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Message-ID: <20241109044151.29804-11-mario.limonciello@amd.com>
Date: Fri, 8 Nov 2024 22:41:39 -0600
From: Mario Limonciello <mario.limonciello@....com>
To: Hans de Goede <hdegoede@...hat.com>, Ilpo Järvinen
	<ilpo.jarvinen@...ux.intel.com>
CC: "Rafael J . Wysocki" <rafael@...nel.org>, Len Brown <lenb@...nel.org>,
	Maximilian Luz <luzmaximilian@...il.com>, Lee Chun-Yi <jlee@...e.com>, "Shyam
 Sundar S K" <Shyam-sundar.S-k@....com>, Corentin Chary
	<corentin.chary@...il.com>, "Luke D . Jones" <luke@...nes.dev>, Ike Panhc
	<ike.pan@...onical.com>, Henrique de Moraes Holschuh <hmh@....eng.br>,
	"Alexis Belmonte" <alexbelm48@...il.com>, Uwe Kleine-König
	<u.kleine-koenig@...gutronix.de>, Ai Chao <aichao@...inos.cn>, Gergo Koteles
	<soyer@....hu>, open list <linux-kernel@...r.kernel.org>, "open list:ACPI"
	<linux-acpi@...r.kernel.org>, "open list:MICROSOFT SURFACE PLATFORM PROFILE
 DRIVER" <platform-driver-x86@...r.kernel.org>, "open list:THINKPAD ACPI
 EXTRAS DRIVER" <ibm-acpi-devel@...ts.sourceforge.net>, Mark Pearson
	<mpearson-lenovo@...ebb.ca>, Matthew Schwartz <matthew.schwartz@...ux.dev>,
	Mario Limonciello <mario.limonciello@....com>
Subject: [PATCH v6 10/22] ACPI: platform_profile: Create class for ACPI platform profile

When registering a platform profile handler create a class device
that will allow changing a single platform profile handler.

The class and sysfs group are no longer needed when the platform profile
core is a module and unloaded, so remove them at that time as well.

Tested-by: Mark Pearson <mpearson-lenovo@...ebb.ca>
Signed-off-by: Mario Limonciello <mario.limonciello@....com>
---
v6:
 * Catch failures in ida_alloc
 * Use 4th argument of device_create instead of dev_set_drvdata()
 * Squash unregister patch
 * Add module init callback
 * Move class creation to module init
 * Update visibility based on group presence
 * Add back parent device
v5:
 * Use ida instead of idr
 * Use device_unregister instead of device_destroy()
 * MKDEV (0, 0)
---
 drivers/acpi/platform_profile.c  | 88 ++++++++++++++++++++++++++++++--
 include/linux/platform_profile.h |  2 +
 2 files changed, 85 insertions(+), 5 deletions(-)

diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c
index 32affb75e782d..ef6af2c655524 100644
--- a/drivers/acpi/platform_profile.c
+++ b/drivers/acpi/platform_profile.c
@@ -5,6 +5,7 @@
 #include <linux/acpi.h>
 #include <linux/bits.h>
 #include <linux/init.h>
+#include <linux/kdev_t.h>
 #include <linux/mutex.h>
 #include <linux/platform_profile.h>
 #include <linux/sysfs.h>
@@ -22,6 +23,12 @@ static const char * const profile_names[] = {
 };
 static_assert(ARRAY_SIZE(profile_names) == PLATFORM_PROFILE_LAST);
 
+static DEFINE_IDA(platform_profile_ida);
+
+static const struct class platform_profile_class = {
+	.name = "platform-profile",
+};
+
 static ssize_t platform_profile_choices_show(struct device *dev,
 					struct device_attribute *attr,
 					char *buf)
@@ -105,8 +112,25 @@ static struct attribute *platform_profile_attrs[] = {
 	NULL
 };
 
+static int profile_class_registered(struct device *dev, const void *data)
+{
+	return 1;
+}
+
+static umode_t profile_class_is_visible(struct kobject *kobj, struct attribute *attr, int idx)
+{
+	if (!class_find_device(&platform_profile_class, NULL, NULL, profile_class_registered))
+		return 0;
+	if (attr == &dev_attr_platform_profile_choices.attr)
+		return 0444;
+	if (attr == &dev_attr_platform_profile.attr)
+		return 0644;
+	return 0;
+}
+
 static const struct attribute_group platform_profile_group = {
-	.attrs = platform_profile_attrs
+	.attrs = platform_profile_attrs,
+	.is_visible = profile_class_is_visible,
 };
 
 void platform_profile_notify(struct platform_profile_handler *pprof)
@@ -123,6 +147,9 @@ int platform_profile_cycle(void)
 	enum platform_profile_option next;
 	int err;
 
+	if (!class_is_registered(&platform_profile_class))
+		return -ENODEV;
+
 	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &profile_lock) {
 		if (!cur_profile)
 			return -ENODEV;
@@ -164,25 +191,76 @@ int platform_profile_register(struct platform_profile_handler *pprof)
 	if (cur_profile)
 		return -EEXIST;
 
-	err = sysfs_create_group(acpi_kobj, &platform_profile_group);
-	if (err)
-		return err;
+	/* create class interface for individual handler */
+	pprof->minor = ida_alloc(&platform_profile_ida, GFP_KERNEL);
+	if (pprof->minor < 0)
+		return pprof->minor;
+	pprof->class_dev = device_create(&platform_profile_class, pprof->dev,
+					 MKDEV(0, 0), pprof, "platform-profile-%d",
+					 pprof->minor);
+	if (IS_ERR(pprof->class_dev)) {
+		err = PTR_ERR(pprof->class_dev);
+		goto cleanup_ida;
+	}
 
 	cur_profile = pprof;
+
+	err = sysfs_update_group(acpi_kobj, &platform_profile_group);
+	if (err)
+		goto cleanup_cur;
+
 	return 0;
+
+cleanup_cur:
+	cur_profile = NULL;
+	device_unregister(pprof->class_dev);
+
+cleanup_ida:
+	ida_free(&platform_profile_ida, pprof->minor);
+
+	return err;
 }
 EXPORT_SYMBOL_GPL(platform_profile_register);
 
 int platform_profile_remove(struct platform_profile_handler *pprof)
 {
+	int id;
 	guard(mutex)(&profile_lock);
 
-	sysfs_remove_group(acpi_kobj, &platform_profile_group);
+	id = pprof->minor;
+	device_unregister(pprof->class_dev);
+	ida_free(&platform_profile_ida, id);
+
 	cur_profile = NULL;
+
+	sysfs_update_group(acpi_kobj, &platform_profile_group);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(platform_profile_remove);
 
+static int __init platform_profile_init(void)
+{
+	int err;
+
+	err = class_register(&platform_profile_class);
+	if (err)
+		return err;
+
+	err = sysfs_create_group(acpi_kobj, &platform_profile_group);
+	if (err)
+		class_unregister(&platform_profile_class);
+
+	return err;
+}
+static void __exit platform_profile_exit(void)
+{
+	class_unregister(&platform_profile_class);
+	sysfs_remove_group(acpi_kobj, &platform_profile_group);
+}
+module_init(platform_profile_init);
+module_exit(platform_profile_exit);
+
 MODULE_AUTHOR("Mark Pearson <markpearson@...ovo.com>");
 MODULE_DESCRIPTION("ACPI platform profile sysfs interface");
 MODULE_LICENSE("GPL");
diff --git a/include/linux/platform_profile.h b/include/linux/platform_profile.h
index 8ec0b8da56db5..a888fd085c513 100644
--- a/include/linux/platform_profile.h
+++ b/include/linux/platform_profile.h
@@ -29,6 +29,8 @@ enum platform_profile_option {
 struct platform_profile_handler {
 	const char *name;
 	struct device *dev;
+	struct device *class_dev;
+	int minor;
 	unsigned long choices[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)];
 	int (*profile_get)(struct platform_profile_handler *pprof,
 				enum platform_profile_option *profile);
-- 
2.43.0


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