media: rc: harmonize infrared durations to microseconds

rc-core kapi uses nanoseconds for infrared durations for receiving, and
microseconds for sending. The uapi already uses microseconds for both,
so this patch does not change the uapi.

Infrared durations do not need nanosecond resolution. IR protocols do not
have durations shorter than about 100 microseconds. Some IR hardware offers
250 microseconds resolution, which is sufficient for most protocols.
Better hardware has 50 microsecond resolution and is enough for every
protocol I am aware off.

Unify on microseconds everywhere. This simplifies the code since less
conversion between microseconds and nanoseconds needs to be done.

This affects:
 - rx_resolution member of struct rc_dev
 - timeout member of struct rc_dev
 - duration member in struct ir_raw_event

Cc: "Bruno Prémont" <bonbons@linux-vserver.org>
Cc: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: Maxim Levitsky <maximlevitsky@gmail.com>
Cc: Patrick Lerda <patrick9876@free.fr>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Jerome Brunet <jbrunet@baylibre.com>
Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: Sean Wang <sean.wang@mediatek.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: "David Härdeman" <david@hardeman.nu>
Cc: Benjamin Valentin <benpicco@googlemail.com>
Cc: Antti Palosaari <crope@iki.fi>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

1 files changed, 9 insertions, 9 deletions

diff --git a/drivers/media/rc/ttusbir.c b/drivers/media/rc/ttusbir.c
index 011a8b620d86..629787d53ee1 100644
--- a/drivers/media/rc/ttusbir.c
+++ b/drivers/media/rc/ttusbir.c
@@ -20,8 +20,8 @@
  * messages per second (!), whether IR is idle or not.
  */
 #define NUM_URBS	4
-#define NS_PER_BYTE	62500
-#define NS_PER_BIT	(NS_PER_BYTE/8)
+#define US_PER_BYTE	62
+#define US_PER_BIT	(US_PER_BYTE / 8)
 
 struct ttusbir {
 	struct rc_dev *rc;
@@ -117,13 +117,13 @@ static void ttusbir_process_ir_data(struct ttusbir *tt, uint8_t *buf)
 		switch (v) {
 		case 0xfe:
 			rawir.pulse = false;
-			rawir.duration = NS_PER_BYTE;
+			rawir.duration = US_PER_BYTE;
 			if (ir_raw_event_store_with_filter(tt->rc, &rawir))
 				event = true;
 			break;
 		case 0:
 			rawir.pulse = true;
-			rawir.duration = NS_PER_BYTE;
+			rawir.duration = US_PER_BYTE;
 			if (ir_raw_event_store_with_filter(tt->rc, &rawir))
 				event = true;
 			break;
@@ -137,12 +137,12 @@ static void ttusbir_process_ir_data(struct ttusbir *tt, uint8_t *buf)
 				rawir.pulse = false;
 			}
 
-			rawir.duration = NS_PER_BIT * (8 - b);
+			rawir.duration = US_PER_BIT * (8 - b);
 			if (ir_raw_event_store_with_filter(tt->rc, &rawir))
 				event = true;
 
 			rawir.pulse = !rawir.pulse;
-			rawir.duration = NS_PER_BIT * b;
+			rawir.duration = US_PER_BIT * b;
 			if (ir_raw_event_store_with_filter(tt->rc, &rawir))
 				event = true;
 			break;
@@ -311,10 +311,10 @@ static int ttusbir_probe(struct usb_interface *intf,
 	rc->max_timeout = 10 * IR_DEFAULT_TIMEOUT;
 
 	/*
-	 * The precision is NS_PER_BIT, but since every 8th bit can be
-	 * overwritten with garbage the accuracy is at best 2 * NS_PER_BIT.
+	 * The precision is US_PER_BIT, but since every 8th bit can be
+	 * overwritten with garbage the accuracy is at best 2 * US_PER_BIT.
 	 */
-	rc->rx_resolution = NS_PER_BIT;
+	rc->rx_resolution = 2 * US_PER_BIT;
 
 	ret = rc_register_device(rc);
 	if (ret) {