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

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>

diff --git a/drivers/counter/microchip-tcb-capture.c b/drivers/counter/microchip-tcb-capture.c
index 2f096a5b973d18edf5de5a2b33f2f72571deefb7..c391ac38b990939c6764a9120a4bd03289f68469 100644 (file)
--- 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_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);