void __exit ir_rc5_sz_decode_exit(void)
+{
+ ir_raw_handler_unregister(&rc5_sz_handler);
+}
+
+module_init(ir_rc5_sz_decode_init);
+module_exit(ir_rc5_sz_decode_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jarod Wilson <jarod@redhat.com>");
+MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
+MODULE_DESCRIPTION("RC5 (streamzap) IR protocol decoder");