[PATCH 6.12 09/22] counter: microchip-tcb-capture: Fix undefined counter channel state on probe

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: William Breathitt Gray <wbg@kernel.org>

commit c0c9c73434666dc99ee156b25e7e722150bee001 upstream.

Hardware initialize of the timer counter channel does not occur on probe
thus leaving the Count in an undefined state until the first
function_write() callback is executed. Fix this by performing the proper
hardware initialization during probe.

Fixes: 106b104137fd ("counter: Add microchip TCB capture counter")
Reported-by: Csókás Bence <csokas.bence@prolan.hu>
Closes: https://lore.kernel.org/all/bfa70e78-3cc3-4295-820b-3925c26135cb@prolan.hu/
Link: https://lore.kernel.org/r/20250305-preset-capture-mode-microchip-tcb-capture-v1-1-632c95c6421e@kernel.org
Signed-off-by: William Breathitt Gray <wbg@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/counter/microchip-tcb-capture.c |   19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

--- a/drivers/counter/microchip-tcb-capture.c
+++ b/drivers/counter/microchip-tcb-capture.c
@@ -368,6 +368,25 @@ static int mchp_tc_probe(struct platform
 			channel);
 	}
 
+	/* Disable Quadrature Decoder and position measure */
+	ret = regmap_update_bits(regmap, ATMEL_TC_BMR, ATMEL_TC_QDEN | ATMEL_TC_POSEN, 0);
+	if (ret)
+		return ret;
+
+	/* Setup the period capture mode */
+	ret = regmap_update_bits(regmap, ATMEL_TC_REG(priv->channel[0], CMR),
+				 ATMEL_TC_WAVE | ATMEL_TC_ABETRG | ATMEL_TC_CMR_MASK |
+				 ATMEL_TC_TCCLKS,
+				 ATMEL_TC_CMR_MASK);
+	if (ret)
+		return ret;
+
+	/* Enable clock and trigger counter */
+	ret = regmap_write(regmap, ATMEL_TC_REG(priv->channel[0], CCR),
+			   ATMEL_TC_CLKEN | ATMEL_TC_SWTRG);
+	if (ret)
+		return ret;
+
 	priv->tc_cfg = tcb_config;
 	priv->regmap = regmap;
 	counter->name = dev_name(&pdev->dev);