--- /dev/null
+/* ir-sharp-decoder.c - handle Sharp IR Pulse/Space protocol
+ *
+ * Copyright (C) 2013-2014 Imagination Technologies Ltd.
+ *
+ * Based on NEC decoder:
+ * Copyright (C) 2010 by Mauro Carvalho Chehab
+ *
+ * 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 <linux/bitrev.h>
+#include <linux/module.h>
+#include "rc-core-priv.h"
+
+#define SHARP_NBITS 15
+#define SHARP_UNIT 40000 /* ns */
+#define SHARP_BIT_PULSE (8 * SHARP_UNIT) /* 320us */
+#define SHARP_BIT_0_PERIOD (25 * SHARP_UNIT) /* 1ms (680us space) */
+#define SHARP_BIT_1_PERIOD (50 * SHARP_UNIT) /* 2ms (1680ms space) */
+#define SHARP_ECHO_SPACE (1000 * SHARP_UNIT) /* 40 ms */
+#define SHARP_TRAILER_SPACE (125 * SHARP_UNIT) /* 5 ms (even longer) */
+
+enum sharp_state {
+ STATE_INACTIVE,
+ STATE_BIT_PULSE,
+ STATE_BIT_SPACE,
+ STATE_TRAILER_PULSE,
+ STATE_ECHO_SPACE,
+ STATE_TRAILER_SPACE,
+};
+
+/**
+ * ir_sharp_decode() - Decode one Sharp pulse or space
+ * @dev: the struct rc_dev descriptor of the device
+ * @duration: the struct ir_raw_event descriptor of the pulse/space
+ *
+ * This function returns -EINVAL if the pulse violates the state machine
+ */
+static int ir_sharp_decode(struct rc_dev *dev, struct ir_raw_event ev)
+{
+ struct sharp_dec *data = &dev->raw->sharp;
+ u32 msg, echo, address, command, scancode;
+
+ if (!(dev->enabled_protocols & RC_BIT_SHARP))
+ return 0;
+
+ if (!is_timing_event(ev)) {
+ if (ev.reset)
+ data->state = STATE_INACTIVE;
+ return 0;
+ }
+
+ IR_dprintk(2, "Sharp decode started at state %d (%uus %s)\n",
+ data->state, TO_US(ev.duration), TO_STR(ev.pulse));
+
+ switch (data->state) {
+
+ case STATE_INACTIVE:
+ if (!ev.pulse)
+ break;
+
+ if (!eq_margin(ev.duration, SHARP_BIT_PULSE,
+ SHARP_BIT_PULSE / 2))
+ break;
+
+ data->count = 0;
+ data->pulse_len = ev.duration;
+ data->state = STATE_BIT_SPACE;
+ return 0;
+
+ case STATE_BIT_PULSE:
+ if (!ev.pulse)
+ break;
+
+ if (!eq_margin(ev.duration, SHARP_BIT_PULSE,
+ SHARP_BIT_PULSE / 2))
+ break;
+
+ data->pulse_len = ev.duration;
+ data->state = STATE_BIT_SPACE;
+ return 0;
+
+ case STATE_BIT_SPACE:
+ if (ev.pulse)
+ break;
+
+ data->bits <<= 1;
+ if (eq_margin(data->pulse_len + ev.duration, SHARP_BIT_1_PERIOD,
+ SHARP_BIT_PULSE * 2))
+ data->bits |= 1;
+ else if (!eq_margin(data->pulse_len + ev.duration,
+ SHARP_BIT_0_PERIOD, SHARP_BIT_PULSE * 2))
+ break;
+ data->count++;
+
+ if (data->count == SHARP_NBITS ||
+ data->count == SHARP_NBITS * 2)
+ data->state = STATE_TRAILER_PULSE;
+ else
+ data->state = STATE_BIT_PULSE;
+
+ return 0;
+
+ case STATE_TRAILER_PULSE:
+ if (!ev.pulse)
+ break;
+
+ if (!eq_margin(ev.duration, SHARP_BIT_PULSE,
+ SHARP_BIT_PULSE / 2))
+ break;
+
+ if (data->count == SHARP_NBITS) {
+ /* exp,chk bits should be 1,0 */
+ if ((data->bits & 0x3) != 0x2)
+ break;
+ data->state = STATE_ECHO_SPACE;
+ } else {
+ data->state = STATE_TRAILER_SPACE;
+ }
+ return 0;
+
+ case STATE_ECHO_SPACE:
+ if (ev.pulse)
+ break;
+
+ if (!eq_margin(ev.duration, SHARP_ECHO_SPACE,
+ SHARP_ECHO_SPACE / 4))
+ break;
+
+ data->state = STATE_BIT_PULSE;
+
+ return 0;
+
+ case STATE_TRAILER_SPACE:
+ if (ev.pulse)
+ break;
+
+ if (!geq_margin(ev.duration, SHARP_TRAILER_SPACE,
+ SHARP_BIT_PULSE / 2))
+ break;
+
+ /* Validate - command, ext, chk should be inverted in 2nd */
+ msg = (data->bits >> 15) & 0x7fff;
+ echo = data->bits & 0x7fff;
+ if ((msg ^ echo) != 0x3ff) {
+ IR_dprintk(1,
+ "Sharp checksum error: received 0x%04x, 0x%04x\n",
+ msg, echo);
+ break;
+ }
+
+ address = bitrev8((msg >> 7) & 0xf8);
+ command = bitrev8((msg >> 2) & 0xff);
+
+ scancode = address << 8 | command;
+ IR_dprintk(1, "Sharp scancode 0x%04x\n", scancode);
+
+ rc_keydown(dev, RC_TYPE_SHARP, scancode, 0);
+ data->state = STATE_INACTIVE;
+ return 0;
+ }
+
+ IR_dprintk(1, "Sharp decode failed at count %d state %d (%uus %s)\n",
+ data->count, data->state, TO_US(ev.duration),
+ TO_STR(ev.pulse));
+ data->state = STATE_INACTIVE;
+ return -EINVAL;
+}
+
+static struct ir_raw_handler sharp_handler = {
+ .protocols = RC_BIT_SHARP,
+ .decode = ir_sharp_decode,
+};
+
+static int __init ir_sharp_decode_init(void)
+{
+ ir_raw_handler_register(&sharp_handler);
+
+ pr_info("IR Sharp protocol handler initialized\n");
+ return 0;
+}
+
+static void __exit ir_sharp_decode_exit(void)
+{
+ ir_raw_handler_unregister(&sharp_handler);
+}
+
+module_init(ir_sharp_decode_init);
+module_exit(ir_sharp_decode_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("James Hogan <james.hogan@imgtec.com>");
+MODULE_DESCRIPTION("Sharp IR protocol decoder");
Code Review / kvmfornfv.git / blobdiff