drivers: w1: add vnd,w1 driver for ci testing

This commit adds the vnd,w1 dummy host driver used for ci builds of
1-wire devices.

Signed-off-by: Thomas Stranger <thomas.stranger@outlook.com>

drivers/w1/CMakeLists.txt

@@ -6,7 +6,7 @@ zephyr_sources_ifdef(CONFIG_USERSPACE w1_handlers.c)
 zephyr_library_sources(w1_common.c)
 
 # drivers implementing link functions (read, write, reset)
-# none implemented yet
+zephyr_library_sources_ifdef(CONFIG_W1_TEST           w1_test.c)
 
 # network functions:
 if(CONFIG_W1_NET)

drivers/w1/Kconfig

@@ -22,6 +22,8 @@ config W1_INIT_PRIORITY
 	help
 	  1-Wire device driver initialization priority.
 
+rsource "Kconfig.test"
+
 config W1_NET
 	bool "1-Wire network layer"
 	default y

drivers/w1/Kconfig.test

@@ -0,0 +1,8 @@
+# Copyright (c) 2022, Thomas Stranger
+# SPDX-License-Identifier: Apache-2.0
+
+DT_COMPAT_VND_W1 := vnd,w1
+
+# Hidden option to enable the vnd,w1 1-Wire host driver used in testing.
+config W1_TEST
+	def_bool $(dt_compat_enabled,$(DT_COMPAT_VND_W1))

drivers/w1/w1_test.c

@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2022 Thomas Stranger
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT vnd_w1
+
+/*
+ * This is not a real 1-Wire driver. It is only used to instantiate struct
+ * devices for the "vnd,w1" devicetree compatibe used in test code.
+ */
+#include <zephyr/drivers/w1.h>
+
+struct w1_vnd_config {
+	/** w1 master config, common to all drivers */
+	struct w1_master_config master_config;
+};
+
+struct w1_vnd_data {
+	/** w1 master data, common to all drivers */
+	struct w1_master_data master_data;
+};
+
+static int w1_vnd_reset_bus(const struct device *dev)
+{
+	return -ENOTSUP;
+}
+
+static int w1_vnd_read_bit(const struct device *dev)
+{
+	return -ENOTSUP;
+}
+
+static int w1_vnd_write_bit(const struct device *dev, const bool bit)
+{
+	return -ENOTSUP;
+}
+
+static int w1_vnd_read_byte(const struct device *dev)
+{
+	return -ENOTSUP;
+}
+
+static int w1_vnd_write_byte(const struct device *dev, const uint8_t byte)
+{
+	return -ENOTSUP;
+}
+
+static int w1_vnd_configure(const struct device *dev,
+			    enum w1_settings_type type, uint32_t value)
+{
+	return -ENOTSUP;
+}
+
+static const struct w1_driver_api w1_vnd_api = {
+	.reset_bus = w1_vnd_reset_bus,
+	.read_bit = w1_vnd_read_bit,
+	.write_bit = w1_vnd_write_bit,
+	.read_byte = w1_vnd_read_byte,
+	.write_byte = w1_vnd_write_byte,
+	.configure = w1_vnd_configure,
+};
+
+static int w1_vnd_init(const struct device *dev)
+{
+	return 0;
+}
+
+#define W1_VND_INIT(n)							\
+static const struct w1_vnd_config w1_vnd_cfg_##inst = {			\
+	.master_config.slave_count = W1_INST_SLAVE_COUNT(inst)		\
+};									\
+static struct w1_vnd_data w1_vnd_data_##inst = {};			\
+DEVICE_DT_INST_DEFINE(n, &w1_vnd_init, NULL, &w1_vnd_data_##inst,	\
+		      &w1_vnd_cfg_##inst, POST_KERNEL,			\
+		      CONFIG_W1_INIT_PRIORITY, &w1_vnd_api);
+
+DT_INST_FOREACH_STATUS_OKAY(W1_VND_INIT)

dts/bindings/test/vnd,w1.yaml

@@ -0,0 +1,8 @@
+# Copyright (c) 2022 Thomas Stranger
+# SPDX-License-Identifier: Apache-2.0
+
+description: Test W1 bus master node
+
+compatible: "vnd,w1"
+
+include: [w1-master.yaml]