Re: [PATCH 3/5] platform/x86: msi-ec: Filter out unsupported attributes

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

On Tue, 10 Oct 2023, Nikita Kravets wrote:

> Filter the attributes and only create those which are supported by the
> currently loaded configuration. The filtered attributes are saved in an
> attribute group to be easily created and removed.
> root_attrs_support is an array of all attributes and their support
> conditions. fw_version and fw_release_date are supported on all models
> so their condition is always true.
> 
> Cc: Aakash Singh <mail@singhaakash.dev>
> Cc: Jose Angel Pastrana <japp0005@red.ujaen.es>
> Signed-off-by: Nikita Kravets <teackot@gmail.com>
> ---
>  drivers/platform/x86/msi-ec.c | 40 +++++++++++++++++++++++++++--------
>  drivers/platform/x86/msi-ec.h |  5 +++++
>  2 files changed, 36 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/platform/x86/msi-ec.c b/drivers/platform/x86/msi-ec.c
> index 772b230fb47e..09472b21e093 100644
> --- a/drivers/platform/x86/msi-ec.c
> +++ b/drivers/platform/x86/msi-ec.c
> @@ -872,22 +872,44 @@ static ssize_t fw_release_date_show(struct device *device,
>  static DEVICE_ATTR_RO(fw_version);
>  static DEVICE_ATTR_RO(fw_release_date);
>  
> -static struct attribute *msi_root_attrs[] = {
> -	&dev_attr_fw_version.attr,
> -	&dev_attr_fw_release_date.attr,
> -	NULL
> -};
> -
> -static struct attribute_group msi_root_group = {
> -	.attrs = msi_root_attrs,
> -};
> +static struct attribute_group msi_root_group;
>  
>  /*
>   * Sysfs platform driver
>   */
>  
> +/*
> + * Copies supported attributes from `attributes` to `filtered`
> + */
> +static void filter_attributes(struct attribute_support *attributes,
> +			      struct attribute **filtered,
> +			      size_t size)
> +{
> +	for (int i = 0, j = 0; i < size; i++) {
> +		if (attributes[i].supported)
> +			filtered[j++] = attributes[i].attribute;
> +	}

Use .is_visible in the attribute group to toggle visibility.

> +}
> +
>  static int msi_platform_probe(struct platform_device *pdev)
>  {
> +	struct attribute_support root_attrs_support[] = {
> +		{
> +			&dev_attr_fw_version.attr,
> +			true,
> +		},
> +		{
> +			&dev_attr_fw_release_date.attr,
> +			true,
> +		},
> +	};
> +
> +	/* +1 to null-terminate the array */
> +	static struct attribute *root_attrs[ARRAY_SIZE(root_attrs_support) + 1] = {0};
> +
> +	filter_attributes(root_attrs_support, root_attrs, ARRAY_SIZE(root_attrs_support));
> +	msi_root_group.attrs = root_attrs;
> +
>  	return sysfs_create_group(&pdev->dev.kobj, &msi_root_group);
>  }
>  
> diff --git a/drivers/platform/x86/msi-ec.h b/drivers/platform/x86/msi-ec.h
> index be3533dc9cc6..f4198f0df5d9 100644
> --- a/drivers/platform/x86/msi-ec.h
> +++ b/drivers/platform/x86/msi-ec.h
> @@ -119,4 +119,9 @@ struct msi_ec_conf {
>  	struct msi_ec_kbd_bl_conf         kbd_bl;
>  };
>  
> +struct attribute_support {
> +	struct attribute *attribute;
> +	bool supported;
> +};
> +
>  #endif // _MSI_EC_H_
> 

-- 
 i.