devicetree: add DT_COMPAT_ON_BUS()

And implement DT_ANY_INST_ON_BUS() in terms of it.

This makes some error messages quite a bit shorter by avoiding
UTIL_LISTIFY(), which has a nasty temper and tends to explode if not
treated gently.

Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>

doc/guides/dts/macros.bnf

@@ -127,6 +127,12 @@ other-macro =  %s"DT_N_" alternate-id
 other-macro =/ %s"DT_N_INST_" dt-name %s"_NUM"
 ; E.g.: #define DT_CHOSEN_zephyr_flash
 other-macro =/ %s"DT_CHOSEN_" dt-name
+; Declares that a compatible has at least one node on a bus.
+;
+; Example:
+;
+;   #define DT_COMPAT_vnd_dev_BUS_spi 1
+other-macro =/ %s"DT_COMPAT_" dt-name %s"_BUS_" dt-name
 
 ; --------------------------------------------------------------------
 ; alternate-id: another way to specify a node besides a path-id

dts/bindings/test/vnd,gpio-expander-i2c.yaml

@@ -0,0 +1,8 @@
+# Copyright (c) 2020 Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+
+description: GPIO expander via I2C
+
+compatible: "vnd,gpio-expander"
+
+include: i2c-device.yaml

dts/bindings/test/vnd,gpio-expander-spi.yaml

@@ -0,0 +1,8 @@
+# Copyright (c) 2020 Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+
+description: GPIO expander via SPI
+
+compatible: "vnd,gpio-expander"
+
+include: spi-device.yaml

include/devicetree.h

@@ -1036,6 +1036,31 @@
  */
 #define DT_ON_BUS(node_id, bus) IS_ENABLED(DT_CAT(node_id, _BUS_##bus))
 
+/**
+ * @brief Test if any node of a compatible is on a bus of a given type
+ *
+ * Example devicetree overlay:
+ *
+ *     &i2c0 {
+ *            temp: temperature-sensor@76 {
+ *                     compatible = "vnd,some-sensor";
+ *                     reg = <0x76>;
+ *            };
+ *     };
+ *
+ * Example usage, assuming "i2c0" is an I2C bus controller node, and
+ * therefore "temp" is on an I2C bus:
+ *
+ *     DT_COMPAT_ON_BUS(vnd_some_sensor, i2c) // 1
+ *
+ * @param compat lowercase-and-underscores version of a compatible
+ * @param bus a binding's bus type as a C token, lowercased and without quotes
+ * @return 1 if any enabled node with that compatible is on that bus type,
+ *         0 otherwise
+ */
+#define DT_COMPAT_ON_BUS(compat, bus) \
+	IS_ENABLED(UTIL_CAT(DT_CAT(DT_COMPAT_, compat), _BUS_##bus))
+
 /**
  * @}
  */
@@ -1319,17 +1344,10 @@
 /**
  * @brief Test if any node with compatible DT_DRV_COMPAT is on a bus
  *
- * This is the same as logically ORing together DT_ON_BUS(node, bus)
+ * This is equivalent to DT_COMPAT_ON_BUS(DT_DRV_COMPAT, bus).
- * for every enabled node which matches compatible DT_DRV_COMPAT.
- *
- * It can be useful, for instance, when writing device drivers for
- * hardware that supports multiple possible bus connections to the
- * SoC.
- *
  * @param bus a binding's bus type as a C token, lowercased and without quotes
  */
-#define DT_ANY_INST_ON_BUS(bus) \
+#define DT_ANY_INST_ON_BUS(bus) DT_COMPAT_ON_BUS(DT_DRV_COMPAT, bus)
-	(UTIL_LISTIFY(DT_NUM_INST(DT_DRV_COMPAT), DT_INST_ON_BUS_OR, bus) 0)
 
 /**
  * @def DT_INST_FOREACH
@@ -1445,8 +1463,6 @@
 #define DT_DASH(...) MACRO_MAP_CAT(DT_DASH_PREFIX, __VA_ARGS__)
 /** @internal helper for DT_DASH(): prepends _ to a name */
 #define DT_DASH_PREFIX(name) _##name
-/** @internal DT_ANY_INST_ON_BUS helper */
-#define DT_INST_ON_BUS_OR(inst, bus) DT_ON_BUS(DT_DRV_INST(inst), bus) ||
 /** @internal DT_INST_FOREACH helper */
 #define DT_CALL_WITH_ARG(arg, expr) expr(arg);
 

scripts/dts/gen_defines.py

@@ -19,6 +19,7 @@
 # edtlib. This will keep this script simple.
 
 import argparse
+from collections import defaultdict
 import os
 import pathlib
 import re
@@ -64,7 +65,7 @@ def main():
             write_vanilla_props(node)
 
         write_chosen(edt)
-        write_inst_num(edt)
+        write_global_compat_info(edt)
 
 
 def parse_args():
@@ -510,26 +511,29 @@ def write_chosen(edt):
         out_define(macro, value, width=max_len)
 
 
-def write_inst_num(edt):
+def write_global_compat_info(edt):
-    # Tree-wide information such as number of instances is printed here.
+    # Tree-wide information related to each compatible, such as number
+    # of instances, is printed here.
 
-    out_comment("Number of instances\n")
+    compat2numinst = {}
-    compat_list = []
+    compat2buses = defaultdict(list)
+    for compat, enabled in edt.compat2enabled.items():
+        compat2numinst[compat] = len(enabled)
 
-    # Walk the nodes to build which compats we need to generate for
+        for node in enabled:
-    for node in sorted(edt.nodes, key=lambda node: node.dep_ordinal):
+            bus = node.on_bus
-        if not node.enabled:
+            if bus is not None and bus not in compat2buses[compat]:
-            continue
+                compat2buses[compat].append(bus)
-        if not node.matching_compat:
-            continue
-        for compat in node.compats:
-            if compat not in compat_list:
-                compat_list.append(compat)
 
-    for compat in compat_list:
+    out_comment("Number of enabled instances of each compatible\n")
-        num_inst = len(edt.compat2enabled[compat])
+    for compat, numinst in compat2numinst.items():
-        out_define(f"DT_N_INST_{str2ident(compat)}_NUM", num_inst)
+        out_define(f"DT_N_INST_{str2ident(compat)}_NUM", numinst)
 
+    out_comment("Bus information for enabled nodes of each compatible\n")
+    for compat, buses in compat2buses.items():
+        for bus in buses:
+            out_define(
+                f"DT_COMPAT_{str2ident(compat)}_BUS_{str2ident(bus)}", 1)
 
 def str2ident(s):
     # Converts 's' to a form suitable for (part of) an identifier

tests/lib/devicetree/app.overlay

@@ -121,6 +121,12 @@
 				label = "TEST_I2C_DEV_10";
 				reg = < 0x10 >;
 			};
+
+			gpio@11 {
+				compatible = "vnd,gpio-expander";
+				reg = <0x11>;
+				label = "TEST_EXPANDER_I2C";
+			};
 		};
 
 		test_spi: spi@33334444 {
@@ -134,7 +140,8 @@
 			clock-frequency = < 2000000 >;
 
 			cs-gpios = <&test_gpio_1 0x10 0x20>,
-					<&test_gpio_2 0x30 0x40>;
+					<&test_gpio_2 0x30 0x40>,
+					<&test_gpio_2 0x50 0x60>;
 
 			/* all vnd,spi-device instances should have CS */
 
@@ -151,6 +158,13 @@
 				reg = <1>;
 				spi-max-frequency = < 2000000 >;
 			};
+
+			gpio@2 {
+				compatible = "vnd,gpio-expander";
+				reg = <2>;
+				label = "TEST_EXPANDER_SPI";
+				spi-max-frequency = <(1 * 1000 * 1000)>;
+			};
 		};
 
 		test_spi_no_cs: spi@55556666 {

tests/lib/devicetree/src/main.c

@@ -292,6 +292,20 @@ static void test_bus(void)
 		     "inst 0 i2c dev label");
 	zassert_true(!strncmp(i2c_bus, DT_INST_BUS_LABEL(0), strlen(i2c_bus)),
 		     "inst 0 i2c bus label");
+
+#undef DT_DRV_COMPAT
+	/*
+	 * Make sure the underlying DT_COMPAT_ON_BUS used by
+	 * DT_ANY_INST_ON_BUS works without DT_DRV_COMPAT defined.
+	 */
+	zassert_equal(DT_COMPAT_ON_BUS(vnd_spi_device, spi), 1, NULL);
+	zassert_equal(DT_COMPAT_ON_BUS(vnd_spi_device, i2c), 0, NULL);
+
+	zassert_equal(DT_COMPAT_ON_BUS(vnd_i2c_device, i2c), 1, NULL);
+	zassert_equal(DT_COMPAT_ON_BUS(vnd_i2c_device, spi), 0, NULL);
+
+	zassert_equal(DT_COMPAT_ON_BUS(vnd_gpio_expander, i2c), 1, NULL);
+	zassert_equal(DT_COMPAT_ON_BUS(vnd_gpio_expander, spi), 1, NULL);
 }
 
 #undef DT_DRV_COMPAT
@@ -1032,7 +1046,7 @@ static void test_cs_gpios(void)
 	zassert_equal(DT_SPI_NUM_CS_GPIOS(TEST_SPI_NO_CS), 0, "wrong no. of cs");
 
 	zassert_equal(DT_SPI_HAS_CS_GPIOS(TEST_SPI), 1, "missing cs");
-	zassert_equal(DT_SPI_NUM_CS_GPIOS(TEST_SPI), 2, "wrong no. of cs");
+	zassert_equal(DT_SPI_NUM_CS_GPIOS(TEST_SPI), 3, "wrong no. of cs");
 
 	zassert_true(!strcmp(DT_SPI_DEV_CS_GPIOS_LABEL(TEST_SPI_DEV_0),
 			     "TEST_GPIO_1"),