1 files changed, 280 insertions, 0 deletions

diff --git a/drivers/media/rc/ir-rc6-decoder.c b/drivers/media/rc/ir-rc6-decoder.c
new file mode 100644
index 000000000000..755dafa3871b
--- /dev/null
+++ b/drivers/media/rc/ir-rc6-decoder.c
@@ -0,0 +1,280 @@
+/* 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 "rc-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        (6 * RC6_UNIT)
+#define RC6_PREFIX_SPACE        (2 * RC6_UNIT)
+#define RC6_BIT_START           (1 * RC6_UNIT)
+#define RC6_BIT_END             (1 * RC6_UNIT)
+#define RC6_TOGGLE_START        (2 * RC6_UNIT)
+#define RC6_TOGGLE_END          (2 * RC6_UNIT)
+#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 */
+
+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,
+};
+
+static enum rc6_mode rc6_mode(struct rc6_dec *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
+ * @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_rc6_decode(struct rc_dev *dev, struct ir_raw_event ev)
+{
+        struct rc6_dec *data = &dev->raw->rc6;
+        u32 scancode;
+        u8 toggle;
+
+        if (!(dev->raw->enabled_protocols & RC_TYPE_RC6))
+                return 0;
+
+        if (!is_timing_event(ev)) {
+                if (ev.reset)
+                        data->state = STATE_INACTIVE;
+                return 0;
+        }
+
+        if (!geq_margin(ev.duration, RC6_UNIT, RC6_UNIT / 2))
+                goto out;
+
+again:
+        IR_dprintk(2, "RC6 decode started at state %i (%uus %s)\n",
+                   data->state, TO_US(ev.duration), TO_STR(ev.pulse));
+
+        if (!geq_margin(ev.duration, RC6_UNIT, RC6_UNIT / 2))
+                return 0;
+
+        switch (data->state) {
+
+        case STATE_INACTIVE:
+                if (!ev.pulse)
+                        break;
+
+                /* Note: larger margin on first pulse since each RC6_UNIT
+                   is quite short and some hardware takes some time to
+                   adjust to the signal */
+                if (!eq_margin(ev.duration, RC6_PREFIX_PULSE, RC6_UNIT))
+                        break;
+
+                data->state = STATE_PREFIX_SPACE;
+                data->count = 0;
+                return 0;
+
+        case STATE_PREFIX_SPACE:
+                if (ev.pulse)
+                        break;
+
+                if (!eq_margin(ev.duration, RC6_PREFIX_SPACE, RC6_UNIT / 2))
+                        break;
+
+                data->state = STATE_HEADER_BIT_START;
+                return 0;
+
+        case STATE_HEADER_BIT_START:
+                if (!eq_margin(ev.duration, RC6_BIT_START, RC6_UNIT / 2))
+                        break;
+
+                data->header <<= 1;
+                if (ev.pulse)
+                        data->header |= 1;
+                data->count++;
+                data->state = STATE_HEADER_BIT_END;
+                return 0;
+
+        case STATE_HEADER_BIT_END:
+                if (!is_transition(&ev, &dev->raw->prev_ev))
+                        break;
+
+                if (data->count == RC6_HEADER_NBITS)
+                        data->state = STATE_TOGGLE_START;
+                else
+                        data->state = STATE_HEADER_BIT_START;
+
+                decrease_duration(&ev, RC6_BIT_END);
+                goto again;
+
+        case STATE_TOGGLE_START:
+                if (!eq_margin(ev.duration, RC6_TOGGLE_START, RC6_UNIT / 2))
+                        break;
+
+                data->toggle = ev.pulse;
+                data->state = STATE_TOGGLE_END;
+                return 0;
+
+        case STATE_TOGGLE_END:
+                if (!is_transition(&ev, &dev->raw->prev_ev) ||
+                    !geq_margin(ev.duration, RC6_TOGGLE_END, RC6_UNIT / 2))
+                        break;
+
+                if (!(data->header & RC6_STARTBIT_MASK)) {
+                        IR_dprintk(1, "RC6 invalid start bit\n");
+                        break;
+                }
+
+                data->state = STATE_BODY_BIT_START;
+                decrease_duration(&ev, RC6_TOGGLE_END);
+                data->count = 0;
+
+                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 ((!ev.pulse && !geq_margin(ev.duration, RC6_UNIT, RC6_UNIT / 2)) ||
+                            geq_margin(ev.duration, RC6_UNIT, RC6_UNIT / 2))
+                                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;
+
+        case STATE_BODY_BIT_START:
+                if (!eq_margin(ev.duration, RC6_BIT_START, RC6_UNIT / 2))
+                        break;
+
+                data->body <<= 1;
+                if (ev.pulse)
+                        data->body |= 1;
+                data->count++;
+                data->state = STATE_BODY_BIT_END;
+                return 0;
+
+        case STATE_BODY_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_BODY_BIT_START;
+
+                decrease_duration(&ev, RC6_BIT_END);
+                goto again;
+
+        case STATE_FINISHED:
+                if (ev.pulse)
+                        break;
+
+                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;
+                }
+
+                rc_keydown(dev, scancode, toggle);
+                data->state = STATE_INACTIVE;
+                return 0;
+        }
+
+out:
+        IR_dprintk(1, "RC6 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 rc6_handler = {
+        .protocols      = RC_TYPE_RC6,
+        .decode         = ir_rc6_decode,
+};
+
+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");