media: cec-pin: improve status log

Keep track of the number of short or long start bits, the number
of short or long data bits and the number of initiated or detected
low drive conditions.

Show this information in the status debugfs log.

Helpful when debugging, particularly when doing error injection
as well.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

1 files changed, 55 insertions, 3 deletions

diff --git a/drivers/media/cec/cec-pin.c b/drivers/media/cec/cec-pin.c
index d03ed4eefdd6..da8c514c657d 100644
--- a/drivers/media/cec/cec-pin.c
+++ b/drivers/media/cec/cec-pin.c
@@ -432,6 +432,7 @@ static void cec_pin_tx_states(struct cec_pin *pin, ktime_t ts)
 			pin->state = CEC_ST_TX_WAIT_FOR_HIGH;
 			pin->work_tx_ts = ts;
 			pin->work_tx_status = CEC_TX_STATUS_LOW_DRIVE;
+			pin->tx_low_drive_cnt++;
 			wake_up_interruptible(&pin->kthread_waitq);
 			break;
 		}
@@ -463,6 +464,7 @@ static void cec_pin_tx_states(struct cec_pin *pin, ktime_t ts)
 				break;
 			pin->work_tx_ts = ts;
 			pin->work_tx_status = CEC_TX_STATUS_LOW_DRIVE;
+			pin->tx_low_drive_cnt++;
 			wake_up_interruptible(&pin->kthread_waitq);
 			break;
 		}
@@ -656,6 +658,10 @@ static void cec_pin_rx_states(struct cec_pin *pin, ktime_t ts)
 		delta = ktime_us_delta(ts, pin->ts);
 		/* Start bit low is too short, go back to idle */
 		if (delta < CEC_TIM_START_BIT_LOW_MIN - CEC_TIM_IDLE_SAMPLE) {
+			if (!pin->rx_start_bit_low_too_short_cnt++) {
+				pin->rx_start_bit_low_too_short_ts = pin->ts;
+				pin->rx_start_bit_low_too_short_delta = delta;
+			}
 			cec_pin_to_idle(pin);
 			break;
 		}
@@ -676,6 +682,7 @@ static void cec_pin_rx_states(struct cec_pin *pin, ktime_t ts)
 		 * and go to idle. We just pick TOTAL_LONG.
 		 */
 		if (v && delta > CEC_TIM_START_BIT_TOTAL_LONG) {
+			pin->rx_start_bit_too_long_cnt++;
 			cec_pin_to_idle(pin);
 			break;
 		}
@@ -683,6 +690,10 @@ static void cec_pin_rx_states(struct cec_pin *pin, ktime_t ts)
 			break;
 		/* Start bit is too short, go back to idle */
 		if (delta < CEC_TIM_START_BIT_TOTAL_MIN - CEC_TIM_IDLE_SAMPLE) {
+			if (!pin->rx_start_bit_too_short_cnt++) {
+				pin->rx_start_bit_too_short_ts = pin->ts;
+				pin->rx_start_bit_too_short_delta = delta;
+			}
 			cec_pin_to_idle(pin);
 			break;
 		}
@@ -690,6 +701,7 @@ static void cec_pin_rx_states(struct cec_pin *pin, ktime_t ts)
 			/* Error injection: go to low drive */
 			cec_pin_low(pin);
 			pin->state = CEC_ST_RX_LOW_DRIVE;
+			pin->rx_low_drive_cnt++;
 			break;
 		}
 		pin->state = CEC_ST_RX_DATA_SAMPLE;
@@ -728,6 +740,7 @@ static void cec_pin_rx_states(struct cec_pin *pin, ktime_t ts)
 		 * and go to idle. We just pick TOTAL_LONG.
 		 */
 		if (v && delta > CEC_TIM_DATA_BIT_TOTAL_LONG) {
+			pin->rx_data_bit_too_long_cnt++;
 			cec_pin_to_idle(pin);
 			break;
 		}
@@ -738,6 +751,7 @@ static void cec_pin_rx_states(struct cec_pin *pin, ktime_t ts)
 			/* Error injection: go to low drive */
 			cec_pin_low(pin);
 			pin->state = CEC_ST_RX_LOW_DRIVE;
+			pin->rx_low_drive_cnt++;
 			break;
 		}
 
@@ -746,8 +760,13 @@ static void cec_pin_rx_states(struct cec_pin *pin, ktime_t ts)
 		 * too short.
 		 */
 		if (delta < CEC_TIM_DATA_BIT_TOTAL_MIN) {
+			if (!pin->rx_data_bit_too_short_cnt++) {
+				pin->rx_data_bit_too_short_ts = pin->ts;
+				pin->rx_data_bit_too_short_delta = delta;
+			}
 			cec_pin_low(pin);
 			pin->state = CEC_ST_RX_LOW_DRIVE;
+			pin->rx_low_drive_cnt++;
 			break;
 		}
 		pin->ts = ts;
@@ -1148,9 +1167,9 @@ static void cec_pin_adap_status(struct cec_adapter *adap,
 {
 	struct cec_pin *pin = adap->pin;
 
-	seq_printf(file, "state:   %s\n", states[pin->state].name);
-	seq_printf(file, "tx_bit:  %d\n", pin->tx_bit);
-	seq_printf(file, "rx_bit:  %d\n", pin->rx_bit);
+	seq_printf(file, "state: %s\n", states[pin->state].name);
+	seq_printf(file, "tx_bit: %d\n", pin->tx_bit);
+	seq_printf(file, "rx_bit: %d\n", pin->rx_bit);
 	seq_printf(file, "cec pin: %d\n", pin->ops->read(adap));
 	seq_printf(file, "irq failed: %d\n", pin->enable_irq_failed);
 	if (pin->timer_100ms_overruns) {
@@ -1163,11 +1182,44 @@ static void cec_pin_adap_status(struct cec_adapter *adap,
 		seq_printf(file, "avg timer overrun: %u usecs\n",
 			   pin->timer_sum_overrun / pin->timer_100ms_overruns);
 	}
+	if (pin->rx_start_bit_low_too_short_cnt)
+		seq_printf(file,
+			   "rx start bit low too short: %u (delta %u, ts %llu)\n",
+			   pin->rx_start_bit_low_too_short_cnt,
+			   pin->rx_start_bit_low_too_short_delta,
+			   pin->rx_start_bit_low_too_short_ts);
+	if (pin->rx_start_bit_too_short_cnt)
+		seq_printf(file,
+			   "rx start bit too short: %u (delta %u, ts %llu)\n",
+			   pin->rx_start_bit_too_short_cnt,
+			   pin->rx_start_bit_too_short_delta,
+			   pin->rx_start_bit_too_short_ts);
+	if (pin->rx_start_bit_too_long_cnt)
+		seq_printf(file, "rx start bit too long: %u\n",
+			   pin->rx_start_bit_too_long_cnt);
+	if (pin->rx_data_bit_too_short_cnt)
+		seq_printf(file,
+			   "rx data bit too short: %u (delta %u, ts %llu)\n",
+			   pin->rx_data_bit_too_short_cnt,
+			   pin->rx_data_bit_too_short_delta,
+			   pin->rx_data_bit_too_short_ts);
+	if (pin->rx_data_bit_too_long_cnt)
+		seq_printf(file, "rx data bit too long: %u\n",
+			   pin->rx_data_bit_too_long_cnt);
+	seq_printf(file, "rx initiated low drive: %u\n", pin->rx_low_drive_cnt);
+	seq_printf(file, "tx detected low drive: %u\n", pin->tx_low_drive_cnt);
 	pin->timer_cnt = 0;
 	pin->timer_100ms_overruns = 0;
 	pin->timer_300ms_overruns = 0;
 	pin->timer_max_overrun = 0;
 	pin->timer_sum_overrun = 0;
+	pin->rx_start_bit_low_too_short_cnt = 0;
+	pin->rx_start_bit_too_short_cnt = 0;
+	pin->rx_start_bit_too_long_cnt = 0;
+	pin->rx_data_bit_too_short_cnt = 0;
+	pin->rx_data_bit_too_long_cnt = 0;
+	pin->rx_low_drive_cnt = 0;
+	pin->tx_low_drive_cnt = 0;
 	if (pin->ops->status)
 		pin->ops->status(adap, file);
 }