Reading and writing the `profile` sysfs file will use the callbacks for
the platform profile handler to read or set the given profile.

Tested-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
v6:
 * Fix return
v5:
 * Drop recovery flow
 * Don't get profile before setting (not needed)
 * Simplify casting for call to _store_class_profile()
 * Only notify legacy interface of changes
 * Adjust mutex use
---
 drivers/acpi/platform_profile.c | 106 ++++++++++++++++++++++++++++++++
 1 file changed, 106 insertions(+)

diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c
index 86d0eb7cc6fc3..c5487d3928c1b 100644
--- a/drivers/acpi/platform_profile.c
+++ b/drivers/acpi/platform_profile.c
@@ -46,6 +46,58 @@ static ssize_t _commmon_choices_show(unsigned long *choices, char *buf)
 	return len;
 }
 
+/**
+ * _store_class_profile - Set the profile for a class device
+ * @dev: The class device
+ * @data: The profile to set
+ */
+static int _store_class_profile(struct device *dev, void *data)
+{
+	struct platform_profile_handler *handler;
+	int *i = (int *)data;
+	int err;
+
+	lockdep_assert_held(&profile_lock);
+	handler = dev_get_drvdata(dev);
+	if (!test_bit(*i, handler->choices))
+		return -EOPNOTSUPP;
+
+	handler = dev_get_drvdata(dev);
+	err = handler->profile_set(handler, *i);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+/**
+ * get_class_profile - Show the current profile for a class device
+ * @dev: The class device
+ * @profile: The profile to return
+ * Return: 0 on success, -errno on failure
+ */
+static int get_class_profile(struct device *dev,
+			     enum platform_profile_option *profile)
+{
+	struct platform_profile_handler *handler;
+	enum platform_profile_option val;
+	int err;
+
+	lockdep_assert_held(&profile_lock);
+	handler = dev_get_drvdata(dev);
+	err = handler->profile_get(handler, &val);
+	if (err) {
+		pr_err("Failed to get profile for handler %s\n", handler->name);
+		return err;
+	}
+
+	if (WARN_ON(val >= PLATFORM_PROFILE_LAST))
+		return -EINVAL;
+	*profile = val;
+
+	return 0;
+}
+
 /**
  * name_show - Show the name of the profile handler
  * @dev: The device
@@ -85,12 +137,66 @@ static ssize_t choices_show(struct device *dev,
 	return -ERESTARTSYS;
 }
 
+/**
+ * profile_show - Show the current profile for a class device
+ * @dev: The device
+ * @attr: The attribute
+ * @buf: The buffer to write to
+ * Return: The number of bytes written
+ */
+static ssize_t profile_show(struct device *dev,
+			    struct device_attribute *attr,
+			    char *buf)
+{
+	enum platform_profile_option profile = PLATFORM_PROFILE_LAST;
+	int err;
+
+	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &profile_lock) {
+		err = get_class_profile(dev, &profile);
+		if (err)
+			return err;
+	}
+
+	return sysfs_emit(buf, "%s\n", profile_names[profile]);
+}
+
+/**
+ * profile_store - Set the profile for a class device
+ * @dev: The device
+ * @attr: The attribute
+ * @buf: The buffer to read from
+ * @count: The number of bytes to read
+ * Return: The number of bytes read
+ */
+static ssize_t profile_store(struct device *dev,
+			     struct device_attribute *attr,
+			     const char *buf, size_t count)
+{
+	int i, ret;
+
+	i = sysfs_match_string(profile_names, buf);
+	if (i < 0)
+		return -EINVAL;
+
+	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &profile_lock) {
+		ret = _store_class_profile(dev, &i);
+		if (ret)
+			return ret;
+	}
+
+	sysfs_notify(acpi_kobj, NULL, "platform_profile");
+
+	return count;
+}
+
 static DEVICE_ATTR_RO(name);
 static DEVICE_ATTR_RO(choices);
+static DEVICE_ATTR_RW(profile);
 
 static struct attribute *profile_attrs[] = {
 	&dev_attr_name.attr,
 	&dev_attr_choices.attr,
+	&dev_attr_profile.attr,
 	NULL
 };
 ATTRIBUTE_GROUPS(profile);
-- 
2.43.0