counter: microchip-tcb-capture: Fix undefined counter channel state on probe

commit c0c9c73 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: 106b104 ("counter: Add microchip TCB capture counter")
Reported-by: Csókás Bence <[email protected]>
Closes: https://lore.kernel.org/all/[email protected]/
Link: https://lore.kernel.org/r/20250305-preset-capture-mode-microchip-tcb-capture-v1-1-632c95c6421e@kernel.org
Signed-off-by: William Breathitt Gray <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: William Breathitt Gray

drivers/counter/microchip-tcb-capture.c

@@ -368,6 +368,25 @@ static int mchp_tc_probe(struct platform_device *pdev)
 			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);