ALSA: hda/cirrus_scodec_test: Modernize creation of dummy devices

Replace the old direct use of platform_device APIs with newer KUnit APIs
and the faux bus.

The dummy codec driver device doesn't need to be a platform device.
It can be a faux bus device.

The dummy GPIO driver still must be a platform_device so that a
software_node can be added to it before it probes. But use the new
KUnit-managed APIs to create the platform_device and platform_driver.
These will cleanup automatically when a test completes or fails.

Also use KUnit resource cleanup to destroy the faux bus driver and the GPIO
software node instead of doing this "manually" in test exit() functions.

Signed-off-by: Richard Fitzgerald <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Takashi Iwai <[e-mail]>

sound/pci/hda/cirrus_scodec_test.c

···
 // Copyright (C) 2023 Cirrus Logic, Inc. and
 //                    Cirrus Logic International Semiconductor Ltd.
 
+#include <kunit/platform_device.h>
+#include <kunit/resource.h>
 #include <kunit/test.h>
+#include <linux/device.h>
+#include <linux/device/faux.h>
 #include <linux/gpio/driver.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 
 #include "cirrus_scodec.h"
+
+KUNIT_DEFINE_ACTION_WRAPPER(faux_device_destroy_wrapper, faux_device_destroy,
+			    struct faux_device *)
+KUNIT_DEFINE_ACTION_WRAPPER(device_remove_software_node_wrapper,
+			    device_remove_software_node,
+			    struct device *)
 
 struct cirrus_scodec_test_gpio {
 	unsigned int pin_state;
···
 };
 
 struct cirrus_scodec_test_priv {
-	struct platform_device amp_pdev;
+	struct faux_device *amp_dev;
 	struct platform_device *gpio_pdev;
 	struct cirrus_scodec_test_gpio *gpio_priv;
 };
···
 
 static struct platform_driver cirrus_scodec_test_gpio_driver = {
 	.driver.name	= "cirrus_scodec_test_gpio_drv",
+	.driver.owner	= THIS_MODULE,
 	.probe		= cirrus_scodec_test_gpio_probe,
 };
 
···
 	.name = "cirrus_scodec_test_gpio",
 };
 
-static int cirrus_scodec_test_create_gpio(struct kunit *test)
+static void cirrus_scodec_test_create_gpio(struct kunit *test)
 {
 	struct cirrus_scodec_test_priv *priv = test->priv;
-	int ret;
 
-	priv->gpio_pdev = platform_device_alloc(cirrus_scodec_test_gpio_driver.driver.name, -1);
-	if (!priv->gpio_pdev)
-		return -ENOMEM;
+	KUNIT_ASSERT_EQ(test, 0,
+			kunit_platform_driver_register(test, &cirrus_scodec_test_gpio_driver));
 
-	ret = device_add_software_node(&priv->gpio_pdev->dev, &cirrus_scodec_test_gpio_swnode);
-	if (ret) {
-		platform_device_put(priv->gpio_pdev);
-		KUNIT_FAIL(test, "Failed to add swnode to gpio: %d\n", ret);
-		return ret;
-	}
+	priv->gpio_pdev = kunit_platform_device_alloc(test,
+						      cirrus_scodec_test_gpio_driver.driver.name,
+						      PLATFORM_DEVID_NONE);
+	KUNIT_ASSERT_NOT_NULL(test, priv->gpio_pdev);
 
-	ret = platform_device_add(priv->gpio_pdev);
-	if (ret) {
-		platform_device_put(priv->gpio_pdev);
-		KUNIT_FAIL(test, "Failed to add gpio platform device: %d\n", ret);
-		return ret;
-	}
+	KUNIT_ASSERT_EQ(test, 0, device_add_software_node(&priv->gpio_pdev->dev,
+							  &cirrus_scodec_test_gpio_swnode));
+	KUNIT_ASSERT_EQ(test, 0, kunit_add_action_or_reset(test,
+							   device_remove_software_node_wrapper,
+							   &priv->gpio_pdev->dev));
+
+	KUNIT_ASSERT_EQ(test, 0, kunit_platform_device_add(test, priv->gpio_pdev));
 
 	priv->gpio_priv = dev_get_drvdata(&priv->gpio_pdev->dev);
-	if (!priv->gpio_priv) {
-		platform_device_put(priv->gpio_pdev);
-		KUNIT_FAIL(test, "Failed to get gpio private data\n");
-		return -EINVAL;
-	}
-
-	return 0;
+	KUNIT_ASSERT_NOT_NULL(test, priv->gpio_priv);
 }
 
 static void cirrus_scodec_test_set_gpio_ref_arg(struct software_node_ref_args *arg,
···
 	const struct cirrus_scodec_test_spkid_param *param = test->param_value;
 	int num_spk_id_refs = param->num_amps * param->gpios_per_amp;
 	struct software_node_ref_args *refs;
-	struct device *dev = &priv->amp_pdev.dev;
+	struct device *dev = &priv->amp_dev->dev;
 	unsigned int v;
 	int i, ret;
 
···
 static void cirrus_scodec_test_no_spkid(struct kunit *test)
 {
 	struct cirrus_scodec_test_priv *priv = test->priv;
-	struct device *dev = &priv->amp_pdev.dev;
+	struct device *dev = &priv->amp_dev->dev;
 	int ret;
 
 	ret = cirrus_scodec_get_speaker_id(dev, 0, 4, -1);
 	KUNIT_EXPECT_EQ(test, ret, -ENOENT);
 }
 
-static void cirrus_scodec_test_dev_release(struct device *dev)
-{
-}
-
 static int cirrus_scodec_test_case_init(struct kunit *test)
 {
 	struct cirrus_scodec_test_priv *priv;
-	int ret;
 
 	priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
···
 	test->priv = priv;
 
 	/* Create dummy GPIO */
-	ret = cirrus_scodec_test_create_gpio(test);
-	if (ret < 0)
-		return ret;
+	cirrus_scodec_test_create_gpio(test);
 
 	/* Create dummy amp driver dev */
-	priv->amp_pdev.name = "cirrus_scodec_test_amp_drv";
-	priv->amp_pdev.id = -1;
-	priv->amp_pdev.dev.release = cirrus_scodec_test_dev_release;
-	ret = platform_device_register(&priv->amp_pdev);
-	KUNIT_ASSERT_GE_MSG(test, ret, 0, "Failed to register amp platform device\n");
+	priv->amp_dev = faux_device_create("cirrus_scodec_test_amp_drv", NULL, NULL);
+	KUNIT_ASSERT_NOT_NULL(test, priv->amp_dev);
+	KUNIT_ASSERT_EQ(test, 0, kunit_add_action_or_reset(test,
+							   faux_device_destroy_wrapper,
+							   priv->amp_dev));
 
 	return 0;
-}
-
-static void cirrus_scodec_test_case_exit(struct kunit *test)
-{
-	struct cirrus_scodec_test_priv *priv = test->priv;
-
-	if (priv->amp_pdev.name)
-		platform_device_unregister(&priv->amp_pdev);
-
-	if (priv->gpio_pdev) {
-		device_remove_software_node(&priv->gpio_pdev->dev);
-		platform_device_unregister(priv->gpio_pdev);
-	}
-}
-
-static int cirrus_scodec_test_suite_init(struct kunit_suite *suite)
-{
-	int ret;
-
-	/* Register mock GPIO driver */
-	ret = platform_driver_register(&cirrus_scodec_test_gpio_driver);
-	if (ret < 0) {
-		kunit_err(suite, "Failed to register gpio platform driver, %d\n", ret);
-		return ret;
-	}
-
-	return 0;
-}
-
-static void cirrus_scodec_test_suite_exit(struct kunit_suite *suite)
-{
-	platform_driver_unregister(&cirrus_scodec_test_gpio_driver);
 }
 
 static const struct cirrus_scodec_test_spkid_param cirrus_scodec_test_spkid_param_cases[] = {
···
 
 static struct kunit_suite cirrus_scodec_test_suite = {
 	.name = "snd-hda-scodec-cs35l56-test",
-	.suite_init = cirrus_scodec_test_suite_init,
-	.suite_exit = cirrus_scodec_test_suite_exit,
 	.init = cirrus_scodec_test_case_init,
-	.exit = cirrus_scodec_test_case_exit,
 	.test_cases = cirrus_scodec_test_cases,
 };