drivers: sensor: mcux qdec add filter parameters

Add optional filter value properties. The filter is disabled by default
but can be enabled by setting the filter-sample-period > 0 in the dts
file. A latency is introduced if the filter is enabled. The latency can
be printed by setting sensor log level to debug.

Signed-off-by: Jeppe Odgaard <jeppe.odgaard@prevas.dk>

drivers/sensor/qdec_mcux/qdec_mcux.c

@@ -166,11 +166,15 @@ static void init_inputs(const struct device *dev)
 		    BUILD_ASSERT(IN_RANGE(DT_INST_PROP(n, p), min, max),	\
 				 STRINGIFY(p) " value is out of range")), ())
 
+#define QDEC_SET_COND(n, v, p)							\
+	COND_CODE_1(DT_INST_NODE_HAS_PROP(n, p), (v = DT_INST_PROP(n, p)), ())
+
 #define QDEC_MCUX_INIT(n)							\
 										\
 	BUILD_ASSERT((DT_PROP_LEN(XBAR_PHANDLE(n), xbar_maps) % 2) == 0,	\
 			"xbar_maps length must be an even number");		\
 	QDEC_CHECK_COND(n, counts_per_revolution, 1, UINT16_MAX);		\
+	QDEC_CHECK_COND(n, filter_sample_period, 0, UINT8_MAX);			\
 										\
 	static struct qdec_mcux_data qdec_mcux_##n##_data = {			\
 		.counts_per_revolution = DT_INST_PROP(n, counts_per_revolution) \
@@ -198,6 +202,12 @@ static void init_inputs(const struct device *dev)
 		ENC_GetDefaultConfig(&data->qdec_config);			\
 		data->qdec_config.decoderWorkMode = int_to_work_mode(		\
 			DT_INST_PROP(n, single_phase_mode));			\
+		QDEC_SET_COND(n, data->qdec_config.filterCount, filter_count);	\
+		QDEC_SET_COND(n, data->qdec_config.filterSamplePeriod,		\
+			  filter_sample_period);				\
+		LOG_DBG("Latency is %u filter clock cycles + 2 IPBus clock "	\
+			"periods", data->qdec_config.filterSamplePeriod *	\
+			(data->qdec_config.filterCount + 3));			\
 		ENC_Init(config->base, &data->qdec_config);			\
 										\
 		/* Update the position counter with initial value. */		\

dts/bindings/sensor/nxp,mcux-qdec.yaml

@@ -28,6 +28,25 @@ properties:
       generates a count signal. The PHASEB input and the REV bit control the
       counter direction.
 
+  filter-count:
+    type: int
+    enum: [0, 1, 2, 3, 4, 5, 6, 7]
+    description: |
+      The number of consecutive samples that must agree prior to the input
+      filter accepting an input transition. A value of 0 represents 3
+      samples. A value of 7 represents 10 samples.
+
+  filter-sample-period:
+    type: int
+    description: |
+      The sampling period (in IPBus clock cycles) of the decoder input signals.
+      Each input is sampled multiple times at the rate specified by the Filter
+      Sample Period. If FILT_PER is 0 (default), then the input filter is
+      bypassed. Bypassing the digital filter enables the position/position
+      difference counters to operate with count rates up to the IPBus
+      frequency. Turning on the input filter introduces a latency of:
+      ((FILT_CNT + 3) * FILT_PER) FILT clock cycles + 2 IPBus clock periods.
+
   xbar:
     type: phandle
     required: true