Add an alternative filesystem view for the discovered Data Events, where
the tree of DEs is laid out following the discovered topological order
instead of the existing flat layout.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v1 --> v2
 - Use new FS API
 - Introduce new stlmfs_lookup_by_name helper
---
 .../firmware/arm_scmi/scmi_system_telemetry.c | 684 ++++++++++++++++++
 1 file changed, 684 insertions(+)

diff --git a/drivers/firmware/arm_scmi/scmi_system_telemetry.c b/drivers/firmware/arm_scmi/scmi_system_telemetry.c
index 721de615bec3..1221520356fd 100644
--- a/drivers/firmware/arm_scmi/scmi_system_telemetry.c
+++ b/drivers/firmware/arm_scmi/scmi_system_telemetry.c
@@ -174,6 +174,7 @@ struct scmi_tlm_inode {
  * @top_dentry: A reference to the top dentry for this instance.
  * @des_dentry: A reference to the DES dentry for this instance.
  * @grps_dentry: A reference to the groups dentry for this instance.
+ * @compo_dentry: A reference to the components dentry for this instance.
  * @info: A handy reference to this instance SCMI Telemetry info data.
  *
  */
@@ -188,6 +189,7 @@ struct scmi_tlm_instance {
 	struct dentry *top_dentry;
 	struct dentry *des_dentry;
 	struct dentry *grps_dentry;
+	struct dentry *compo_dentry;
 	const struct scmi_telemetry_info *info;
 };
 
@@ -196,6 +198,526 @@ static int scmi_telemetry_instance_register(struct super_block *sb,
 
 static LIST_HEAD(scmi_telemetry_instances);
 
+#define TYPES_ARRAY_SZ		256
+
+static const char *compo_types[TYPES_ARRAY_SZ] = {
+	"unspec",
+	"cpu",
+	"cluster",
+	"gpu",
+	"npu",
+	"interconnnect",
+	"mem_cntrl",
+	"l1_cache",
+	"l2_cache",
+	"l3_cache",
+	"ll_cache",
+	"sys_cache",
+	"disp_cntrl",
+	"ipu",
+	"chiplet",
+	"package",
+	"soc",
+	"system",
+	"smcu",
+	"accel",
+	"battery",
+	"charger",
+	"pmic",
+	"board",
+	"memory",
+	"periph",
+	"periph_subc",
+	"lid",
+	"display",
+	"res_29",
+	"res_30",
+	"res_31",
+	"res_32",
+	"res_33",
+	"res_34",
+	"res_35",
+	"res_36",
+	"res_37",
+	"res_38",
+	"res_39",
+	"res_40",
+	"res_41",
+	"res_42",
+	"res_43",
+	"res_44",
+	"res_45",
+	"res_46",
+	"res_47",
+	"res_48",
+	"res_49",
+	"res_50",
+	"res_51",
+	"res_52",
+	"res_53",
+	"res_54",
+	"res_55",
+	"res_56",
+	"res_57",
+	"res_58",
+	"res_59",
+	"res_60",
+	"res_61",
+	"res_62",
+	"res_63",
+	"res_64",
+	"res_65",
+	"res_66",
+	"res_67",
+	"res_68",
+	"res_69",
+	"res_70",
+	"res_71",
+	"res_72",
+	"res_73",
+	"res_74",
+	"res_75",
+	"res_76",
+	"res_77",
+	"res_78",
+	"res_79",
+	"res_80",
+	"res_81",
+	"res_82",
+	"res_83",
+	"res_84",
+	"res_85",
+	"res_86",
+	"res_87",
+	"res_88",
+	"res_89",
+	"res_90",
+	"res_91",
+	"res_92",
+	"res_93",
+	"res_94",
+	"res_95",
+	"res_96",
+	"res_97",
+	"res_98",
+	"res_99",
+	"res_100",
+	"res_101",
+	"res_102",
+	"res_103",
+	"res_104",
+	"res_105",
+	"res_106",
+	"res_107",
+	"res_108",
+	"res_109",
+	"res_110",
+	"res_111",
+	"res_112",
+	"res_113",
+	"res_114",
+	"res_115",
+	"res_116",
+	"res_117",
+	"res_118",
+	"res_119",
+	"res_120",
+	"res_121",
+	"res_122",
+	"res_123",
+	"res_124",
+	"res_125",
+	"res_126",
+	"res_127",
+	"res_128",
+	"res_129",
+	"res_130",
+	"res_131",
+	"res_132",
+	"res_133",
+	"res_134",
+	"res_135",
+	"res_136",
+	"res_137",
+	"res_138",
+	"res_139",
+	"res_140",
+	"res_141",
+	"res_142",
+	"res_143",
+	"res_144",
+	"res_145",
+	"res_146",
+	"res_147",
+	"res_148",
+	"res_149",
+	"res_150",
+	"res_151",
+	"res_152",
+	"res_153",
+	"res_154",
+	"res_155",
+	"res_156",
+	"res_157",
+	"res_158",
+	"res_159",
+	"res_160",
+	"res_161",
+	"res_162",
+	"res_163",
+	"res_164",
+	"res_165",
+	"res_166",
+	"res_167",
+	"res_168",
+	"res_169",
+	"res_170",
+	"res_171",
+	"res_172",
+	"res_173",
+	"res_174",
+	"res_175",
+	"res_176",
+	"res_177",
+	"res_178",
+	"res_179",
+	"res_180",
+	"res_181",
+	"res_182",
+	"res_183",
+	"res_184",
+	"res_185",
+	"res_186",
+	"res_187",
+	"res_188",
+	"res_189",
+	"res_190",
+	"res_191",
+	"res_192",
+	"res_193",
+	"res_194",
+	"res_195",
+	"res_196",
+	"res_197",
+	"res_198",
+	"res_199",
+	"res_200",
+	"res_201",
+	"res_202",
+	"res_203",
+	"res_204",
+	"res_205",
+	"res_206",
+	"res_207",
+	"res_208",
+	"res_209",
+	"res_210",
+	"res_211",
+	"res_212",
+	"res_213",
+	"res_214",
+	"res_215",
+	"res_216",
+	"res_217",
+	"res_218",
+	"res_219",
+	"res_220",
+	"res_221",
+	"res_222",
+	"res_223",
+	"oem_224",
+	"oem_225",
+	"oem_226",
+	"oem_227",
+	"oem_228",
+	"oem_229",
+	"oem_230",
+	"oem_231",
+	"oem_232",
+	"oem_233",
+	"oem_234",
+	"oem_235",
+	"oem_236",
+	"oem_237",
+	"oem_238",
+	"oem_239",
+	"oem_240",
+	"oem_241",
+	"oem_242",
+	"oem_243",
+	"oem_244",
+	"oem_245",
+	"oem_246",
+	"oem_247",
+	"oem_248",
+	"oem_249",
+	"oem_250",
+	"oem_251",
+	"oem_252",
+	"oem_253",
+	"oem_254",
+	"oem_255",
+};
+
+static const char *unit_types[TYPES_ARRAY_SZ] = {
+	"none",
+	"unspec",
+	"celsius",
+	"fahrenheit",
+	"kelvin",
+	"volts",
+	"amps",
+	"watts",
+	"joules",
+	"coulombs",
+	"va",
+	"nits",
+	"lumens",
+	"lux",
+	"candelas",
+	"kpa",
+	"psi",
+	"newtons",
+	"cfm",
+	"rpm",
+	"hertz",
+	"seconds",
+	"minutes",
+	"hours",
+	"days",
+	"weeks",
+	"mils",
+	"inches",
+	"feet",
+	"cubic_inches",
+	"cubic_feet",
+	"meters",
+	"cubic_centimeters",
+	"cubic_meters",
+	"liters",
+	"fluid_ounces",
+	"radians",
+	"steradians",
+	"revolutions",
+	"cycles",
+	"gravities",
+	"ounces",
+	"pounds",
+	"foot_pounds",
+	"ounce_inches",
+	"gauss",
+	"gilberts",
+	"henries",
+	"farads",
+	"ohms",
+	"siemens",
+	"moles",
+	"becquerels",
+	"ppm",
+	"decibels",
+	"dba",
+	"dbc",
+	"grays",
+	"sieverts",
+	"color_temp_kelvin",
+	"bits",
+	"bytes",
+	"words",
+	"dwords",
+	"qwords",
+	"percentage",
+	"pascals",
+	"counts",
+	"grams",
+	"newton_meters",
+	"hits",
+	"misses",
+	"retries",
+	"overruns",
+	"underruns",
+	"collisions",
+	"packets",
+	"messages",
+	"chars",
+	"errors",
+	"corrected_err",
+	"uncorrectable_err",
+	"square_mils",
+	"square_inches",
+	"square_feet",
+	"square_centimeters",
+	"square_meters",
+	"radians_per_secs",
+	"beats_per_minute",
+	"meters_per_secs_squared",
+	"meters_per_secs",
+	"cubic_meter_per_secs",
+	"millimeters_mercury",
+	"radians_per_secs_squared",
+	"state",
+	"bps",
+	"res_96",
+	"res_97",
+	"res_98",
+	"res_99",
+	"res_100",
+	"res_101",
+	"res_102",
+	"res_103",
+	"res_104",
+	"res_105",
+	"res_106",
+	"res_107",
+	"res_108",
+	"res_109",
+	"res_110",
+	"res_111",
+	"res_112",
+	"res_113",
+	"res_114",
+	"res_115",
+	"res_116",
+	"res_117",
+	"res_118",
+	"res_119",
+	"res_120",
+	"res_121",
+	"res_122",
+	"res_123",
+	"res_124",
+	"res_125",
+	"res_126",
+	"res_127",
+	"res_128",
+	"res_129",
+	"res_130",
+	"res_131",
+	"res_132",
+	"res_133",
+	"res_134",
+	"res_135",
+	"res_136",
+	"res_137",
+	"res_138",
+	"res_139",
+	"res_140",
+	"res_141",
+	"res_142",
+	"res_143",
+	"res_144",
+	"res_145",
+	"res_146",
+	"res_147",
+	"res_148",
+	"res_149",
+	"res_150",
+	"res_151",
+	"res_152",
+	"res_153",
+	"res_154",
+	"res_155",
+	"res_156",
+	"res_157",
+	"res_158",
+	"res_159",
+	"res_160",
+	"res_161",
+	"res_162",
+	"res_163",
+	"res_164",
+	"res_165",
+	"res_166",
+	"res_167",
+	"res_168",
+	"res_169",
+	"res_170",
+	"res_171",
+	"res_172",
+	"res_173",
+	"res_174",
+	"res_175",
+	"res_176",
+	"res_177",
+	"res_178",
+	"res_179",
+	"res_180",
+	"res_181",
+	"res_182",
+	"res_183",
+	"res_184",
+	"res_185",
+	"res_186",
+	"res_187",
+	"res_188",
+	"res_189",
+	"res_190",
+	"res_191",
+	"res_192",
+	"res_193",
+	"res_194",
+	"res_195",
+	"res_196",
+	"res_197",
+	"res_198",
+	"res_199",
+	"res_200",
+	"res_201",
+	"res_202",
+	"res_203",
+	"res_204",
+	"res_205",
+	"res_206",
+	"res_207",
+	"res_208",
+	"res_209",
+	"res_210",
+	"res_211",
+	"res_212",
+	"res_213",
+	"res_214",
+	"res_215",
+	"res_216",
+	"res_217",
+	"res_218",
+	"res_219",
+	"res_220",
+	"res_221",
+	"res_222",
+	"res_223",
+	"res_224",
+	"res_225",
+	"res_226",
+	"res_227",
+	"res_228",
+	"res_229",
+	"res_230",
+	"res_231",
+	"res_232",
+	"res_233",
+	"res_234",
+	"res_235",
+	"res_236",
+	"res_237",
+	"res_238",
+	"res_239",
+	"res_240",
+	"res_241",
+	"res_242",
+	"res_243",
+	"res_244",
+	"res_245",
+	"res_246",
+	"res_247",
+	"res_248",
+	"res_249",
+	"res_250",
+	"res_251",
+	"res_252",
+	"res_253",
+	"res_254",
+	"oem_unit",
+};
+
 static struct inode *stlmfs_get_inode(struct super_block *sb)
 {
 	struct inode *inode = new_inode(sb);
@@ -815,6 +1337,18 @@ DEFINE_TLM_CLASS(persistent_tlmo, "persistent", 0,
 DEFINE_TLM_CLASS(value_tlmo, "value", 0,
 		 S_IFREG | S_IRUSR, &de_read_fops, NULL);
 
+static inline struct dentry *
+stlmfs_lookup_by_name(struct dentry *parent, const char *dname)
+{
+	struct qstr qstr;
+
+	qstr.name = dname;
+	qstr.len = strlen(dname);
+	qstr.hash = full_name_hash(parent, qstr.name, qstr.len);
+
+	return d_lookup(parent, &qstr);
+}
+
 static int scmi_telemetry_de_populate(struct super_block *sb,
 				      struct scmi_tlm_setup *tsp,
 				      struct dentry *parent,
@@ -1659,6 +2193,150 @@ static struct dentry *stlmfs_create_root_dentry(struct super_block *sb)
 	return dentry;
 }
 
+static int scmi_telemetry_de_subdir_symlink(struct super_block *sb,
+					    struct scmi_tlm_setup *tsp,
+					    const struct scmi_telemetry_de *de,
+					    struct dentry *parent)
+{
+	struct dentry *dentry;
+	struct inode *inode;
+	int ret;
+
+	if (IS_ERR(parent))
+		return 0;
+
+	char *name __free(kfree) = kasprintf(GFP_KERNEL, "0x%08X", de->info->id);
+	if (!name)
+		return -ENOMEM;
+
+	char *link __free(kfree) =
+		kasprintf(GFP_KERNEL, "../../../../../des/0x%08X", de->info->id);
+	if (!link)
+		return -ENOMEM;
+
+	dentry = simple_start_creating(parent, name);
+	if (IS_ERR(dentry))
+		return PTR_ERR(dentry);
+
+	inode = stlmfs_get_inode(sb);
+	if (unlikely(!inode)) {
+		dev_err(tsp->dev,
+			"out of free dentries, cannot create '%s'", name);
+		return stlmfs_failed_creating(dentry);
+	}
+
+	inode->i_mode = S_IFLNK | 0777;
+	inode->i_op = &simple_symlink_inode_operations;
+	inode_init_owner(&nop_mnt_idmap, inode, NULL, inode->i_mode);
+	inode->i_link = no_free_ptr(link);
+
+	//d_add(dentry, inode);
+	d_make_persistent(dentry, inode);
+
+	simple_done_creating(dentry);
+
+	return ret;
+}
+
+static struct dentry *
+scmi_telemetry_topology_path_get(struct super_block *sb,
+				 struct scmi_tlm_setup *tsp,
+				 struct dentry *parent, const char *dname)
+{
+	struct dentry *dentry;
+
+	dentry = stlmfs_lookup_by_name(parent, dname);
+	if (!dentry) {
+		struct scmi_tlm_class *dir_tlm_cls __free(kfree) =
+			kzalloc(sizeof(*dir_tlm_cls), GFP_KERNEL);
+		if (!dir_tlm_cls)
+			return NULL;
+
+		dir_tlm_cls->name = kasprintf(GFP_KERNEL, "%s", dname);
+		if (!dir_tlm_cls->name)
+			return NULL;
+
+		dir_tlm_cls->mode = S_IFDIR | S_IRWXU;
+		dir_tlm_cls->flags = TLM_IS_DYNAMIC;
+
+		dentry = stlmfs_create_dentry(sb, tsp, parent,
+					      dir_tlm_cls, NULL);
+		if (!IS_ERR(dentry))
+			retain_and_null_ptr(dir_tlm_cls);
+	}
+
+	return dentry;
+}
+
+static int scmi_telemetry_topology_add_node(struct super_block *sb,
+					    struct scmi_tlm_instance *ti,
+					    const struct scmi_telemetry_de *de)
+{
+	struct dentry *ctype, *cinst, *cunit, *dinst;
+	struct scmi_tlm_de_info *dei = de->info;
+	char inst_str[32];
+	int ret;
+
+	/* by_compo_type/<COMPO_TYPE_STR>/ */
+	ctype = scmi_telemetry_topology_path_get(sb, ti->tsp, ti->compo_dentry,
+						 compo_types[dei->compo_type]);
+	if (!ctype)
+		return -ENOMEM;
+
+	/* by_compo_type/<COMPO_TYPE_STR>/<N>/ */
+	snprintf(inst_str, 32, "%u", dei->compo_instance_id);
+	cinst = scmi_telemetry_topology_path_get(sb, ti->tsp, ctype, inst_str);
+	dput(ctype);
+	if (!cinst)
+		return -ENOMEM;
+
+	/* by_compo_type/<COMPO_TYPE_STR>/<N>/<DE_UNIT_TYPE_STR>/ */
+	cunit = scmi_telemetry_topology_path_get(sb, ti->tsp, cinst,
+						 unit_types[dei->unit]);
+	dput(cinst);
+	if (!cunit)
+		return -ENOMEM;
+
+	/* by_compo_type/<COMPO_TYPE_STR>/<N>/<DE_UNIT_TYPE_STR>/<N> */
+	snprintf(inst_str, 32, "%u", dei->instance_id);
+	dinst = scmi_telemetry_topology_path_get(sb, ti->tsp, cunit, inst_str);
+	dput(cunit);
+	if (!dinst)
+		return -ENOMEM;
+
+	ret = scmi_telemetry_de_subdir_symlink(sb, ti->tsp, de, dinst);
+	dput(dinst);
+
+	return ret;
+}
+
+DEFINE_TLM_CLASS(compo_dir_cls, "components", 0, S_IFDIR | S_IRWXU, NULL, NULL);
+
+static int scmi_telemetry_topology_view_add(struct scmi_tlm_instance *ti)
+{
+	const struct scmi_telemetry_res_info *rinfo;
+	struct scmi_tlm_setup *tsp = ti->tsp;
+	struct device *dev = tsp->dev;
+
+	rinfo = scmi_telemetry_res_info_get(tsp);
+	if (!rinfo || !rinfo->fully_enumerated)
+		return -ENODEV;
+
+	ti->compo_dentry =
+		stlmfs_create_dentry(ti->sb, tsp, ti->top_dentry, &compo_dir_cls, NULL);
+
+	for (int i = 0; i < rinfo->num_des; i++) {
+		int ret;
+
+		ret = scmi_telemetry_topology_add_node(ti->sb, ti, rinfo->des[i]);
+		if (ret)
+			dev_err(dev, "Fail to add node %s to topology. Skip.\n",
+				rinfo->des[i]->info->name);
+	}
+
+	return 0;
+}
+
 static int scmi_tlm_root_dentries_initialize(struct scmi_tlm_instance *ti)
 {
 	struct scmi_tlm_setup *tsp = ti->tsp;
@@ -1712,6 +2390,12 @@ static int scmi_telemetry_instance_register(struct super_block *sb,
 			 ti->top_cls.name);
 	}
 
+	ret = scmi_telemetry_topology_view_add(ti);
+	if (ret)
+		dev_warn(ti->tsp->dev,
+			 "Failed to create topology view for instance %s.\n",
+			 ti->top_cls.name);
+
 	return 0;
 }
 
-- 
2.52.0

Hi Cristian,

On 14/01/2026 11:46, Cristian Marussi wrote:
> Add an alternative filesystem view for the discovered Data Events, where
> the tree of DEs is laid out following the discovered topological order
> instead of the existing flat layout.
> 
> Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
> ---
> v1 --> v2
>  - Use new FS API
>  - Introduce new stlmfs_lookup_by_name helper
> ---
>  .../firmware/arm_scmi/scmi_system_telemetry.c | 684 ++++++++++++++++++
>  1 file changed, 684 insertions(+)
> 
> diff --git a/drivers/firmware/arm_scmi/scmi_system_telemetry.c b/drivers/firmware/arm_scmi/scmi_system_telemetry.c
> index 721de615bec3..1221520356fd 100644
> --- a/drivers/firmware/arm_scmi/scmi_system_telemetry.c
> +++ b/drivers/firmware/arm_scmi/scmi_system_telemetry.c
> @@ -174,6 +174,7 @@ struct scmi_tlm_inode {
>   * @top_dentry: A reference to the top dentry for this instance.
>   * @des_dentry: A reference to the DES dentry for this instance.
>   * @grps_dentry: A reference to the groups dentry for this instance.
> + * @compo_dentry: A reference to the components dentry for this instance.
>   * @info: A handy reference to this instance SCMI Telemetry info data.
>   *
>   */
> @@ -188,6 +189,7 @@ struct scmi_tlm_instance {
>  	struct dentry *top_dentry;
>  	struct dentry *des_dentry;
>  	struct dentry *grps_dentry;
> +	struct dentry *compo_dentry;
>  	const struct scmi_telemetry_info *info;
>  };
>  
> @@ -196,6 +198,526 @@ static int scmi_telemetry_instance_register(struct super_block *sb,
>  
>  static LIST_HEAD(scmi_telemetry_instances);
>  
> +#define TYPES_ARRAY_SZ		256
> +
> +static const char *compo_types[TYPES_ARRAY_SZ] = {
> +	"unspec",
> +	"cpu",
> +	"cluster",
> +	"gpu",
> +	"npu",
> +	"interconnnect",
> +	"mem_cntrl",
> +	"l1_cache",
> +	"l2_cache",
> +	"l3_cache",
> +	"ll_cache",
> +	"sys_cache",
> +	"disp_cntrl",
> +	"ipu",
> +	"chiplet",
> +	"package",
> +	"soc",
> +	"system",
> +	"smcu",
> +	"accel",
> +	"battery",
> +	"charger",
> +	"pmic",
> +	"board",
> +	"memory",
> +	"periph",
> +	"periph_subc",
> +	"lid",
> +	"display",
> +	"res_29",
> +	"res_30",
> +	"res_31",
> +	"res_32",
> +	"res_33",
> +	"res_34",
> +	"res_35",
> +	"res_36",
> +	"res_37",
> +	"res_38",
> +	"res_39",
> +	"res_40",
> +	"res_41",
> +	"res_42",
> +	"res_43",
> +	"res_44",
> +	"res_45",
> +	"res_46",
> +	"res_47",
> +	"res_48",
> +	"res_49",
> +	"res_50",
> +	"res_51",
> +	"res_52",
> +	"res_53",
> +	"res_54",
> +	"res_55",
> +	"res_56",
> +	"res_57",
> +	"res_58",
> +	"res_59",
> +	"res_60",
> +	"res_61",
> +	"res_62",
> +	"res_63",
> +	"res_64",
> +	"res_65",
> +	"res_66",
> +	"res_67",
> +	"res_68",
> +	"res_69",
> +	"res_70",
> +	"res_71",
> +	"res_72",
> +	"res_73",
> +	"res_74",
> +	"res_75",
> +	"res_76",
> +	"res_77",
> +	"res_78",
> +	"res_79",
> +	"res_80",
> +	"res_81",
> +	"res_82",
> +	"res_83",
> +	"res_84",
> +	"res_85",
> +	"res_86",
> +	"res_87",
> +	"res_88",
> +	"res_89",
> +	"res_90",
> +	"res_91",
> +	"res_92",
> +	"res_93",
> +	"res_94",
> +	"res_95",
> +	"res_96",
> +	"res_97",
> +	"res_98",
> +	"res_99",
> +	"res_100",
> +	"res_101",
> +	"res_102",
> +	"res_103",
> +	"res_104",
> +	"res_105",
> +	"res_106",
> +	"res_107",
> +	"res_108",
> +	"res_109",
> +	"res_110",
> +	"res_111",
> +	"res_112",
> +	"res_113",
> +	"res_114",
> +	"res_115",
> +	"res_116",
> +	"res_117",
> +	"res_118",
> +	"res_119",
> +	"res_120",
> +	"res_121",
> +	"res_122",
> +	"res_123",
> +	"res_124",
> +	"res_125",
> +	"res_126",
> +	"res_127",
> +	"res_128",
> +	"res_129",
> +	"res_130",
> +	"res_131",
> +	"res_132",
> +	"res_133",
> +	"res_134",
> +	"res_135",
> +	"res_136",
> +	"res_137",
> +	"res_138",
> +	"res_139",
> +	"res_140",
> +	"res_141",
> +	"res_142",
> +	"res_143",
> +	"res_144",
> +	"res_145",
> +	"res_146",
> +	"res_147",
> +	"res_148",
> +	"res_149",
> +	"res_150",
> +	"res_151",
> +	"res_152",
> +	"res_153",
> +	"res_154",
> +	"res_155",
> +	"res_156",
> +	"res_157",
> +	"res_158",
> +	"res_159",
> +	"res_160",
> +	"res_161",
> +	"res_162",
> +	"res_163",
> +	"res_164",
> +	"res_165",
> +	"res_166",
> +	"res_167",
> +	"res_168",
> +	"res_169",
> +	"res_170",
> +	"res_171",
> +	"res_172",
> +	"res_173",
> +	"res_174",
> +	"res_175",
> +	"res_176",
> +	"res_177",
> +	"res_178",
> +	"res_179",
> +	"res_180",
> +	"res_181",
> +	"res_182",
> +	"res_183",
> +	"res_184",
> +	"res_185",
> +	"res_186",
> +	"res_187",
> +	"res_188",
> +	"res_189",
> +	"res_190",
> +	"res_191",
> +	"res_192",
> +	"res_193",
> +	"res_194",
> +	"res_195",
> +	"res_196",
> +	"res_197",
> +	"res_198",
> +	"res_199",
> +	"res_200",
> +	"res_201",
> +	"res_202",
> +	"res_203",
> +	"res_204",
> +	"res_205",
> +	"res_206",
> +	"res_207",
> +	"res_208",
> +	"res_209",
> +	"res_210",
> +	"res_211",
> +	"res_212",
> +	"res_213",
> +	"res_214",
> +	"res_215",
> +	"res_216",
> +	"res_217",
> +	"res_218",
> +	"res_219",
> +	"res_220",
> +	"res_221",
> +	"res_222",
> +	"res_223",
> +	"oem_224",
> +	"oem_225",
> +	"oem_226",
> +	"oem_227",
> +	"oem_228",
> +	"oem_229",
> +	"oem_230",
> +	"oem_231",
> +	"oem_232",
> +	"oem_233",
> +	"oem_234",
> +	"oem_235",
> +	"oem_236",
> +	"oem_237",
> +	"oem_238",
> +	"oem_239",
> +	"oem_240",
> +	"oem_241",
> +	"oem_242",
> +	"oem_243",
> +	"oem_244",
> +	"oem_245",
> +	"oem_246",
> +	"oem_247",
> +	"oem_248",
> +	"oem_249",
> +	"oem_250",
> +	"oem_251",
> +	"oem_252",
> +	"oem_253",
> +	"oem_254",
> +	"oem_255",
> +};
> +
> +static const char *unit_types[TYPES_ARRAY_SZ] = {
> +	"none",
> +	"unspec",
> +	"celsius",
> +	"fahrenheit",
> +	"kelvin",
> +	"volts",
> +	"amps",
> +	"watts",
> +	"joules",
> +	"coulombs",
> +	"va",
> +	"nits",
> +	"lumens",
> +	"lux",
> +	"candelas",
> +	"kpa",
> +	"psi",
> +	"newtons",
> +	"cfm",
> +	"rpm",
> +	"hertz",
> +	"seconds",
> +	"minutes",
> +	"hours",
> +	"days",
> +	"weeks",
> +	"mils",
> +	"inches",
> +	"feet",
> +	"cubic_inches",
> +	"cubic_feet",
> +	"meters",
> +	"cubic_centimeters",
> +	"cubic_meters",
> +	"liters",
> +	"fluid_ounces",
> +	"radians",
> +	"steradians",
> +	"revolutions",
> +	"cycles",
> +	"gravities",
> +	"ounces",
> +	"pounds",
> +	"foot_pounds",
> +	"ounce_inches",
> +	"gauss",
> +	"gilberts",
> +	"henries",
> +	"farads",
> +	"ohms",
> +	"siemens",
> +	"moles",
> +	"becquerels",
> +	"ppm",
> +	"decibels",
> +	"dba",
> +	"dbc",
> +	"grays",
> +	"sieverts",
> +	"color_temp_kelvin",
> +	"bits",
> +	"bytes",
> +	"words",
> +	"dwords",
> +	"qwords",
> +	"percentage",
> +	"pascals",
> +	"counts",
> +	"grams",
> +	"newton_meters",
> +	"hits",
> +	"misses",
> +	"retries",
> +	"overruns",
> +	"underruns",
> +	"collisions",
> +	"packets",
> +	"messages",
> +	"chars",
> +	"errors",
> +	"corrected_err",
> +	"uncorrectable_err",
> +	"square_mils",
> +	"square_inches",
> +	"square_feet",
> +	"square_centimeters",
> +	"square_meters",
> +	"radians_per_secs",
> +	"beats_per_minute",
> +	"meters_per_secs_squared",
> +	"meters_per_secs",
> +	"cubic_meter_per_secs",
> +	"millimeters_mercury",
> +	"radians_per_secs_squared",
> +	"state",
> +	"bps",
> +	"res_96",
> +	"res_97",
> +	"res_98",
> +	"res_99",
> +	"res_100",
> +	"res_101",
> +	"res_102",
> +	"res_103",
> +	"res_104",
> +	"res_105",
> +	"res_106",
> +	"res_107",
> +	"res_108",
> +	"res_109",
> +	"res_110",
> +	"res_111",
> +	"res_112",
> +	"res_113",
> +	"res_114",
> +	"res_115",
> +	"res_116",
> +	"res_117",
> +	"res_118",
> +	"res_119",
> +	"res_120",
> +	"res_121",
> +	"res_122",
> +	"res_123",
> +	"res_124",
> +	"res_125",
> +	"res_126",
> +	"res_127",
> +	"res_128",
> +	"res_129",
> +	"res_130",
> +	"res_131",
> +	"res_132",
> +	"res_133",
> +	"res_134",
> +	"res_135",
> +	"res_136",
> +	"res_137",
> +	"res_138",
> +	"res_139",
> +	"res_140",
> +	"res_141",
> +	"res_142",
> +	"res_143",
> +	"res_144",
> +	"res_145",
> +	"res_146",
> +	"res_147",
> +	"res_148",
> +	"res_149",
> +	"res_150",
> +	"res_151",
> +	"res_152",
> +	"res_153",
> +	"res_154",
> +	"res_155",
> +	"res_156",
> +	"res_157",
> +	"res_158",
> +	"res_159",
> +	"res_160",
> +	"res_161",
> +	"res_162",
> +	"res_163",
> +	"res_164",
> +	"res_165",
> +	"res_166",
> +	"res_167",
> +	"res_168",
> +	"res_169",
> +	"res_170",
> +	"res_171",
> +	"res_172",
> +	"res_173",
> +	"res_174",
> +	"res_175",
> +	"res_176",
> +	"res_177",
> +	"res_178",
> +	"res_179",
> +	"res_180",
> +	"res_181",
> +	"res_182",
> +	"res_183",
> +	"res_184",
> +	"res_185",
> +	"res_186",
> +	"res_187",
> +	"res_188",
> +	"res_189",
> +	"res_190",
> +	"res_191",
> +	"res_192",
> +	"res_193",
> +	"res_194",
> +	"res_195",
> +	"res_196",
> +	"res_197",
> +	"res_198",
> +	"res_199",
> +	"res_200",
> +	"res_201",
> +	"res_202",
> +	"res_203",
> +	"res_204",
> +	"res_205",
> +	"res_206",
> +	"res_207",
> +	"res_208",
> +	"res_209",
> +	"res_210",
> +	"res_211",
> +	"res_212",
> +	"res_213",
> +	"res_214",
> +	"res_215",
> +	"res_216",
> +	"res_217",
> +	"res_218",
> +	"res_219",
> +	"res_220",
> +	"res_221",
> +	"res_222",
> +	"res_223",
> +	"res_224",
> +	"res_225",
> +	"res_226",
> +	"res_227",
> +	"res_228",
> +	"res_229",
> +	"res_230",
> +	"res_231",
> +	"res_232",
> +	"res_233",
> +	"res_234",
> +	"res_235",
> +	"res_236",
> +	"res_237",
> +	"res_238",
> +	"res_239",
> +	"res_240",
> +	"res_241",
> +	"res_242",
> +	"res_243",
> +	"res_244",
> +	"res_245",
> +	"res_246",
> +	"res_247",
> +	"res_248",
> +	"res_249",
> +	"res_250",
> +	"res_251",
> +	"res_252",
> +	"res_253",
> +	"res_254",
> +	"oem_unit",
> +};
> +
>  static struct inode *stlmfs_get_inode(struct super_block *sb)
>  {
>  	struct inode *inode = new_inode(sb);
> @@ -815,6 +1337,18 @@ DEFINE_TLM_CLASS(persistent_tlmo, "persistent", 0,
>  DEFINE_TLM_CLASS(value_tlmo, "value", 0,
>  		 S_IFREG | S_IRUSR, &de_read_fops, NULL);
>  
> +static inline struct dentry *
> +stlmfs_lookup_by_name(struct dentry *parent, const char *dname)
> +{
> +	struct qstr qstr;
> +
> +	qstr.name = dname;
> +	qstr.len = strlen(dname);
> +	qstr.hash = full_name_hash(parent, qstr.name, qstr.len);
> +
> +	return d_lookup(parent, &qstr);
> +}
> +
>  static int scmi_telemetry_de_populate(struct super_block *sb,
>  				      struct scmi_tlm_setup *tsp,
>  				      struct dentry *parent,
> @@ -1659,6 +2193,150 @@ static struct dentry *stlmfs_create_root_dentry(struct super_block *sb)
>  	return dentry;
>  }
>  
> +static int scmi_telemetry_de_subdir_symlink(struct super_block *sb,
> +					    struct scmi_tlm_setup *tsp,
> +					    const struct scmi_telemetry_de *de,
> +					    struct dentry *parent)
> +{
> +	struct dentry *dentry;
> +	struct inode *inode;
> +	int ret;
I notice that ret isn't assigned a value and the function returns ret without
initialising.

> +
> +	if (IS_ERR(parent))
> +		return 0;
> +
> +	char *name __free(kfree) = kasprintf(GFP_KERNEL, "0x%08X", de->info->id);
> +	if (!name)
> +		return -ENOMEM;
> +
> +	char *link __free(kfree) =
> +		kasprintf(GFP_KERNEL, "../../../../../des/0x%08X", de->info->id);
> +	if (!link)
> +		return -ENOMEM;
> +
> +	dentry = simple_start_creating(parent, name);
> +	if (IS_ERR(dentry))
> +		return PTR_ERR(dentry);
> +
> +	inode = stlmfs_get_inode(sb);
> +	if (unlikely(!inode)) {
> +		dev_err(tsp->dev,
> +			"out of free dentries, cannot create '%s'", name);
> +		return stlmfs_failed_creating(dentry);
> +	}
> +
> +	inode->i_mode = S_IFLNK | 0777;
> +	inode->i_op = &simple_symlink_inode_operations;
> +	inode_init_owner(&nop_mnt_idmap, inode, NULL, inode->i_mode);
> +	inode->i_link = no_free_ptr(link);
> +
> +	//d_add(dentry, inode);
> +	d_make_persistent(dentry, inode);
> +
> +	simple_done_creating(dentry);
> +
> +	return ret;
> +}
> +
> +static struct dentry *
> +scmi_telemetry_topology_path_get(struct super_block *sb,
> +				 struct scmi_tlm_setup *tsp,
> +				 struct dentry *parent, const char *dname)
> +{
> +	struct dentry *dentry;
> +
> +	dentry = stlmfs_lookup_by_name(parent, dname);
> +	if (!dentry) {
> +		struct scmi_tlm_class *dir_tlm_cls __free(kfree) =
> +			kzalloc(sizeof(*dir_tlm_cls), GFP_KERNEL);
> +		if (!dir_tlm_cls)
> +			return NULL;
> +
> +		dir_tlm_cls->name = kasprintf(GFP_KERNEL, "%s", dname);
> +		if (!dir_tlm_cls->name)
> +			return NULL;
> +
> +		dir_tlm_cls->mode = S_IFDIR | S_IRWXU;
> +		dir_tlm_cls->flags = TLM_IS_DYNAMIC;
> +
> +		dentry = stlmfs_create_dentry(sb, tsp, parent,
> +					      dir_tlm_cls, NULL);
> +		if (!IS_ERR(dentry))
> +			retain_and_null_ptr(dir_tlm_cls);
> +	}
> +
> +	return dentry;
> +}
> +
> +static int scmi_telemetry_topology_add_node(struct super_block *sb,
> +					    struct scmi_tlm_instance *ti,
> +					    const struct scmi_telemetry_de *de)
> +{
> +	struct dentry *ctype, *cinst, *cunit, *dinst;
> +	struct scmi_tlm_de_info *dei = de->info;
> +	char inst_str[32];
> +	int ret;
> +
> +	/* by_compo_type/<COMPO_TYPE_STR>/ */
> +	ctype = scmi_telemetry_topology_path_get(sb, ti->tsp, ti->compo_dentry,
> +						 compo_types[dei->compo_type]);
> +	if (!ctype)
> +		return -ENOMEM;
> +
> +	/* by_compo_type/<COMPO_TYPE_STR>/<N>/ */
> +	snprintf(inst_str, 32, "%u", dei->compo_instance_id);
> +	cinst = scmi_telemetry_topology_path_get(sb, ti->tsp, ctype, inst_str);
> +	dput(ctype);
> +	if (!cinst)
> +		return -ENOMEM;
> +
> +	/* by_compo_type/<COMPO_TYPE_STR>/<N>/<DE_UNIT_TYPE_STR>/ */
> +	cunit = scmi_telemetry_topology_path_get(sb, ti->tsp, cinst,
> +						 unit_types[dei->unit]);
> +	dput(cinst);
> +	if (!cunit)
> +		return -ENOMEM;
> +
> +	/* by_compo_type/<COMPO_TYPE_STR>/<N>/<DE_UNIT_TYPE_STR>/<N> */
> +	snprintf(inst_str, 32, "%u", dei->instance_id);
> +	dinst = scmi_telemetry_topology_path_get(sb, ti->tsp, cunit, inst_str);
> +	dput(cunit);
> +	if (!dinst)
> +		return -ENOMEM;
> +
> +	ret = scmi_telemetry_de_subdir_symlink(sb, ti->tsp, de, dinst);
> +	dput(dinst);
> +
> +	return ret;
> +}
> +
> +DEFINE_TLM_CLASS(compo_dir_cls, "components", 0, S_IFDIR | S_IRWXU, NULL, NULL);
> +
> +static int scmi_telemetry_topology_view_add(struct scmi_tlm_instance *ti)
> +{
> +	const struct scmi_telemetry_res_info *rinfo;
> +	struct scmi_tlm_setup *tsp = ti->tsp;
> +	struct device *dev = tsp->dev;
> +
> +	rinfo = scmi_telemetry_res_info_get(tsp);
> +	if (!rinfo || !rinfo->fully_enumerated)
> +		return -ENODEV;
> +
> +	ti->compo_dentry =
> +		stlmfs_create_dentry(ti->sb, tsp, ti->top_dentry, &compo_dir_cls, NULL);
> +
> +	for (int i = 0; i < rinfo->num_des; i++) {
> +		int ret;
> +
> +		ret = scmi_telemetry_topology_add_node(ti->sb, ti, rinfo->des[i]);
> +		if (ret)
> +			dev_err(dev, "Fail to add node %s to topology. Skip.\n",
> +				rinfo->des[i]->info->name);
> +	}
> +
> +	return 0;
> +}
> +
>  static int scmi_tlm_root_dentries_initialize(struct scmi_tlm_instance *ti)
>  {
>  	struct scmi_tlm_setup *tsp = ti->tsp;
> @@ -1712,6 +2390,12 @@ static int scmi_telemetry_instance_register(struct super_block *sb,
>  			 ti->top_cls.name);
>  	}
>  
> +	ret = scmi_telemetry_topology_view_add(ti);
> +	if (ret)
> +		dev_warn(ti->tsp->dev,
> +			 "Failed to create topology view for instance %s.\n",
> +			 ti->top_cls.name);
> +
>  	return 0;
>  }
>  

I will continue reviewing,
Thanks,
Elif

On Fri, Jan 16, 2026 at 01:35:00PM +0000, Elif Topuz wrote:
> 
> Hi Cristian,

H Elif,

> 
> On 14/01/2026 11:46, Cristian Marussi wrote:
> > Add an alternative filesystem view for the discovered Data Events, where
> > the tree of DEs is laid out following the discovered topological order
> > instead of the existing flat layout.
> > 
> > Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
> > ---
> > v1 --> v2
> >  - Use new FS API
> >  - Introduce new stlmfs_lookup_by_name helper
> > ---
> >  .../firmware/arm_scmi/scmi_system_telemetry.c | 684 ++++++++++++++++++
> >  1 file changed, 684 insertions(+)
> > 
> > diff --git a/drivers/firmware/arm_scmi/scmi_system_telemetry.c b/drivers/firmware/arm_scmi/scmi_system_telemetry.c
> > index 721de615bec3..1221520356fd 100644
> > --- a/drivers/firmware/arm_scmi/scmi_system_telemetry.c
> > +++ b/drivers/firmware/arm_scmi/scmi_system_telemetry.c
> > @@ -174,6 +174,7 @@ struct scmi_tlm_inode {
> >   * @top_dentry: A reference to the top dentry for this instance.
> >   * @des_dentry: A reference to the DES dentry for this instance.
> >   * @grps_dentry: A reference to the groups dentry for this instance.
> > + * @compo_dentry: A reference to the components dentry for this instance.
> >   * @info: A handy reference to this instance SCMI Telemetry info data.
> >   *
> >   */
> > @@ -188,6 +189,7 @@ struct scmi_tlm_instance {
> >  	struct dentry *top_dentry;
> >  	struct dentry *des_dentry;
> >  	struct dentry *grps_dentry;
> > +	struct dentry *compo_dentry;
> >  	const struct scmi_telemetry_info *info;
> >  };
> >  
> > @@ -196,6 +198,526 @@ static int scmi_telemetry_instance_register(struct super_block *sb,
> >  
> >  static LIST_HEAD(scmi_telemetry_instances);
> >  
> > +#define TYPES_ARRAY_SZ		256
> > +
> > +static const char *compo_types[TYPES_ARRAY_SZ] = {
> > +	"unspec",
> > +	"cpu",
> > +	"cluster",
> > +	"gpu",
> > +	"npu",
> > +	"interconnnect",
> > +	"mem_cntrl",
> > +	"l1_cache",
> > +	"l2_cache",
> > +	"l3_cache",
> > +	"ll_cache",
> > +	"sys_cache",
> > +	"disp_cntrl",
> > +	"ipu",
> > +	"chiplet",
> > +	"package",
> > +	"soc",
> > +	"system",
> > +	"smcu",
> > +	"accel",
> > +	"battery",
> > +	"charger",
> > +	"pmic",
> > +	"board",
> > +	"memory",
> > +	"periph",
> > +	"periph_subc",
> > +	"lid",
> > +	"display",
> > +	"res_29",
> > +	"res_30",
> > +	"res_31",
> > +	"res_32",
> > +	"res_33",
> > +	"res_34",
> > +	"res_35",
> > +	"res_36",
> > +	"res_37",
> > +	"res_38",
> > +	"res_39",
> > +	"res_40",
> > +	"res_41",
> > +	"res_42",
> > +	"res_43",
> > +	"res_44",
> > +	"res_45",
> > +	"res_46",
> > +	"res_47",
> > +	"res_48",
> > +	"res_49",
> > +	"res_50",
> > +	"res_51",
> > +	"res_52",
> > +	"res_53",
> > +	"res_54",
> > +	"res_55",
> > +	"res_56",
> > +	"res_57",
> > +	"res_58",
> > +	"res_59",
> > +	"res_60",
> > +	"res_61",
> > +	"res_62",
> > +	"res_63",
> > +	"res_64",
> > +	"res_65",
> > +	"res_66",
> > +	"res_67",
> > +	"res_68",
> > +	"res_69",
> > +	"res_70",
> > +	"res_71",
> > +	"res_72",
> > +	"res_73",
> > +	"res_74",
> > +	"res_75",
> > +	"res_76",
> > +	"res_77",
> > +	"res_78",
> > +	"res_79",
> > +	"res_80",
> > +	"res_81",
> > +	"res_82",
> > +	"res_83",
> > +	"res_84",
> > +	"res_85",
> > +	"res_86",
> > +	"res_87",
> > +	"res_88",
> > +	"res_89",
> > +	"res_90",
> > +	"res_91",
> > +	"res_92",
> > +	"res_93",
> > +	"res_94",
> > +	"res_95",
> > +	"res_96",
> > +	"res_97",
> > +	"res_98",
> > +	"res_99",
> > +	"res_100",
> > +	"res_101",
> > +	"res_102",
> > +	"res_103",
> > +	"res_104",
> > +	"res_105",
> > +	"res_106",
> > +	"res_107",
> > +	"res_108",
> > +	"res_109",
> > +	"res_110",
> > +	"res_111",
> > +	"res_112",
> > +	"res_113",
> > +	"res_114",
> > +	"res_115",
> > +	"res_116",
> > +	"res_117",
> > +	"res_118",
> > +	"res_119",
> > +	"res_120",
> > +	"res_121",
> > +	"res_122",
> > +	"res_123",
> > +	"res_124",
> > +	"res_125",
> > +	"res_126",
> > +	"res_127",
> > +	"res_128",
> > +	"res_129",
> > +	"res_130",
> > +	"res_131",
> > +	"res_132",
> > +	"res_133",
> > +	"res_134",
> > +	"res_135",
> > +	"res_136",
> > +	"res_137",
> > +	"res_138",
> > +	"res_139",
> > +	"res_140",
> > +	"res_141",
> > +	"res_142",
> > +	"res_143",
> > +	"res_144",
> > +	"res_145",
> > +	"res_146",
> > +	"res_147",
> > +	"res_148",
> > +	"res_149",
> > +	"res_150",
> > +	"res_151",
> > +	"res_152",
> > +	"res_153",
> > +	"res_154",
> > +	"res_155",
> > +	"res_156",
> > +	"res_157",
> > +	"res_158",
> > +	"res_159",
> > +	"res_160",
> > +	"res_161",
> > +	"res_162",
> > +	"res_163",
> > +	"res_164",
> > +	"res_165",
> > +	"res_166",
> > +	"res_167",
> > +	"res_168",
> > +	"res_169",
> > +	"res_170",
> > +	"res_171",
> > +	"res_172",
> > +	"res_173",
> > +	"res_174",
> > +	"res_175",
> > +	"res_176",
> > +	"res_177",
> > +	"res_178",
> > +	"res_179",
> > +	"res_180",
> > +	"res_181",
> > +	"res_182",
> > +	"res_183",
> > +	"res_184",
> > +	"res_185",
> > +	"res_186",
> > +	"res_187",
> > +	"res_188",
> > +	"res_189",
> > +	"res_190",
> > +	"res_191",
> > +	"res_192",
> > +	"res_193",
> > +	"res_194",
> > +	"res_195",
> > +	"res_196",
> > +	"res_197",
> > +	"res_198",
> > +	"res_199",
> > +	"res_200",
> > +	"res_201",
> > +	"res_202",
> > +	"res_203",
> > +	"res_204",
> > +	"res_205",
> > +	"res_206",
> > +	"res_207",
> > +	"res_208",
> > +	"res_209",
> > +	"res_210",
> > +	"res_211",
> > +	"res_212",
> > +	"res_213",
> > +	"res_214",
> > +	"res_215",
> > +	"res_216",
> > +	"res_217",
> > +	"res_218",
> > +	"res_219",
> > +	"res_220",
> > +	"res_221",
> > +	"res_222",
> > +	"res_223",
> > +	"oem_224",
> > +	"oem_225",
> > +	"oem_226",
> > +	"oem_227",
> > +	"oem_228",
> > +	"oem_229",
> > +	"oem_230",
> > +	"oem_231",
> > +	"oem_232",
> > +	"oem_233",
> > +	"oem_234",
> > +	"oem_235",
> > +	"oem_236",
> > +	"oem_237",
> > +	"oem_238",
> > +	"oem_239",
> > +	"oem_240",
> > +	"oem_241",
> > +	"oem_242",
> > +	"oem_243",
> > +	"oem_244",
> > +	"oem_245",
> > +	"oem_246",
> > +	"oem_247",
> > +	"oem_248",
> > +	"oem_249",
> > +	"oem_250",
> > +	"oem_251",
> > +	"oem_252",
> > +	"oem_253",
> > +	"oem_254",
> > +	"oem_255",
> > +};
> > +
> > +static const char *unit_types[TYPES_ARRAY_SZ] = {
> > +	"none",
> > +	"unspec",
> > +	"celsius",
> > +	"fahrenheit",
> > +	"kelvin",
> > +	"volts",
> > +	"amps",
> > +	"watts",
> > +	"joules",
> > +	"coulombs",
> > +	"va",
> > +	"nits",
> > +	"lumens",
> > +	"lux",
> > +	"candelas",
> > +	"kpa",
> > +	"psi",
> > +	"newtons",
> > +	"cfm",
> > +	"rpm",
> > +	"hertz",
> > +	"seconds",
> > +	"minutes",
> > +	"hours",
> > +	"days",
> > +	"weeks",
> > +	"mils",
> > +	"inches",
> > +	"feet",
> > +	"cubic_inches",
> > +	"cubic_feet",
> > +	"meters",
> > +	"cubic_centimeters",
> > +	"cubic_meters",
> > +	"liters",
> > +	"fluid_ounces",
> > +	"radians",
> > +	"steradians",
> > +	"revolutions",
> > +	"cycles",
> > +	"gravities",
> > +	"ounces",
> > +	"pounds",
> > +	"foot_pounds",
> > +	"ounce_inches",
> > +	"gauss",
> > +	"gilberts",
> > +	"henries",
> > +	"farads",
> > +	"ohms",
> > +	"siemens",
> > +	"moles",
> > +	"becquerels",
> > +	"ppm",
> > +	"decibels",
> > +	"dba",
> > +	"dbc",
> > +	"grays",
> > +	"sieverts",
> > +	"color_temp_kelvin",
> > +	"bits",
> > +	"bytes",
> > +	"words",
> > +	"dwords",
> > +	"qwords",
> > +	"percentage",
> > +	"pascals",
> > +	"counts",
> > +	"grams",
> > +	"newton_meters",
> > +	"hits",
> > +	"misses",
> > +	"retries",
> > +	"overruns",
> > +	"underruns",
> > +	"collisions",
> > +	"packets",
> > +	"messages",
> > +	"chars",
> > +	"errors",
> > +	"corrected_err",
> > +	"uncorrectable_err",
> > +	"square_mils",
> > +	"square_inches",
> > +	"square_feet",
> > +	"square_centimeters",
> > +	"square_meters",
> > +	"radians_per_secs",
> > +	"beats_per_minute",
> > +	"meters_per_secs_squared",
> > +	"meters_per_secs",
> > +	"cubic_meter_per_secs",
> > +	"millimeters_mercury",
> > +	"radians_per_secs_squared",
> > +	"state",
> > +	"bps",
> > +	"res_96",
> > +	"res_97",
> > +	"res_98",
> > +	"res_99",
> > +	"res_100",
> > +	"res_101",
> > +	"res_102",
> > +	"res_103",
> > +	"res_104",
> > +	"res_105",
> > +	"res_106",
> > +	"res_107",
> > +	"res_108",
> > +	"res_109",
> > +	"res_110",
> > +	"res_111",
> > +	"res_112",
> > +	"res_113",
> > +	"res_114",
> > +	"res_115",
> > +	"res_116",
> > +	"res_117",
> > +	"res_118",
> > +	"res_119",
> > +	"res_120",
> > +	"res_121",
> > +	"res_122",
> > +	"res_123",
> > +	"res_124",
> > +	"res_125",
> > +	"res_126",
> > +	"res_127",
> > +	"res_128",
> > +	"res_129",
> > +	"res_130",
> > +	"res_131",
> > +	"res_132",
> > +	"res_133",
> > +	"res_134",
> > +	"res_135",
> > +	"res_136",
> > +	"res_137",
> > +	"res_138",
> > +	"res_139",
> > +	"res_140",
> > +	"res_141",
> > +	"res_142",
> > +	"res_143",
> > +	"res_144",
> > +	"res_145",
> > +	"res_146",
> > +	"res_147",
> > +	"res_148",
> > +	"res_149",
> > +	"res_150",
> > +	"res_151",
> > +	"res_152",
> > +	"res_153",
> > +	"res_154",
> > +	"res_155",
> > +	"res_156",
> > +	"res_157",
> > +	"res_158",
> > +	"res_159",
> > +	"res_160",
> > +	"res_161",
> > +	"res_162",
> > +	"res_163",
> > +	"res_164",
> > +	"res_165",
> > +	"res_166",
> > +	"res_167",
> > +	"res_168",
> > +	"res_169",
> > +	"res_170",
> > +	"res_171",
> > +	"res_172",
> > +	"res_173",
> > +	"res_174",
> > +	"res_175",
> > +	"res_176",
> > +	"res_177",
> > +	"res_178",
> > +	"res_179",
> > +	"res_180",
> > +	"res_181",
> > +	"res_182",
> > +	"res_183",
> > +	"res_184",
> > +	"res_185",
> > +	"res_186",
> > +	"res_187",
> > +	"res_188",
> > +	"res_189",
> > +	"res_190",
> > +	"res_191",
> > +	"res_192",
> > +	"res_193",
> > +	"res_194",
> > +	"res_195",
> > +	"res_196",
> > +	"res_197",
> > +	"res_198",
> > +	"res_199",
> > +	"res_200",
> > +	"res_201",
> > +	"res_202",
> > +	"res_203",
> > +	"res_204",
> > +	"res_205",
> > +	"res_206",
> > +	"res_207",
> > +	"res_208",
> > +	"res_209",
> > +	"res_210",
> > +	"res_211",
> > +	"res_212",
> > +	"res_213",
> > +	"res_214",
> > +	"res_215",
> > +	"res_216",
> > +	"res_217",
> > +	"res_218",
> > +	"res_219",
> > +	"res_220",
> > +	"res_221",
> > +	"res_222",
> > +	"res_223",
> > +	"res_224",
> > +	"res_225",
> > +	"res_226",
> > +	"res_227",
> > +	"res_228",
> > +	"res_229",
> > +	"res_230",
> > +	"res_231",
> > +	"res_232",
> > +	"res_233",
> > +	"res_234",
> > +	"res_235",
> > +	"res_236",
> > +	"res_237",
> > +	"res_238",
> > +	"res_239",
> > +	"res_240",
> > +	"res_241",
> > +	"res_242",
> > +	"res_243",
> > +	"res_244",
> > +	"res_245",
> > +	"res_246",
> > +	"res_247",
> > +	"res_248",
> > +	"res_249",
> > +	"res_250",
> > +	"res_251",
> > +	"res_252",
> > +	"res_253",
> > +	"res_254",
> > +	"oem_unit",
> > +};
> > +
> >  static struct inode *stlmfs_get_inode(struct super_block *sb)
> >  {
> >  	struct inode *inode = new_inode(sb);
> > @@ -815,6 +1337,18 @@ DEFINE_TLM_CLASS(persistent_tlmo, "persistent", 0,
> >  DEFINE_TLM_CLASS(value_tlmo, "value", 0,
> >  		 S_IFREG | S_IRUSR, &de_read_fops, NULL);
> >  
> > +static inline struct dentry *
> > +stlmfs_lookup_by_name(struct dentry *parent, const char *dname)
> > +{
> > +	struct qstr qstr;
> > +
> > +	qstr.name = dname;
> > +	qstr.len = strlen(dname);
> > +	qstr.hash = full_name_hash(parent, qstr.name, qstr.len);
> > +
> > +	return d_lookup(parent, &qstr);
> > +}
> > +
> >  static int scmi_telemetry_de_populate(struct super_block *sb,
> >  				      struct scmi_tlm_setup *tsp,
> >  				      struct dentry *parent,
> > @@ -1659,6 +2193,150 @@ static struct dentry *stlmfs_create_root_dentry(struct super_block *sb)
> >  	return dentry;
> >  }
> >  
> > +static int scmi_telemetry_de_subdir_symlink(struct super_block *sb,
> > +					    struct scmi_tlm_setup *tsp,
> > +					    const struct scmi_telemetry_de *de,
> > +					    struct dentry *parent)
> > +{
> > +	struct dentry *dentry;
> > +	struct inode *inode;
> > +	int ret;
> I notice that ret isn't assigned a value and the function returns ret without
> initialising.
>

Yep, my bad: I think it is just a leftover from some last minute cleanup
I have done...it seems to cause only harmless (but noisy) error
messages...thanks for testing...I will fix !

> > +
> > +	if (IS_ERR(parent))
> >  

[snip]

> 
> I will continue reviewing,

Yes please, thanks for having a look.

Thanks,
Cristian