dts: bindings: add st-morpho-header

All Nucleo boards provide the ST Morpho connector/header, which exposes
all pins of the MCU. It is tipically used in ST shields, so provide a
nexus node to allow creating generic shields.

Signed-off-by: Gerard Marull-Paretas <gerard@teslabs.com>

dts/bindings/gpio/st-morpho-header.yaml

@@ -0,0 +1,13 @@
+# Copyright (c) 2023 Teslabs Engineering S.L.
+# SPDX-License-Identifier: Apache-2.0
+
+description: |
+  GPIO pins exposed on ST Morpho connector.
+
+  The ST morpho connector consists in male pin headers (CN7 and CN10) accessible
+  on both sides of any Nucleo board. They can be used to connect shields. All
+  signals and power pins of the STM32 are available on the ST morpho connector.
+
+compatible: "st-morpho-header"
+
+include: [gpio-nexus.yaml, base.yaml]

include/zephyr/dt-bindings/gpio/st-morpho-header.h

@@ -0,0 +1,94 @@
+/*
+ * Copyright (c) 2023 Teslabs Engineering S.L.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#ifndef INCLUDE_ZEPHYR_DT_BINDINGS_GPIO_ST_MORPHO_HEADER_H_
+#define INCLUDE_ZEPHYR_DT_BINDINGS_GPIO_ST_MORPHO_HEADER_H_
+
+/** ST Morpho pin mask (0...75). */
+#define ST_MORPHO_PIN_MASK 0x7F
+
+/**
+ * @name ST Morpho pin identifiers
+ * @{
+ */
+#define ST_MORPHO_CN7_1	  0
+#define ST_MORPHO_CN7_2	  1
+#define ST_MORPHO_CN7_3	  2
+#define ST_MORPHO_CN7_4	  3
+#define ST_MORPHO_CN7_5	  4
+#define ST_MORPHO_CN7_6	  5
+#define ST_MORPHO_CN7_7	  6
+#define ST_MORPHO_CN7_8	  7
+#define ST_MORPHO_CN7_9	  8
+#define ST_MORPHO_CN7_10  9
+#define ST_MORPHO_CN7_11  10
+#define ST_MORPHO_CN7_12  11
+#define ST_MORPHO_CN7_13  12
+#define ST_MORPHO_CN7_14  13
+#define ST_MORPHO_CN7_15  14
+#define ST_MORPHO_CN7_16  15
+#define ST_MORPHO_CN7_17  16
+#define ST_MORPHO_CN7_18  17
+#define ST_MORPHO_CN7_19  18
+#define ST_MORPHO_CN7_20  19
+#define ST_MORPHO_CN7_21  20
+#define ST_MORPHO_CN7_22  21
+#define ST_MORPHO_CN7_23  22
+#define ST_MORPHO_CN7_24  23
+#define ST_MORPHO_CN7_25  24
+#define ST_MORPHO_CN7_26  25
+#define ST_MORPHO_CN7_27  26
+#define ST_MORPHO_CN7_28  27
+#define ST_MORPHO_CN7_29  28
+#define ST_MORPHO_CN7_30  29
+#define ST_MORPHO_CN7_31  30
+#define ST_MORPHO_CN7_32  31
+#define ST_MORPHO_CN7_33  32
+#define ST_MORPHO_CN7_34  33
+#define ST_MORPHO_CN7_35  34
+#define ST_MORPHO_CN7_36  35
+#define ST_MORPHO_CN7_37  36
+#define ST_MORPHO_CN7_38  37
+#define ST_MORPHO_CN10_1  38
+#define ST_MORPHO_CN10_2  39
+#define ST_MORPHO_CN10_3  40
+#define ST_MORPHO_CN10_4  41
+#define ST_MORPHO_CN10_5  42
+#define ST_MORPHO_CN10_6  43
+#define ST_MORPHO_CN10_7  44
+#define ST_MORPHO_CN10_8  45
+#define ST_MORPHO_CN10_9  46
+#define ST_MORPHO_CN10_10 47
+#define ST_MORPHO_CN10_11 48
+#define ST_MORPHO_CN10_12 49
+#define ST_MORPHO_CN10_13 50
+#define ST_MORPHO_CN10_14 51
+#define ST_MORPHO_CN10_15 52
+#define ST_MORPHO_CN10_16 53
+#define ST_MORPHO_CN10_17 54
+#define ST_MORPHO_CN10_18 55
+#define ST_MORPHO_CN10_19 56
+#define ST_MORPHO_CN10_20 57
+#define ST_MORPHO_CN10_21 58
+#define ST_MORPHO_CN10_22 59
+#define ST_MORPHO_CN10_23 60
+#define ST_MORPHO_CN10_24 61
+#define ST_MORPHO_CN10_25 62
+#define ST_MORPHO_CN10_26 63
+#define ST_MORPHO_CN10_27 64
+#define ST_MORPHO_CN10_28 65
+#define ST_MORPHO_CN10_29 66
+#define ST_MORPHO_CN10_30 67
+#define ST_MORPHO_CN10_31 68
+#define ST_MORPHO_CN10_32 69
+#define ST_MORPHO_CN10_33 70
+#define ST_MORPHO_CN10_34 71
+#define ST_MORPHO_CN10_35 72
+#define ST_MORPHO_CN10_36 73
+#define ST_MORPHO_CN10_37 74
+#define ST_MORPHO_CN10_38 75
+
+/** @} */
+
+#endif /* INCLUDE_ZEPHYR_DT_BINDINGS_GPIO_ST_MORPHO_HEADER_H_ */