[PATCH 1/2] media: mtk-cir: reduce message end to fix nec repeats

[PATCH 1/2] media: mtk-cir: reduce message end to fix nec repeats

[Sean Young]

The ir receiver generates an interrupt with the IR data, once a space of
at least ok_count is has been seen. Currently this is about 110ms; when
holding down a button on a nec remote, no such space is generated until
a button is released. This means nothing happens until you release the
button.

The sample rate is fixed at 46us, so the maximum space that can be
encoded is about 12ms. So, the set ok_count above that at 23ms.

Cc: Sean Wang <sean.wang@mediatek.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Sean Young <sean@mess.org>
---
 drivers/media/rc/mtk-cir.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/media/rc/mtk-cir.c b/drivers/media/rc/mtk-cir.c
index 840e7aec5c21..746d43fdc17a 100644
--- a/drivers/media/rc/mtk-cir.c
+++ b/drivers/media/rc/mtk-cir.c
@@ -24,7 +24,8 @@
  * Register to setting ok count whose unit based on hardware sampling period
  * indicating IR receiving completion and then making IRQ fires
  */
-#define MTK_OK_COUNT(x)		  (((x) & GENMASK(23, 16)) << 16)
+#define MTK_OK_COUNT_MASK	  (GENMASK(22, 16))
+#define MTK_OK_COUNT(x)		  ((x) << 16)
 
 /* Bit to enable IR hardware function */
 #define MTK_IR_EN		  BIT(0)
@@ -268,7 +269,7 @@ static irqreturn_t mtk_ir_irq(int irqno, void *dev_id)
 static const struct mtk_ir_data mt7623_data = {
 	.regs = mt7623_regs,
 	.fields = mt7623_fields,
-	.ok_count = 0xf,
+	.ok_count = 3,
 	.hw_period = 0xff,
 	.div	= 4,
 };
@@ -276,7 +277,7 @@ static const struct mtk_ir_data mt7623_data = {
 static const struct mtk_ir_data mt7622_data = {
 	.regs = mt7622_regs,
 	.fields = mt7622_fields,
-	.ok_count = 0xf,
+	.ok_count = 3,
 	.hw_period = 0xffff,
 	.div	= 32,
 };
@@ -400,7 +401,7 @@ static int mtk_ir_probe(struct platform_device *pdev)
 	mtk_w32_mask(ir, MTK_DG_CNT(1), MTK_DG_CNT_MASK, MTK_IRTHD);
 
 	/* Enable IR and PWM */
-	val = mtk_r32(ir, MTK_CONFIG_HIGH_REG);
+	val = mtk_r32(ir, MTK_CONFIG_HIGH_REG) & ~MTK_OK_COUNT_MASK;
 	val |= MTK_OK_COUNT(ir->data->ok_count) |  MTK_PWM_EN | MTK_IR_EN;
 	mtk_w32(ir, val, MTK_CONFIG_HIGH_REG);
 
-- 
2.34.1

[PATCH 1/2] media: mtk-cir: reduce message end to fix nec repeats

[Sean Young]

The ir receiver generates an interrupt with the IR data, once a space of
at least ok_count is has been seen. Currently this is about 110ms; when
holding down a button on a nec remote, no such space is generated until
a button is released. This means nothing happens until you release the
button.

The sample rate is fixed at 46us, so the maximum space that can be
encoded is about 12ms. So, the set ok_count above that at 23ms.

Cc: Sean Wang <sean.wang@mediatek.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Sean Young <sean@mess.org>
---
 drivers/media/rc/mtk-cir.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/media/rc/mtk-cir.c b/drivers/media/rc/mtk-cir.c
index 840e7aec5c21..746d43fdc17a 100644
--- a/drivers/media/rc/mtk-cir.c
+++ b/drivers/media/rc/mtk-cir.c
@@ -24,7 +24,8 @@
  * Register to setting ok count whose unit based on hardware sampling period
  * indicating IR receiving completion and then making IRQ fires
  */
-#define MTK_OK_COUNT(x)		  (((x) & GENMASK(23, 16)) << 16)
+#define MTK_OK_COUNT_MASK	  (GENMASK(22, 16))
+#define MTK_OK_COUNT(x)		  ((x) << 16)
 
 /* Bit to enable IR hardware function */
 #define MTK_IR_EN		  BIT(0)
@@ -268,7 +269,7 @@ static irqreturn_t mtk_ir_irq(int irqno, void *dev_id)
 static const struct mtk_ir_data mt7623_data = {
 	.regs = mt7623_regs,
 	.fields = mt7623_fields,
-	.ok_count = 0xf,
+	.ok_count = 3,
 	.hw_period = 0xff,
 	.div	= 4,
 };
@@ -276,7 +277,7 @@ static const struct mtk_ir_data mt7623_data = {
 static const struct mtk_ir_data mt7622_data = {
 	.regs = mt7622_regs,
 	.fields = mt7622_fields,
-	.ok_count = 0xf,
+	.ok_count = 3,
 	.hw_period = 0xffff,
 	.div	= 32,
 };
@@ -400,7 +401,7 @@ static int mtk_ir_probe(struct platform_device *pdev)
 	mtk_w32_mask(ir, MTK_DG_CNT(1), MTK_DG_CNT_MASK, MTK_IRTHD);
 
 	/* Enable IR and PWM */
-	val = mtk_r32(ir, MTK_CONFIG_HIGH_REG);
+	val = mtk_r32(ir, MTK_CONFIG_HIGH_REG) & ~MTK_OK_COUNT_MASK;
 	val |= MTK_OK_COUNT(ir->data->ok_count) |  MTK_PWM_EN | MTK_IR_EN;
 	mtk_w32(ir, val, MTK_CONFIG_HIGH_REG);
 
-- 
2.34.1


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[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@mediatek.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Sean Young <sean@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

[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@mediatek.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Sean Young <sean@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


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