Re: [PATCH v8 2/2] coresight: Add label sysfs node support

[Leo Yan <leo.yan@arm.com>]

On Thu, Jul 03, 2025 at 09:04:53PM +0800, Mao Jinlong wrote:

[...]

> +static ssize_t label_show(struct device *dev,
> +		struct device_attribute *attr, char *buf)
> +{
> +
> +	const char *str;
> +	int ret = 0;

No need to init ret to 0.

> +	ret = fwnode_property_read_string(dev_fwnode(dev), "label", &str);
> +	if (ret == 0)
> +		return scnprintf(buf, PAGE_SIZE, "%s\n", str);
> +	else
> +		return ret;
> +}
> +static DEVICE_ATTR_RO(label);
> +
>  static struct attribute *coresight_sink_attrs[] = {
>  	&dev_attr_enable_sink.attr,
> +	&dev_attr_label.attr,
>  	NULL,
>  };
>  ATTRIBUTE_GROUPS(coresight_sink);
>  
>  static struct attribute *coresight_source_attrs[] = {
>  	&dev_attr_enable_source.attr,
> +	&dev_attr_label.attr,
>  	NULL,
>  };
>  ATTRIBUTE_GROUPS(coresight_source);
>  
> +static struct attribute *coresight_link_attrs[] = {
> +	&dev_attr_label.attr,
> +	NULL,
> +};
> +ATTRIBUTE_GROUPS(coresight_link);
> +
> +static struct attribute *coresight_helper_attrs[] = {
> +	&dev_attr_label.attr,
> +	NULL,
> +};
> +ATTRIBUTE_GROUPS(coresight_helper);
> +

This change adds a 'label' entry for source, link, helper, and sink
components, but the documentation has only updated for three components:
CTI, funnel, and TPDM.

Should we also update the documentation for all relevant components,
such as ETM, ETR, etc.?

Additionally, patch 01 is missing the update to the ETM yaml file for
the new property. I checked patch v4 [1], which includes a change to
etm.yaml, but this change was dropped since v5. I briefly read the
v4 discussion thread and didn't see any mention of removing the ETM
related change. Did you see any particular issue when add label for
ETM devices?

Overall, this series is fine for me. Just please ensure that all
relevant components are covered for completeness.

Thanks,
Leo

[1] https://patchwork.kernel.org/project/linux-arm-msm/cover/20240703122340.26864-1-quic_jinlmao@quicinc.com/

>  const struct device_type coresight_dev_type[] = {
>  	[CORESIGHT_DEV_TYPE_SINK] = {
>  		.name = "sink",
> @@ -390,6 +420,7 @@ const struct device_type coresight_dev_type[] = {
>  	},
>  	[CORESIGHT_DEV_TYPE_LINK] = {
>  		.name = "link",
> +		.groups = coresight_link_groups,
>  	},
>  	[CORESIGHT_DEV_TYPE_LINKSINK] = {
>  		.name = "linksink",
> @@ -401,6 +432,7 @@ const struct device_type coresight_dev_type[] = {
>  	},
>  	[CORESIGHT_DEV_TYPE_HELPER] = {
>  		.name = "helper",
> +		.groups = coresight_helper_groups,
>  	}
>  };
>  /* Ensure the enum matches the names and groups */
> -- 
> 2.17.1
> 
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