1 files changed, 244 insertions, 0 deletions
diff --git a/drivers/media/rc/ir-sharp-decoder.c b/drivers/media/rc/ir-sharp-decoder.c
new file mode 100644
index 0000000000..3311099cbd
--- /dev/null
+++ b/drivers/media/rc/ir-sharp-decoder.c
@@ -0,0 +1,244 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* 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
+ */
+
+#include <linux/bitrev.h>
+#include <linux/module.h>
+#include "rc-core-priv.h"
+
+#define SHARP_NBITS		15
+#define SHARP_UNIT		40  /* us */
+#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 (1680us space) */
+#define SHARP_BIT_0_SPACE	(17   * SHARP_UNIT) /* 680us space */
+#define SHARP_BIT_1_SPACE	(42   * SHARP_UNIT) /* 1680us 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
+ * @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_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 (!is_timing_event(ev)) {
+		if (ev.overflow)
+			data->state = STATE_INACTIVE;
+		return 0;
+	}
+
+	dev_dbg(&dev->dev, "Sharp decode started at state %d (%uus %s)\n",
+		data->state, 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 &&
+			/* DENON variant, both chk bits 0 */
+			    (data->bits & 0x3) != 0x0)
+				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) {
+			dev_dbg(&dev->dev,
+				"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;
+		dev_dbg(&dev->dev, "Sharp scancode 0x%04x\n", scancode);
+
+		rc_keydown(dev, RC_PROTO_SHARP, scancode, 0);
+		data->state = STATE_INACTIVE;
+		return 0;
+	}
+
+	dev_dbg(&dev->dev, "Sharp decode failed at count %d state %d (%uus %s)\n",
+		data->count, data->state, ev.duration, TO_STR(ev.pulse));
+	data->state = STATE_INACTIVE;
+	return -EINVAL;
+}
+
+static const struct ir_raw_timings_pd ir_sharp_timings = {
+	.header_pulse  = 0,
+	.header_space  = 0,
+	.bit_pulse     = SHARP_BIT_PULSE,
+	.bit_space[0]  = SHARP_BIT_0_SPACE,
+	.bit_space[1]  = SHARP_BIT_1_SPACE,
+	.trailer_pulse = SHARP_BIT_PULSE,
+	.trailer_space = SHARP_ECHO_SPACE,
+	.msb_first     = 1,
+};
+
+/**
+ * ir_sharp_encode() - Encode a scancode as a stream of raw events
+ *
+ * @protocol:	protocol to encode
+ * @scancode:	scancode to encode
+ * @events:	array of raw ir events to write into
+ * @max:	maximum size of @events
+ *
+ * Returns:	The number of events written.
+ *		-ENOBUFS if there isn't enough space in the array to fit the
+ *		encoding. In this case all @max events will have been written.
+ */
+static int ir_sharp_encode(enum rc_proto protocol, u32 scancode,
+			   struct ir_raw_event *events, unsigned int max)
+{
+	struct ir_raw_event *e = events;
+	int ret;
+	u32 raw;
+
+	raw = (((bitrev8(scancode >> 8) >> 3) << 8) & 0x1f00) |
+		bitrev8(scancode);
+	ret = ir_raw_gen_pd(&e, max, &ir_sharp_timings, SHARP_NBITS,
+			    (raw << 2) | 2);
+	if (ret < 0)
+		return ret;
+
+	max -= ret;
+
+	raw = (((bitrev8(scancode >> 8) >> 3) << 8) & 0x1f00) |
+		bitrev8(~scancode);
+	ret = ir_raw_gen_pd(&e, max, &ir_sharp_timings, SHARP_NBITS,
+			    (raw << 2) | 1);
+	if (ret < 0)
+		return ret;
+
+	return e - events;
+}
+
+static struct ir_raw_handler sharp_handler = {
+	.protocols	= RC_PROTO_BIT_SHARP,
+	.decode		= ir_sharp_decode,
+	.encode		= ir_sharp_encode,
+	.carrier	= 38000,
+	.min_timeout	= SHARP_ECHO_SPACE + SHARP_ECHO_SPACE / 4,
+};
+
+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 <jhogan@kernel.org>");
+MODULE_DESCRIPTION("Sharp IR protocol decoder");