[PATCH 2/2] media: mtk-cir: remove superfluous ir_raw_event_reset()

[Sean Young]

This IR receiver has two limitations:

1) Any IR pulse or space longer than 12ms will be truncated 12ms

2) Any pulses/spaces after the first 68 are lost

ir_raw_event_reset() won't help here. If the IR cannot be decoded, any
decoder should reset itself, and if it does not, this is a bug in the
decoder.

Cc: Sean Wang <sean.wang at mediatek.com>
Cc: Matthias Brugger <matthias.bgg at gmail.com>
Signed-off-by: Sean Young <sean at mess.org>
---
 drivers/media/rc/mtk-cir.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/drivers/media/rc/mtk-cir.c b/drivers/media/rc/mtk-cir.c
index 746d43fdc17a..255f8a116b59 100644
--- a/drivers/media/rc/mtk-cir.c
+++ b/drivers/media/rc/mtk-cir.c
@@ -209,19 +209,18 @@ static irqreturn_t mtk_ir_irq(int irqno, void *dev_id)
 	struct ir_raw_event rawir = {};
 
 	/*
-	 * Reset decoder state machine explicitly is required
-	 * because 1) the longest duration for space MTK IR hardware
-	 * could record is not safely long. e.g  12ms if rx resolution
-	 * is 46us by default. There is still the risk to satisfying
-	 * every decoder to reset themselves through long enough
-	 * trailing spaces and 2) the IRQ handler guarantees that
-	 * start of IR message is always contained in and starting
-	 * from register mtk_chkdata_reg(ir, i).
+	 * Each pulse and space is encoded as a single byte, each byte
+	 * alternating between pulse and space. If a pulse or space is longer
+	 * than can be encoded in a single byte, it is encoded as the maximum
+	 * value 0xff.
+	 *
+	 * If a space is longer ok_count (about 23ms), the value is encoded
+	 * as zero, and all following values are zero. Any IR that follows
+	 * will be presented in the next interrupt.
+	 *
+	 * If there are more than 68 (=MTK_CHKDATA_SZ * 4) pulses and spaces,
+	 * then the only the first 68 will be presented; the rest is lost.
 	 */
-	ir_raw_event_reset(ir->rc);
-
-	/* First message must be pulse */
-	rawir.pulse = false;
 
 	/* Handle all pulse and space IR controller captures */
 	for (i = 0 ; i < MTK_CHKDATA_SZ ; i++) {
-- 
2.34.1