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

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>

diff --git a/drivers/counter/microchip-tcb-capture.c b/drivers/counter/microchip-tcb-capture.c
index c7af13aca36cfdfd623adb210b4ebd8cdff7a59e..2f631729a870bb22ea0bbb926217682ab957ed3a 100644 (file)
--- a/drivers/counter/microchip-tcb-capture.c
+++ b/drivers/counter/microchip-tcb-capture.c
@@ -369,6 +369,25 @@ 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);