dts: sensor: adding nodes for STM32 quadrature encoder

Nodes for quadrature encoders are added to the STM32F4 devices

Signed-off-by: Valerio Setti <[email protected]>

Author: valeriosetti

dts/arm/st/f4/stm32f4.dtsi

@@ -1,6 +1,7 @@
 /*
  * Copyright (c) 2017 Linaro Limited
  * Copyright (c) 2019 Centaur Analytics, Inc
+ * Copyright (c) 2022 Valerio Setti <[email protected]>
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -11,6 +12,7 @@
 #include <zephyr/dt-bindings/gpio/gpio.h>
 #include <zephyr/dt-bindings/pwm/pwm.h>
 #include <zephyr/dt-bindings/pwm/stm32_pwm.h>
+#include <zephyr/dt-bindings/sensor/qdec_stm32.h>
 #include <freq.h>
 
 / {
@@ -281,6 +283,12 @@
 				status = "disabled";
 				#pwm-cells = <3>;
 			};
+
+			qdec {
+				compatible = "st,stm32-qdec";
+				status = "disabled";
+				st,input-filter-level = <NO_FILTER>;
+			};
 		};
 
 		timers2: timers@40000000 {
@@ -302,6 +310,12 @@
 				compatible = "st,stm32-counter";
 				status = "disabled";
 			};
+
+			qdec {
+				compatible = "st,stm32-qdec";
+				status = "disabled";
+				st,input-filter-level = <NO_FILTER>;
+			};
 		};
 
 		timers3: timers@40000400 {
@@ -323,6 +337,12 @@
 				compatible = "st,stm32-counter";
 				status = "disabled";
 			};
+
+			qdec {
+				compatible = "st,stm32-qdec";
+				status = "disabled";
+				st,input-filter-level = <NO_FILTER>;
+			};
 		};
 
 		timers4: timers@40000800 {
@@ -344,6 +364,12 @@
 				compatible = "st,stm32-counter";
 				status = "disabled";
 			};
+
+			qdec {
+				compatible = "st,stm32-qdec";
+				status = "disabled";
+				st,input-filter-level = <NO_FILTER>;
+			};
 		};
 
 		timers5: timers@40000c00 {
@@ -365,6 +391,12 @@
 				compatible = "st,stm32-counter";
 				status = "disabled";
 			};
+
+			qdec {
+				compatible = "st,stm32-qdec";
+				status = "disabled";
+				st,input-filter-level = <NO_FILTER>;
+			};
 		};
 
 		timers9: timers@40014000 {

dts/arm/st/f4/stm32f405.dtsi

@@ -109,6 +109,12 @@
 				status = "disabled";
 				#pwm-cells = <3>;
 			};
+
+			qdec {
+				compatible = "st,stm32-qdec";
+				status = "disabled";
+				st,input-filter-level = <NO_FILTER>;
+			};
 		};
 
 		timers12: timers@40001800 {

dts/arm/st/f4/stm32f412.dtsi

@@ -84,6 +84,12 @@
 				status = "disabled";
 				#pwm-cells = <3>;
 			};
+
+			qdec {
+				compatible = "st,stm32-qdec";
+				status = "disabled";
+				st,input-filter-level = <NO_FILTER>;
+			};
 		};
 
 		timers12: timers@40001800 {

dts/bindings/sensor/st,stm32-qdec.yaml

@@ -0,0 +1,74 @@
+# Copyright (c) 2022, Valerio Setti <[email protected]
+# SPDX-License-Identifier: Apache-2.0
+
+description: STM32 quadrature decoder
+
+compatible: "st,stm32-qdec"
+
+include:
+    - name: base.yaml
+    - name: pinctrl-device.yaml
+
+properties:
+     pinctrl-0:
+       required: true
+
+     pinctrl-names:
+       required: true
+
+     st,input-polarity-inverted:
+       type: boolean
+       required: false
+       description: Encoder is triggered by a falling edge on the input pin
+
+     st,input-filter-level:
+       type: int
+       required: false
+       description: |
+         Intensity of the filter applied to the input signal. This is
+         implemented by scaling the sampling frequency and adding a counter
+         in which N consecutive samples with same value are needed to validate
+         a transition.
+         Mapping is as follows (F_clk is the timer's clock):
+         0: No filter, sampling is done at F_dts (default value)
+         1: Fs = F_clk, N=2
+         2: Fs = F_clk, N=4
+         3: Fs = F_clk, N=8
+         4: Fs = F_clk/2, N=6
+         5: Fs = F_clk/2, N=8
+         6: Fs = F_clk/4, N=6
+         7: Fs = F_clk/4, N=8
+         8: Fs = F_clk/8, N=6
+         9: Fs = F_clk/8, N=8
+         10: Fs = F_clk/16, N=5
+         11: Fs = F_clk/16, N=6
+         12: Fs = F_clk/16, N=8
+         13: Fs = F_clk/32, N=5
+         14: Fs = F_clk/32, N=6
+         15: Fs = F_clk/32, N=8
+         Default value is set by hardware at reset
+       default: 0
+       enum:
+         - 0  # No filter
+         - 1  # FDIV1_N2
+         - 2  # FDIV1_N4
+         - 3  # FDIV1_N8
+         - 4  # FDIV2_N6
+         - 5  # FDIV2_N8
+         - 6  # FDIV4_N6
+         - 7  # FDIV4_N8
+         - 8  # FDIV8_N6
+         - 9  # FDIV8_N8
+         - 10 # FDIV16_N5
+         - 11 # FDIV16_N6
+         - 12 # FDIV16_N8
+         - 13 # FDIV32_N5
+         - 14 # FDIV32_N6
+         - 15 # FDIV32_N8
+
+     st,counts-per-revolution:
+       type: int
+       required: true
+       description: |
+         This is a number >= 1 that is used to determine how many revolutions
+         were done based on the current counter's value.

include/zephyr/dt-bindings/sensor/qdec_stm32.h

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2022 Valerio Setti <[email protected]>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#ifndef ZEPHYR_INCLUDE_DT_BINDINGS_QDEC_STM32_H_
+#define ZEPHYR_INCLUDE_DT_BINDINGS_QDEC_STM32_H_
+
+#define NO_FILTER	0
+#define FDIV1_N2	1
+#define FDIV1_N4	2
+#define FDIV1_N8	3
+#define FDIV2_N6	4
+#define FDIV2_N8	5
+#define FDIV4_N6	6
+#define FDIV4_N8	7
+#define FDIV8_N6	8
+#define FDIV8_N8	9
+#define FDIV16_N5	10
+#define FDIV16_N6	11
+#define FDIV16_N8	12
+#define FDIV32_N5	13
+#define FDIV32_N6	14
+#define FDIV32_N8	15
+
+#endif /* ZEPHYR_INCLUDE_DT_BINDINGS_QDEC_STM32_H_ */