linux-kernel - [PATCH v2] counter: microchip-tcb-capture: Handle Signal1 read and Synapse

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Message-Id: <20221018121014.7368-1-william.gray@linaro.org>
Date:   Tue, 18 Oct 2022 08:10:14 -0400
From:   William Breathitt Gray <william.gray@...aro.org>
To:     linux-iio@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        stable@...r.kernel.org,
        William Breathitt Gray <william.gray@...aro.org>,
        Kamel Bouhara <kamel.bouhara@...tlin.com>
Subject: [PATCH v2] counter: microchip-tcb-capture: Handle Signal1 read and Synapse

The signal_read(), action_read(), and action_write() callbacks have been
assuming Signal0 is requested without checking. This results in requests
for Signal1 returning data for Signal0. This patch fixes these
oversights by properly checking for the Signal's id in the respective
callbacks and handling accordingly based on the particular Signal
requested. The trig_inverted member of the mchp_tc_data is removed as
superfluous.

Fixes: 106b104137fd ("counter: Add microchip TCB capture counter")
Cc: stable@...r.kernel.org
Cc: Kamel Bouhara <kamel.bouhara@...tlin.com>
Signed-off-by: William Breathitt Gray <william.gray@...aro.org>
---
Changes in v2:
 - Simplified action_read() changes to just handle qdec_mode and
   non-TIOA Signals before continuing with existing code

 drivers/counter/microchip-tcb-capture.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/counter/microchip-tcb-capture.c b/drivers/counter/microchip-tcb-capture.c
index f9dee15d9777..e2d1dc6ca668 100644
--- a/drivers/counter/microchip-tcb-capture.c
+++ b/drivers/counter/microchip-tcb-capture.c
@@ -28,7 +28,6 @@ struct mchp_tc_data {
 	int qdec_mode;
 	int num_channels;
 	int channel[2];
-	bool trig_inverted;
 };
 
 static const enum counter_function mchp_tc_count_functions[] = {
@@ -153,7 +152,7 @@ static int mchp_tc_count_signal_read(struct counter_device *counter,
 
 	regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], SR), &sr);
 
-	if (priv->trig_inverted)
+	if (signal->id == 1)
 		sigstatus = (sr & ATMEL_TC_MTIOB);
 	else
 		sigstatus = (sr & ATMEL_TC_MTIOA);
@@ -171,6 +170,17 @@ static int mchp_tc_count_action_read(struct counter_device *counter,
 	struct mchp_tc_data *const priv = counter_priv(counter);
 	u32 cmr;
 
+	if (priv->qdec_mode) {
+		*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
+		return 0;
+	}
+
+	/* Only TIOA signal is evaluated in non-QDEC mode */
+	if (synapse->signal->id != 0) {
+		*action = COUNTER_SYNAPSE_ACTION_NONE;
+		return 0;
+	}
+
 	regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], CMR), &cmr);
 
 	switch (cmr & ATMEL_TC_ETRGEDG) {
@@ -199,8 +209,8 @@ static int mchp_tc_count_action_write(struct counter_device *counter,
 	struct mchp_tc_data *const priv = counter_priv(counter);
 	u32 edge = ATMEL_TC_ETRGEDG_NONE;
 
-	/* QDEC mode is rising edge only */
-	if (priv->qdec_mode)
+	/* QDEC mode is rising edge only; only TIOA handled in non-QDEC mode */
+	if (priv->qdec_mode || synapse->signal->id != 0)
 		return -EINVAL;
 
 	switch (action) {
-- 
2.37.3