From fd830d0ff53aa70488a69e4eaf3fb0de9205c39f Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Fri, 4 Dec 2020 09:46:22 +0100
Subject: [PATCH] driver core: aux test code

try to test out the aux bus code
---
 drivers/base/Kconfig     |    2 
 drivers/base/Makefile    |    1 
 drivers/base/aux_test.c  |  140 +++++++++++++++++++++++++++++++++++++++++++++++
 drivers/base/auxiliary.c |    1 
 4 files changed, 143 insertions(+), 1 deletion(-)
 create mode 100644 drivers/base/aux_test.c

--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -2,7 +2,7 @@
 menu "Generic Driver Options"
 
 config AUXILIARY_BUS
-	bool
+	tristate "aux bus"
 
 config UEVENT_HELPER
 	bool "Support for uevent helper"
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -8,6 +8,7 @@ obj-y			:= component.o core.o bus.o dd.o
 			   topology.o container.o property.o cacheinfo.o \
 			   swnode.o
 obj-$(CONFIG_AUXILIARY_BUS) += auxiliary.o
+obj-$(CONFIG_AUXILIARY_BUS) += aux_test.o
 obj-$(CONFIG_DEVTMPFS)	+= devtmpfs.o
 obj-y			+= power/
 obj-$(CONFIG_ISA_BUS_API)	+= isa.o
--- /dev/null
+++ b/drivers/base/aux_test.c
@@ -0,0 +1,140 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/auxiliary_bus.h>
+#include <linux/platform_device.h>
+
+
+struct aux_test_device {
+	struct auxiliary_device auxdev;
+	int foo;
+	void *data;
+};
+
+#define aux_dev_to_test_device(auxdev)	\
+	container_of(auxdev, struct aux_test_device, auxdev)
+
+static void aux_test_dev_release(struct device *dev)
+{
+	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
+	struct aux_test_device *test_dev = aux_dev_to_test_device(auxdev);
+
+	kfree(test_dev);
+}
+
+static struct aux_test_device *test_device_alloc(struct device *parent,
+						 const char *name, u32 id)
+{
+	struct aux_test_device *test_dev;
+	struct auxiliary_device *auxdev;
+	int retval;
+
+	test_dev = kzalloc(sizeof(*test_dev), GFP_KERNEL);
+	if (!test_dev)
+		return NULL;
+
+	auxdev= &test_dev->auxdev;
+	auxdev->name = name;
+	auxdev->dev.parent = parent;
+	auxdev->dev.release = aux_test_dev_release;
+	auxdev->id = id;
+
+	retval = auxiliary_device_init(auxdev);
+	if (retval) {
+		dev_err(parent, "aux device failed to init\n");
+		kfree(test_dev);
+		return NULL;
+	}
+
+	return test_dev;
+}
+
+static struct aux_test_device *test_device_create(struct device *parent,
+						  const char *name, u32 id)
+{
+	struct aux_test_device *test_dev;
+	int retval;
+
+	test_dev = test_device_alloc(parent, name, id);
+	if (!test_dev) {
+		dev_err(parent, "aux device %s failed to be created\n", name);
+		return NULL;
+	}
+
+	retval = auxiliary_device_add(&test_dev->auxdev);
+	if (retval) {
+		dev_err(parent, "aux device %s failed to be added, error %d\n",
+			name, retval);
+		auxiliary_device_uninit(&test_dev->auxdev);
+		return NULL;
+	}
+
+	return test_dev;
+}
+
+static void test_dev_del(struct aux_test_device *test_dev)
+{
+	if (!test_dev)
+		return;
+
+	auxiliary_device_delete(&test_dev->auxdev);
+	auxiliary_device_uninit(&test_dev->auxdev);
+}
+
+
+static struct aux_test_device *tdev1, *tdev2, *tdev3;
+
+/* Make a random device to be the "parent" of our tests */
+static struct platform_device *root_device;
+
+static void root_device_release(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	kfree(pdev);
+}
+
+static int __init aux_test_init(void)
+{
+	int retval;
+
+	root_device = kzalloc(sizeof(*root_device), GFP_KERNEL);
+	if (!root_device)
+		return -ENOMEM;
+
+	root_device->name = "aux_test_root";
+	root_device->dev.release = root_device_release;
+
+	retval = platform_device_register(root_device);
+	if (retval) {
+		kfree(root_device);
+		return retval;
+	}
+
+	/* Allocate 3 test devices as a child of this parent */
+	tdev1 = test_device_create(&root_device->dev, "test_dev_1", 21);
+	tdev2 = test_device_create(&root_device->dev, "test_dev_2", 32);
+	tdev3 = test_device_create(&root_device->dev, "test_dev_3", 43);
+
+	return 0;
+}
+
+static void __exit aux_test_exit(void)
+{
+	test_dev_del(tdev1);
+	test_dev_del(tdev2);
+	test_dev_del(tdev3);
+	platform_device_unregister(root_device);
+
+}
+
+
+
+module_init(aux_test_init);
+module_exit(aux_test_exit);
+
+
+MODULE_LICENSE("GPL v2");
--- a/drivers/base/auxiliary.c
+++ b/drivers/base/auxiliary.c
@@ -11,6 +11,7 @@
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/module.h>
+#include <linux/slab.h>
 #include <linux/pm_domain.h>
 #include <linux/pm_runtime.h>
 #include <linux/string.h>