Re: [PATCH v5 2/6] platform/x86: firmware_attributes_class: Add high level API for the attributes interface

["Kurt Borja" <kuurtb@gmail.com>]

Hi Alok,

On Sun Jul 6, 2025 at 6:28 AM -03, ALOK TIWARI wrote:
>
>
> On 7/5/2025 9:03 AM, Kurt Borja wrote:
>> Add high level API to aid in the creation of attribute groups attached
>> to the `attrs_kobj` (per ABI specification).
>> 
>> This new API lets users configure each group, either statically or
>> dynamically through a (per type) data struct and then create this group
>> through the generic fwat_create_group() macro.
>> 
>> Signed-off-by: Kurt Borja <kuurtb@gmail.com>
>> ---
>>   drivers/platform/x86/firmware_attributes_class.c | 532 +++++++++++++++++++++++
>>   drivers/platform/x86/firmware_attributes_class.h | 335 ++++++++++++++
>>   2 files changed, 867 insertions(+)
>> 
>> diff --git a/drivers/platform/x86/firmware_attributes_class.c b/drivers/platform/x86/firmware_attributes_class.c
>> index 290364202cce64bb0e9046e0b2bbb8d85e2cbc6f..96473b3b1a2a87cf21a6e2a9a14d72ae322c94ae 100644
>> --- a/drivers/platform/x86/firmware_attributes_class.c
>> +++ b/drivers/platform/x86/firmware_attributes_class.c
>> @@ -10,13 +10,67 @@
>>   #include <linux/module.h>
>>   #include <linux/slab.h>
>>   #include <linux/types.h>
>> +#include <linux/string_choices.h>
>>   #include "firmware_attributes_class.h"
>>   
>> +#define FWAT_TYPE_NONE				-1
>> +
>> +#define to_fwat_bool_data(_c) \
>> +	container_of_const(_c, struct fwat_bool_data, group)
>> +#define to_fwat_enum_data(_c) \
>> +	container_of_const(_c, struct fwat_enum_data, group)
>> +#define to_fwat_int_data(_c) \
>> +	container_of_const(_c, struct fwat_int_data, group)
>> +#define to_fwat_str_data(_c) \
>> +	container_of_const(_c, struct fwat_str_data, group)
>> +
>> +struct fwat_attribute {
>> +	struct attribute attr;
>> +	ssize_t (*show)(struct kobject *kobj, struct fwat_attribute *attr,
>> +			char *buf);
>> +	ssize_t (*store)(struct kobject *kobj, struct fwat_attribute *attr,
>> +			 const char *buf, size_t count);
>> +	int type;
>> +};
>> +
>> +#define to_fwat_attribute(_a) \
>> +	container_of_const(_a, struct fwat_attribute, attr)
>> +
>> +#define __FWAT_ATTR(_name, _mode, _show, _store, _type) \
>> +	{								\
>> +		.attr = { .name = __stringify(_name), .mode = _mode },	\
>> +		.show = _show, .store = _store, .type = _type,		\
>> +	}
>> +
>> +#define FWAT_ATTR_RO(_prefix, _name, _show, _type) \
>> +	static struct fwat_attribute fwat_##_prefix##_##_name##_attr = \
>> +		__FWAT_ATTR(_name, 0444, _show, NULL, _type)
>> +
>> +#define FWAT_ATTR_RW(_prefix, _name, _show, _store, _type) \
>> +	static struct fwat_attribute fwat_##_prefix##_##_name##_attr = \
>> +		__FWAT_ATTR(_name, 0644, _show, _store, _type)
>> +
>> +struct fwat_group {
>> +	const struct fwat_group_data *data;
>> +	struct device *dev;
>> +	struct kobject kobj;
>> +};
>> +
>> +#define kobj_to_fwat_group(_k) \
>> +	container_of_const(_k, struct fwat_group, kobj)
>> +
>>   const struct class firmware_attributes_class = {
>>   	.name = "firmware-attributes",
>>   };
>>   EXPORT_SYMBOL_GPL(firmware_attributes_class);
>>   
>> +static const char * const fwat_type_labels[] = {
>> +	[fwat_group_boolean]			= "boolean",
>> +	[fwat_group_enumeration]		= "enumeration",
>> +	[fwat_group_integer]			= "integer",
>> +	[fwat_group_string]			= "string",
>> +};
>> +
>>   static void fwat_device_release(struct device *dev)
>>   {
>>   	struct fwat_device *fadev = to_fwat_device(dev);
>> @@ -24,6 +78,483 @@ static void fwat_device_release(struct device *dev)
>>   	kfree(fadev);
>>   }
>>   
>> +static ssize_t
>> +type_show(struct kobject *kobj, struct fwat_attribute *attr, char *buf)
>> +{
>> +	return sysfs_emit(buf, "%s\n", fwat_type_labels[attr->type]);
>> +}
>> +
>> +static ssize_t
>> +display_name_show(struct kobject *kobj, struct fwat_attribute *attr, char *buf)
>> +{
>> +	struct fwat_group *group = kobj_to_fwat_group(kobj);
>> +	const char *disp_name = group->data->display_name;
>> +
>> +	if (!disp_name)
>> +		return -EOPNOTSUPP;
>> +
>> +	return sysfs_emit(buf, "%s\n", disp_name);
>> +}
>> +
>> +static ssize_t
>> +display_name_language_code_show(struct kobject *kobj, struct fwat_attribute *attr,
>> +				char *buf)
>> +{
>> +	struct fwat_group *group = kobj_to_fwat_group(kobj);
>> +	const char *lang_code = group->data->language_code;
>> +
>> +	if (!lang_code)
>> +		return -EOPNOTSUPP;
>> +
>> +	return sysfs_emit(buf, "%s\n", lang_code);
>> +}
>> +
>> +static ssize_t
>> +bool_group_show(struct kobject *kobj, struct fwat_attribute *attr, char *buf)
>> +{
>> +	const struct fwat_group *group = kobj_to_fwat_group(kobj);
>> +	const struct fwat_bool_data *data = to_fwat_bool_data(group->data);
>> +	bool val;
>> +	int ret;
>> +
>> +	/* show_override does not affect current_value */
>> +	if (data->group.show_override && attr->type != fwat_bool_current_value)
>> +		return data->group.show_override(group->dev, attr->type, buf);
>> +
>> +	switch (attr->type) {
>> +	case fwat_bool_current_value:
>> +		ret = data->read(group->dev, data->group.id, &val);
>> +		if (ret < 0)
>> +			return ret;
>> +		break;
>> +	case fwat_bool_default_value:
>> +		val = data->default_val;
>> +		break;
>> +	default:
>> +		return -EOPNOTSUPP;
>> +	}
>> +
>> +	return sysfs_emit(buf, "%s\n", str_yes_no(val));
>> +}
>> +
>> +static ssize_t
>> +bool_group_store(struct kobject *kobj, struct fwat_attribute *attr, const char *buf,
>> +		 size_t count)
>> +{
>> +	const struct fwat_group *group = kobj_to_fwat_group(kobj);
>> +	const struct fwat_bool_data *data = to_fwat_bool_data(group->data);
>> +	bool val;
>> +	int ret;
>> +
>> +	ret = kstrtobool(buf, &val);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = data->write(group->dev, data->group.id, val);
>> +	if (ret)
>> +		return ret;
>> +
>> +	return count;
>> +}
>> +
>> +static ssize_t
>> +enum_group_show(struct kobject *kobj, struct fwat_attribute *attr, char *buf)
>> +{
>> +	const struct fwat_group *group = kobj_to_fwat_group(kobj);
>> +	const struct fwat_enum_data *data = to_fwat_enum_data(group->data);
>> +	int val_idx, sz = 0;
>> +	int ret;
>> +
>> +	/* show_override does not affect current_value */
>> +	if (data->group.show_override && attr->type != fwat_enum_current_value)
>> +		return data->group.show_override(group->dev, attr->type, buf);
>> +
>> +	switch (attr->type) {
>> +	case fwat_enum_current_value:
>> +		ret = data->read(group->dev, data->group.id, &val_idx);
>> +		if (ret < 0)
>> +			return ret;
>> +		break;
>> +	case fwat_enum_default_value:
>> +		val_idx = data->default_idx;
>> +		break;
>> +	case fwat_enum_possible_values:
>> +		sz += sysfs_emit_at(buf, sz, "%s", data->possible_vals[0]);
>> +		for (unsigned int i = 1; data->possible_vals[i]; i++)
>> +			sz += sysfs_emit_at(buf, sz, ";%s", data->possible_vals[i]);
>> +		sz += sysfs_emit_at(buf, sz, "\n");
>> +		return sz;
>> +	default:
>> +		return -EOPNOTSUPP;
>> +	}
>> +
>> +	return sysfs_emit(buf, "%s\n", data->possible_vals[val_idx]);
>> +}
>> +
>> +static ssize_t
>> +enum_group_store(struct kobject *kobj, struct fwat_attribute *attr, const char *buf,
>> +		 size_t count)
>> +{
>> +	const struct fwat_group *group = kobj_to_fwat_group(kobj);
>> +	const struct fwat_enum_data *data = to_fwat_enum_data(group->data);
>> +	int val_idx;
>> +	int ret;
>> +
>> +	val_idx = __sysfs_match_string(data->possible_vals, -1, buf);
>> +	if (val_idx < 0)
>> +		return val_idx;
>> +
>> +	ret = data->write(group->dev, data->group.id, val_idx);
>> +	if (ret)
>> +		return ret;
>> +
>> +	return count;
>> +}
>> +
>> +static ssize_t
>> +int_group_show(struct kobject *kobj, struct fwat_attribute *attr, char *buf)
>> +{
>> +	const struct fwat_group *group = kobj_to_fwat_group(kobj);
>> +	const struct fwat_int_data *data = to_fwat_int_data(group->data);
>> +	long val;
>> +	int ret;
>> +
>> +	/* show_override does not affect current_value */
>> +	if (data->group.show_override && attr->type != fwat_int_current_value)
>> +		return data->group.show_override(group->dev, attr->type, buf);
>> +
>> +	switch (attr->type) {
>> +	case fwat_int_current_value:
>> +		ret = data->read(group->dev, data->group.id, &val);
>> +		if (ret < 0)
>> +			return ret;
>> +		break;
>> +	case fwat_int_default_value:
>> +		val = data->default_val;
>> +		break;
>> +	case fwat_int_min_value:
>> +		val = data->min_val;
>> +		break;
>> +	case fwat_int_max_value:
>> +		val = data->max_val;
>> +		break;
>> +	case fwat_int_scalar_increment:
>> +		val = data->increment;
>> +		break;
>> +	default:
>> +		return -EOPNOTSUPP;
>> +	}
>> +
>> +	return sysfs_emit(buf, "%ld\n", val);
>> +}
>> +
>> +static ssize_t
>> +int_group_store(struct kobject *kobj, struct fwat_attribute *attr, const char *buf,
>> +		size_t count)
>> +{
>> +	const struct fwat_group *group = kobj_to_fwat_group(kobj);
>> +	const struct fwat_int_data *data = to_fwat_int_data(group->data);
>> +	long val;
>> +	int ret;
>> +
>> +	ret = kstrtol(buf, 0, &val);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = data->write(group->dev, data->group.id, val);
>> +	if (ret)
>> +		return ret;
>> +
>> +	return count;
>> +}
>> +
>> +static ssize_t
>> +str_group_show(struct kobject *kobj, struct fwat_attribute *attr, char *buf)
>> +{
>> +	const struct fwat_group *group = kobj_to_fwat_group(kobj);
>> +	const struct fwat_str_data *data = to_fwat_str_data(group->data);
>> +	const char *val;
>> +	long len;
>> +	int ret;
>> +
>> +	/* show_override does not affect current_value */
>> +	if (data->group.show_override && attr->type != fwat_bool_current_value)
>
> fwat_bool_current_value ? or str
>
>> +		return data->group.show_override(group->dev, attr->type, buf);
>> +
>> +	switch (attr->type) {
>> +	case fwat_str_current_value:
>> +		ret = data->read(group->dev, data->group.id, &val);
>> +		if (ret < 0)
>> +			return ret;
>> +		break;
>> +	case fwat_str_default_value:
>> +		val = data->default_val;
>> +		break;
>> +	case fwat_str_min_length:
>> +		len = data->min_len;
>> +		return sysfs_emit(buf, "%ld\n", len);
>> +	case fwat_str_max_length:
>> +		len = data->max_len;
>> +		return sysfs_emit(buf, "%ld\n", len);
>> +	default:
>> +		return -EOPNOTSUPP;
>> +	}
>> +
>> +	return sysfs_emit(buf, "%s\n", val);
>> +}
>> +
>> +static ssize_t
>> +str_group_store(struct kobject *kobj, struct fwat_attribute *attr, const char *buf,
>> +		size_t count)
>> +{
>> +	const struct fwat_group *group = kobj_to_fwat_group(kobj);
>> +	const struct fwat_str_data *data = to_fwat_str_data(group->data);
>> +	int ret;
>> +
>> +	ret = data->write(group->dev, data->group.id, buf);
>> +	if (ret)
>> +		return ret;
>> +
>> +	return count;
>> +}
>> +
>> +FWAT_ATTR_RO(all, display_name, display_name_show, FWAT_TYPE_NONE);
>> +FWAT_ATTR_RO(all, display_name_language_code, display_name_language_code_show, FWAT_TYPE_NONE);
>> +
>> +FWAT_ATTR_RO(bool, type, type_show, fwat_group_boolean);
>> +FWAT_ATTR_RW(bool, current_value, bool_group_show, bool_group_store, fwat_bool_current_value);
>> +FWAT_ATTR_RO(bool, default_value, bool_group_show, fwat_bool_default_value);
>> +
>> +FWAT_ATTR_RO(enum, type, type_show, fwat_group_enumeration);
>> +FWAT_ATTR_RW(enum, current_value, enum_group_show, enum_group_store, fwat_enum_current_value);
>> +FWAT_ATTR_RO(enum, default_value, enum_group_show, fwat_enum_default_value);
>> +FWAT_ATTR_RO(enum, possible_values, enum_group_show, fwat_enum_possible_values);
>> +
>> +FWAT_ATTR_RO(int, type, type_show, fwat_group_integer);
>> +FWAT_ATTR_RW(int, current_value, int_group_show, int_group_store, fwat_int_current_value);
>> +FWAT_ATTR_RO(int, default_value, int_group_show, fwat_int_default_value);
>> +FWAT_ATTR_RO(int, min_value, int_group_show, fwat_int_min_value);
>> +FWAT_ATTR_RO(int, max_value, int_group_show, fwat_int_max_value);
>> +FWAT_ATTR_RO(int, scalar_increment, int_group_show, fwat_int_scalar_increment);
>> +
>> +FWAT_ATTR_RO(str, type, type_show, fwat_group_string);
>> +FWAT_ATTR_RW(str, current_value, str_group_show, str_group_store, fwat_int_current_value);
>
> wrong enum fwat_int_current_value -> fwat_str_current_value
>
>> +FWAT_ATTR_RO(str, default_value, str_group_show, fwat_str_default_value);
>> +FWAT_ATTR_RO(str, min_length, str_group_show, fwat_str_min_length);
>> +FWAT_ATTR_RO(str, max_length, str_group_show, fwat_str_max_length);
>> +
>> +static struct attribute *fwat_bool_attrs[] = {
>> +	&fwat_bool_type_attr.attr,
>> +	&fwat_all_display_name_attr.attr,
>> +	&fwat_all_display_name_language_code_attr.attr,
>> +	&fwat_bool_current_value_attr.attr,
>> +	&fwat_bool_default_value_attr.attr,
>> +	NULL
>> +};
>> +
>> +static struct attribute *fwat_enum_attrs[] = {
>> +	&fwat_enum_type_attr.attr,
>> +	&fwat_all_display_name_attr.attr,
>> +	&fwat_all_display_name_language_code_attr.attr,
>> +	&fwat_enum_current_value_attr.attr,
>> +	&fwat_enum_default_value_attr.attr,
>> +	&fwat_enum_possible_values_attr.attr,
>> +	NULL
>> +};
>> +
>> +static struct attribute *fwat_int_attrs[] = {
>> +	&fwat_int_type_attr.attr,
>> +	&fwat_all_display_name_attr.attr,
>> +	&fwat_all_display_name_language_code_attr.attr,
>> +	&fwat_int_current_value_attr.attr,
>> +	&fwat_int_default_value_attr.attr,
>> +	&fwat_int_min_value_attr.attr,
>> +	&fwat_int_max_value_attr.attr,
>> +	&fwat_int_scalar_increment_attr.attr,
>> +	NULL
>> +};
>> +
>> +static struct attribute *fwat_str_attrs[] = {
>> +	&fwat_str_type_attr.attr,
>> +	&fwat_all_display_name_attr.attr,
>> +	&fwat_all_display_name_language_code_attr.attr,
>> +	&fwat_str_current_value_attr.attr,
>> +	&fwat_str_default_value_attr.attr,
>> +	&fwat_str_min_length_attr.attr,
>> +	&fwat_str_max_length_attr.attr,
>> +	NULL
>> +};
>> +
>> +static umode_t fwat_attr_visible(struct kobject *kobj, struct attribute *attr, int n)
>> +{
>> +	struct fwat_attribute *fwat_attr = to_fwat_attribute(attr);
>> +	struct fwat_group *group = kobj_to_fwat_group(kobj);
>> +	const struct fwat_group_data *data = group->data;
>> +
>> +	/* The `type` attribute is always first */
>> +	if (n == 0)
>> +		return attr->mode;
>> +
>> +	if (attr == &fwat_all_display_name_attr.attr)
>> +		return data->display_name ? attr->mode : 0;
>> +
>> +	if (attr == &fwat_all_display_name_language_code_attr.attr)
>> +		return data->language_code ? attr->mode : 0;
>> +
>> +	/* The `current_value` attribute always has type == 0 */
>> +	if (!fwat_attr->type)
>> +		return data->mode;
>> +
>> +	return test_bit(fwat_attr->type, &data->fattrs) ? attr->mode : 0;
>> +}
>> +
>> +static umode_t fwat_group_visible(struct kobject *kobj)
>> +{
>> +	return true;
>> +}
>> +
>> +DEFINE_SYSFS_GROUP_VISIBLE(fwat);
>> +
>> +static const struct attribute_group fwat_bool_group = {
>> +	.attrs = fwat_bool_attrs,
>> +	.is_visible = SYSFS_GROUP_VISIBLE(fwat),
>> +};
>> +__ATTRIBUTE_GROUPS(fwat_bool);
>> +
>> +static const struct attribute_group fwat_enum_group = {
>> +	.attrs = fwat_enum_attrs,
>> +	.is_visible = SYSFS_GROUP_VISIBLE(fwat),
>> +};
>> +__ATTRIBUTE_GROUPS(fwat_enum);
>> +
>> +static const struct attribute_group fwat_int_group = {
>> +	.attrs = fwat_int_attrs,
>> +	.is_visible = SYSFS_GROUP_VISIBLE(fwat),
>> +};
>> +__ATTRIBUTE_GROUPS(fwat_int);
>> +
>> +static const struct attribute_group fwat_str_group = {
>> +	.attrs = fwat_str_attrs,
>> +	.is_visible = SYSFS_GROUP_VISIBLE(fwat),
>> +};
>> +__ATTRIBUTE_GROUPS(fwat_str);
>> +
>> +static ssize_t
>> +fwat_attr_sysfs_show(struct kobject *kobj, struct attribute *attr, char *buf)
>> +{
>> +	struct fwat_attribute *fwat_attr = to_fwat_attribute(attr);
>> +
>> +	if (!fwat_attr->show)
>> +		return -EOPNOTSUPP;
>> +
>> +	return fwat_attr->show(kobj, fwat_attr, buf);
>> +}
>> +
>> +static ssize_t
>> +fwat_attr_sysfs_store(struct kobject *kobj, struct attribute *attr, const char *buf,
>> +		      size_t count)
>> +{
>> +	struct fwat_attribute *fwat_attr = to_fwat_attribute(attr);
>> +
>> +	if (!fwat_attr->show)
>> +		return -EOPNOTSUPP;
>
> check for fwat_attr->store ?
>
>> +
>> +	return fwat_attr->store(kobj, fwat_attr, buf, count);
>> +}
>> +
>> +static void fwat_group_release(struct kobject *kobj)
>> +{
>> +	struct fwat_group *group = kobj_to_fwat_group(kobj);
>> +
>> +	kfree(group);
>> +}
>> +
>> +static const struct sysfs_ops fwat_attr_sysfs_ops = {
>> +	.show = fwat_attr_sysfs_show,
>> +	.store = fwat_attr_sysfs_store,
>> +};
>> +
>> +static const struct kobj_type fwat_boolean_ktype = {
>> +	.sysfs_ops = &fwat_attr_sysfs_ops,
>> +	.release = fwat_group_release,
>> +	.default_groups = fwat_bool_groups,
>> +};
>> +
>> +static const struct kobj_type fwat_enumeration_ktype = {
>> +	.sysfs_ops = &fwat_attr_sysfs_ops,
>> +	.release = fwat_group_release,
>> +	.default_groups = fwat_enum_groups,
>> +};
>> +
>> +static const struct kobj_type fwat_integer_ktype = {
>> +	.sysfs_ops = &fwat_attr_sysfs_ops,
>> +	.release = fwat_group_release,
>> +	.default_groups = fwat_int_groups,
>> +};
>> +
>> +static const struct kobj_type fwat_string_ktype = {
>> +	.sysfs_ops = &fwat_attr_sysfs_ops,
>> +	.release = fwat_group_release,
>> +	.default_groups = fwat_str_groups,
>> +};
>> +
>> +static int __fwat_create_group(struct fwat_device *fadev, const struct kobj_type *ktype,
>> +			       const struct fwat_group_data *data)
>> +{
>> +	struct fwat_group *group;
>> +	int ret;
>> +
>> +	group = kzalloc(sizeof(*group), GFP_KERNEL);
>> +	if (!group)
>> +		return -ENOMEM;
>> +
>> +	group->dev = &fadev->dev;
>> +	group->data = data;
>> +
>> +	group->kobj.kset = fadev->attrs_kset;
>> +	ret = kobject_init_and_add(&group->kobj, ktype, NULL, "%s", data->name);
>> +	if (ret) {
>> +		kobject_put(&group->kobj);
>> +		return ret;
>> +	}
>> +
>> +	kobject_uevent(&group->kobj, KOBJ_ADD);
>> +
>> +	return 0;
>> +}
>> +
>> +static void fwat_remove_auto_groups(struct fwat_device *fadev)
>> +{
>> +	struct kobject *pos, *n;
>> +
>> +	list_for_each_entry_safe(pos, n, &fadev->attrs_kset->list, entry)
>> +		kobject_put(pos);
>> +}
>> +
>> +int fwat_create_bool_group(struct fwat_device *fadev, const struct fwat_bool_data *data)
>> +{
>> +	return __fwat_create_group(fadev, &fwat_boolean_ktype, &data->group);
>> +}
>> +EXPORT_SYMBOL_GPL(fwat_create_bool_group);
>> +
>> +int fwat_create_enum_group(struct fwat_device *fadev, const struct fwat_enum_data *data)
>> +{
>> +	return __fwat_create_group(fadev, &fwat_enumeration_ktype, &data->group);
>> +}
>> +EXPORT_SYMBOL_GPL(fwat_create_enum_group);
>> +
>> +int fwat_create_int_group(struct fwat_device *fadev, const struct fwat_int_data *data)
>> +{
>> +	return __fwat_create_group(fadev, &fwat_integer_ktype, &data->group);
>> +}
>> +EXPORT_SYMBOL_GPL(fwat_create_int_group);
>> +
>> +int fwat_create_str_group(struct fwat_device *fadev, const struct fwat_str_data *data)
>> +{
>> +	return __fwat_create_group(fadev, &fwat_string_ktype, &data->group);
>> +}
>> +EXPORT_SYMBOL_GPL(fwat_create_str_group);
>> +
>>   /**
>>    * fwat_device_register - Create and register a firmware-attributes class
>>    *			  device
>> @@ -89,6 +620,7 @@ void fwat_device_unregister(struct fwat_device *fadev)
>>   	if (!fadev)
>>   		return;
>>   
>> +	fwat_remove_auto_groups(fadev);
>>   	sysfs_remove_groups(&fadev->attrs_kset->kobj, fadev->groups);
>>   	kset_unregister(fadev->attrs_kset);
>>   	device_unregister(&fadev->dev);
>> diff --git a/drivers/platform/x86/firmware_attributes_class.h b/drivers/platform/x86/firmware_attributes_class.h
>> index 048fd0904f767357ef856e687ec4cf3260016ec6..e8868ce05b595eda94a98975428391b9f9341e3d 100644
>> --- a/drivers/platform/x86/firmware_attributes_class.h
>> +++ b/drivers/platform/x86/firmware_attributes_class.h
>> @@ -10,6 +10,7 @@
>>   #include <linux/device/class.h>
>>   #include <linux/kobject.h>
>>   #include <linux/sysfs.h>
>> +#include <linux/list.h>
>>   
>>   extern const struct class firmware_attributes_class;
>>   
>> @@ -27,6 +28,340 @@ struct fwat_device {
>>   
>>   #define to_fwat_device(_d)	container_of_const(_d, struct fwat_device, dev)
>>   
>> +enum fwat_group_type {
>> +	fwat_group_boolean,
>> +	fwat_group_enumeration,
>> +	fwat_group_integer,
>> +	fwat_group_string,
>> +};
>> +
>> +enum fwat_bool_attrs {
>> +	fwat_bool_current_value,
>> +	fwat_bool_default_value,
>> +	fwat_bool_attrs_last
>> +};
>> +
>> +#define FWAT_BOOL_CURRENT_VALUE			BIT(fwat_bool_current_value)
>> +#define FWAT_BOOL_DEFAULT_VALUE			BIT(fwat_bool_default_value)
>> +#define FWAT_BOOL_ALL_ATTRS			GENMASK(fwat_bool_attrs_last, 0)
>> +
>> +enum fwat_enum_attrs {
>> +	fwat_enum_current_value,
>> +	fwat_enum_default_value,
>> +	fwat_enum_possible_values,
>> +	fwat_enum_attrs_last
>> +};
>> +
>> +#define FWAT_ENUM_CURRENT_VALUE			BIT(fwat_enum_current_value)
>> +#define FWAT_ENUM_DEFAULT_VALUE			BIT(fwat_enum_default_value)
>> +#define FWAT_ENUM_POSSIBLE_VALUES		BIT(fwat_enum_possible_values)
>> +#define FWAT_ENUM_ALL_ATTRS			GENMASK(fwat_enum_attrs_last, 0)
>> +
>> +enum fwat_int_attrs {
>> +	fwat_int_current_value,
>> +	fwat_int_default_value,
>> +	fwat_int_min_value,
>> +	fwat_int_max_value,
>> +	fwat_int_scalar_increment,
>> +	fwat_int_attrs_last
>> +};
>> +
>> +#define FWAT_INT_CURRENT_VALUE			BIT(fwat_int_current_value)
>> +#define FWAT_INT_DEFAULT_VALUE			BIT(fwat_int_default_value)
>> +#define FWAT_INT_MIN_VALUE			BIT(fwat_int_min_value)
>> +#define FWAT_INT_MAX_VALUE			BIT(fwat_int_max_value)
>> +#define FWAT_INT_SCALAR_INCREMENT		BIT(fwat_int_scalar_increment)
>> +#define FWAT_INT_ALL_ATTRS			GENMASK(fwat_int_attrs_last, 0)
>> +
>> +enum fwat_str_attrs {
>> +	fwat_str_current_value,
>> +	fwat_str_default_value,
>> +	fwat_str_min_length,
>> +	fwat_str_max_length,
>> +	fwat_str_attrs_last
>> +};
>> +
>> +#define FWAT_STR_CURRENT_VALUE			BIT(fwat_str_current_value)
>> +#define FWAT_STR_DEFAULT_VALUE			BIT(fwat_str_default_value)
>> +#define FWAT_STR_MIN_LENGTH			BIT(fwat_str_min_length)
>> +#define FWAT_STR_MAX_LENGTH			BIT(fwat_str_max_length)
>> +#define FWAT_STR_ALL_ATTRS			GENMASK(fwat_str_attrs_last, 0)
>> +
>> +static_assert(fwat_bool_current_value == 0);
>> +static_assert(fwat_enum_current_value == 0);
>> +static_assert(fwat_int_current_value == 0);
>> +static_assert(fwat_str_current_value == 0);
>> +
>> +/**
>> + * struct fwat_group_data - Data struct common between group types
>> + * @id: Group ID defined by the user.
>> + * @name: Name of the group.
>> + * @display_name: Name showed in the display_name attribute. (Optional)
>> + * @language_code: Language code showed in the display_name_language_code
>> + *                 attribute. (Optional)
>> + * @mode: Mode for the current_value attribute. All other attributes will have
>> + *        0444 permissions.
>> + * @fattrs: Bitmap of selected attributes for this group type.
>> + * @show_override: Custom show method for attributes in this group, except for
>> + *		   the current_value attribute, for which the a `read` callback
>> + *		   will still be used. (Optional)
>> + *
>> + * NOTE: This struct is not meant to be defined directly. It is supposed to be
>> + * embedded and defined as part of fwat_[type]_data structs.
>> + */
>> +struct fwat_group_data {
>> +	long id;
>> +	umode_t mode;
>> +	const char *name;
>> +	const char *display_name;
>> +	const char *language_code;
>> +	unsigned long fattrs;
>> +	ssize_t (*show_override)(struct device *dev, int type, char *buf);
>> +};
>> +
>> +/**
>> + * struct fwat_bool_data - Data struct for the boolean group type
>> + * @read: Read callback for the current_value attribute.
>> + * @write: Write callback for the current_value attribute.
>> + * @default_val: Default value.
>> + * @group: Group data.
>> + */
>> +struct fwat_bool_data {
>> +	int (*read)(struct device *dev, long id, bool *val);
>> +	int (*write)(struct device *dev, long id, bool val);
>> +	bool default_val;
>> +	struct fwat_group_data group;
>> +};
>> +
>> +/**
>> + * struct fwat_enum_data - Data struct for the enumeration group type
>> + * @read: Read callback for the current_value attribute.
>> + * @write: Write callback for the current_value attribute.
>> + * @default_idx: Index of the default value in the @possible_vals array.
>> + * @possible_vals: Array of possible value strings for this group type.
>> + * @group: Group data.
>> + *
>> + * NOTE: The `val_idx` argument in the @write callback is guaranteed to be a
>> + *       valid (within bounds) index. However, the user is in charge of writing
>> + *       valid indexes to the `*val_idx` argument of the @read callback.
>> + *       Failing to do so may result in an OOB access.
>> + */
>> +struct fwat_enum_data {
>> +	int (*read)(struct device *dev, long id, int *val_idx);
>> +	int (*write)(struct device *dev, long id, int val_idx);
>> +	int default_idx;
>> +	const char * const *possible_vals;
>> +	struct fwat_group_data group;
>> +};
>> +
>> +/**
>> + * struct fwat_int_data - Data struct for the integer group type
>> + * @read: Read callback for the current_value attribute.
>> + * @write: Write callback for the current_value attribute.
>> + * @default_val: Default value.
>> + * @min_val: Minimum value.
>> + * @max_val: Maximum value.
>> + * @increment: Scalar increment for this value.
>> + * @group: Group data.
>> + *
>> + * NOTE: The @min_val, @max_val, @increment constraints are merely informative.
>> + *       These values are not enforced in any of the callbacks.
>> + */
>> +struct fwat_int_data {
>> +	int (*read)(struct device *dev, long id, long *val);
>> +	int (*write)(struct device *dev, long id, long val);
>> +	long default_val;
>> +	long min_val;
>> +	long max_val;
>> +	long increment;
>> +	struct fwat_group_data group;
>> +};
>> +
>> +/**
>> + * struct fwat_str_data - Data struct for the string group type
>> + * @read: Read callback for the current_value attribute.
>> + * @write: Write callback for the current_value attribute.
>> + * @default_val: Default value.
>> + * @min_len: Minimum string length.
>> + * @max_len: Maximum string length.
>> + * @group: Group data.
>> + *
>> + * NOTE: The @min_len, @max_len constraints are merely informative. These
>> + *       values are not enforced in any of the callbacks.
>> + */
>> +struct fwat_str_data {
>> +	int (*read)(struct device *dev, long id, const char **buf);
>> +	int (*write)(struct device *dev, long id, const char *buf);
>> +	const char *default_val;
>> +	long min_len;
>> +	long max_len;
>> +	struct fwat_group_data group;
>> +};
>> +
>> +#define __FWAT_GROUP(_name, _disp_name, _mode, _fattrs) \
>> +	{ .name = __stringify(_name), .display_name = _disp_name, .mode = _mode, .fattrs = _fattrs }
>> +
>> +/**
>> + * DEFINE_FWAT_BOOL_GROUP - Convenience macro to quickly define an static
>
> an static -> a static (all place)
>
>> + *                          struct fwat_bool_data instance
>> + * @_name: Name of the group.
>> + * @_disp_name: Name showed in the display_name attribute. (Optional)
>
> showed -> shown (all place)
>
>> + * @_def_val: Default value.
>> + * @_mode: Mode for the current_value attribute. All other attributes will have
>> + *         0444 permissions.
>> + * @_fattrs: Bitmap of selected attributes for this group type.
>> + *
>> + * `read` and `write` callbacks are required to be already defined as
>> + * `_name##_read` and `_name##_write` respectively.
>> + */
>> +#define DEFINE_FWAT_BOOL_GROUP(_name, _disp_name, _def_val, _mode, _fattrs) \
>> +	static const struct fwat_bool_data _name##_group_data = {	\
>> +		.read = _name##_read,					\
>> +		.write = _name##_write,					\
>> +		.default_val = _def_val,				\
>> +		.group = __FWAT_GROUP(_name, _disp_name, _mode, _fattrs), \
>> +	}
>> +
>> +/**
>> + * DEFINE_FWAT_ENUM_GROUP - Convenience macro to quickly define an static
>> + *                          struct fwat_enum_data instance
>> + * @_name: Name of the group.
>> + * @_disp_name: Name showed in the display_name attribute. (Optional)
>> + * @_def_idx: Index of the default value in the @_poss_vals array.
>> + * @_poss_vals: Array of possible value strings for this group type.
>> + * @_mode: Mode for the current_value attribute. All other attributes will have
>> + *         0444 permissions.
>> + * @_fattrs: Bitmap of selected attributes for this group type.
>> + *
>> + * `read` and `write` callbacks are required to be already defined as
>> + * `_name##_read` and `_name##_write` respectively.
>> + *
>> + * NOTE: The `val_idx` argument in the `write` callback is guaranteed to be a
>> + *       valid (within bounds) index. However, the user is in charge of writing
>> + *       valid indexes to the `*val_idx` argument of the `read` callback.
>> + *       Failing to do so may result in an OOB access.
>> + */
>> +#define DEFINE_FWAT_ENUM_GROUP(_name, _disp_name, _poss_vals, _def_idx, _mode, _fattrs) \
>> +	static const struct fwat_enum_data _name##_group_data = {	\
>> +		.read = _name##_read,					\
>> +		.write = _name##_write,					\
>> +		.default_idx = _def_idx,				\
>> +		.possible_vals = _poss_vals,				\
>> +		.group = __FWAT_GROUP(_name, _disp_name, _mode, _fattrs), \
>> +	}
>> +
>> +/**
>> + * DEFINE_FWAT_INT_GROUP - Convenience macro to quickly define an static
>> + *                         struct fwat_int_data instance
>> + * @_name: Name of the group.
>> + * @_disp_name: Name showed in the display_name attribute. (Optional)
>> + * @_def_val: Default value.
>> + * @_min: Minimum value.
>> + * @_max: Maximum value.
>> + * @_inc: Scalar increment for this value.
>> + * @_mode: Mode for the current_value attribute. All other attributes will have
>> + *         0444 permissions.
>> + * @_fattrs: Bitmap of selected attributes for this group type.
>> + *
>> + * `read` and `write` callbacks are required to be already defined as
>> + * `_name##_read` and `_name##_write` respectively.
>> + *
>> + * NOTE: The @_min, @_max, @_inc constraints are merely informative. These
>> + *       values are not enforced in any of the callbacks.
>> + */
>> +#define DEFINE_FWAT_INT_GROUP(_name, _disp_name, _def_val, _min, _max, _inc, _mode, _fattrs) \
>> +	static const struct fwat_int_data _name##_group_data = {	\
>> +		.read = _name##_read,					\
>> +		.write = _name##_write,					\
>> +		.default_val = _def_val,				\
>> +		.min_val = _min,					\
>> +		.max_val = _max,					\
>> +		.increment = _inc,					\
>> +		.group = __FWAT_GROUP(_name, _disp_name, _mode, _fattrs), \
>> +	}
>> +
>> +/**
>> + * DEFINE_FWAT_STR_GROUP - Convenience macro to quickly define an static
>> + *                         struct fwat_str_data instance
>> + * @_name: Name of the group.
>> + * @_disp_name: Name showed in the display_name attribute. (Optional)
>> + * @_def_val: Default value.
>> + * @_min: Minimum string length.
>> + * @_max: Maximum string length.
>> + * @_mode: Mode for the current_value attribute. All other attributes will have
>> + *         0444 permissions.
>> + * @_fattrs: Bitmap of selected attributes for this group type.
>> + *
>> + * `read` and `write` callbacks are required to be already defined as
>> + * `_name##_read` and `_name##_write` respectively.
>> + *
>> + * NOTE: The @_min, @_max constraints are merely informative. These values are
>> + *       not enforced in any of the callbacks.
>> + */
>> +#define DEFINE_FWAT_STR_GROUP(_name, _disp_name, _def_val, _min, _max, _mode, _fattrs) \
>> +	static const struct fwat_str_data _name##_group_data = {	\
>> +		.read = _name##_read,					\
>> +		.write = _name##_write,					\
>> +		.default_val = _def_val,				\
>> +		.min_len = _min,					\
>> +		.max_len = _max,					\
>> +		.group = __FWAT_GROUP(_name, _disp_name, _mode, _fattrs), \
>> +	}
>> +
>> +int fwat_create_bool_group(struct fwat_device *fadev,
>> +			   const struct fwat_bool_data *data);
>> +int fwat_create_enum_group(struct fwat_device *fadev,
>> +			   const struct fwat_enum_data *data);
>> +int fwat_create_int_group(struct fwat_device *fadev,
>> +			  const struct fwat_int_data *data);
>> +int fwat_create_str_group(struct fwat_device *fadev,
>> +			  const struct fwat_str_data *data);
>> +
>> +/**
>> + * fwat_create_group - Convenience generic macro to create a group
>> + * @_dev: fwat_device
>> + * @_data: One of fwat_{bool,enum,int,str}_data instance
>> + *
>> + * This macro (and associated functions) creates a sysfs group under the
>> + * 'attributes' directory, which is located in the class device root directory.
>> + *
>> + * See Documentation/ABI/testing/sysfs-class-firmware-attributes for details.
>> + *
>> + * The @_data associated with this group may be created either statically,
>> + * through DEFINE_FWAT_*_GROUP macros or dynamically, in which case the user
>> + * would have allocate and fill the struct manually. The dynamic approach should
>> + * be preferred when group constraints and/or visibility is decided dynamically.
>> + *
>> + * Example:
>> + *
>> + * static int stat_read(...){...};
>> + * static int stat_write(...){...};
>> + *
>> + * DEFINE_FWAT_(BOOL|ENUM|INT|STR)_GROUP(stat, ...);
>> + *
>> + * static int create_groups(struct fwat_device *fadev)
>> + * {
>> + *	struct fwat_enum_data *dyn_group_data;
>> + *
>> + *	dyn_group_data = kzalloc(...);
>> + *	// Fill the data
>> + *	...
>> + *	fwat_create_group(fadev, &stat_group_data);
>> + *	fwat_create_group(fadev, &dyn_group_data);
>> + *	fwat_create_group(...);
>> + *	...
>> + * }
>> + *
>> + * Return: 0 on success, -errno on failure
>> + */
>> +#define fwat_create_group(_dev, _data) \
>> +	_Generic((_data),							\
>> +		 const struct fwat_bool_data * : fwat_create_bool_group,	\
>> +		 const struct fwat_enum_data * : fwat_create_enum_group,	\
>> +		 const struct fwat_int_data * : fwat_create_int_group,		\
>> +		 const struct fwat_str_data * : fwat_create_str_group)		\
>> +		(_dev, _data)
>> +
>>   struct fwat_device * __must_check
>>   fwat_device_register(struct device *parent, const char *name, void *drvdata,
>>   		     const struct attribute_group **groups);
>> 
>
> Thanks
> Alok

Ack for everything. Thank you!


-- 
 ~ Kurt