[PATCH v2] media: ipu3-cio2: support multiple sensors and VCMs with HID name

[PATCH v2] media: ipu3-cio2: support multiple sensors and VCMs with HID name

[bingbu.cao]

From: Bingbu Cao <bingbu.cao@intel.com>

In current cio2-bridge, it is using the hid name to register software
node and software node will create kobject and sysfs entry according to
the node name, if there are multiple sensors and VCMs which are sharing
same HID name, it will cause the software nodes registration failure:

sysfs: cannot create duplicate filename '/kernel/software_nodes/dw9714'
...
Call Trace:
sysfs_create_dir_ns+0xbc/0xd0
kobject_add_internal
kobject_init_and_add
swnode_register
software_node_register
software_node_register_nodes
cio2_bridge_init
...
kobject_add_internal failed for dw9714 with -EEXIST,
don't try to register things with the same name in the same directory.

One solution is appending the sensor link(Mipi Port) in SSDB as suffix
of the node name to fix this problem.

Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
---
Changes from v1:
 - Use snprintf() instead of scnprinf()
 - Add comments to explain why expand the name size
 - Remove the distracting information of backtraces in commit message
---
 drivers/media/pci/intel/ipu3/cio2-bridge.c | 15 +++++++++++----
 drivers/media/pci/intel/ipu3/cio2-bridge.h |  3 ++-
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/media/pci/intel/ipu3/cio2-bridge.c b/drivers/media/pci/intel/ipu3/cio2-bridge.c
index dfefe0d8aa95..45427a3a3a25 100644
--- a/drivers/media/pci/intel/ipu3/cio2-bridge.c
+++ b/drivers/media/pci/intel/ipu3/cio2-bridge.c
@@ -212,6 +212,7 @@ static void cio2_bridge_create_connection_swnodes(struct cio2_bridge *bridge,
 						  struct cio2_sensor *sensor)
 {
 	struct software_node *nodes = sensor->swnodes;
+	char vcm_name[ACPI_ID_LEN + 4];
 
 	cio2_bridge_init_swnode_names(sensor);
 
@@ -229,9 +230,13 @@ static void cio2_bridge_create_connection_swnodes(struct cio2_bridge *bridge,
 						sensor->node_names.endpoint,
 						&nodes[SWNODE_CIO2_PORT],
 						sensor->cio2_properties);
-	if (sensor->ssdb.vcmtype)
-		nodes[SWNODE_VCM] =
-			NODE_VCM(cio2_vcm_types[sensor->ssdb.vcmtype - 1]);
+	if (sensor->ssdb.vcmtype) {
+		/* append ssdb.link to distinguish VCM nodes with same HID */
+		snprintf(vcm_name, sizeof(vcm_name), "%s-%u",
+			 cio2_vcm_types[sensor->ssdb.vcmtype - 1],
+			 sensor->ssdb.link);
+		nodes[SWNODE_VCM] = NODE_VCM(vcm_name);
+	}
 
 	cio2_bridge_init_swnode_group(sensor);
 }
@@ -295,7 +300,6 @@ static int cio2_bridge_connect_sensor(const struct cio2_sensor_config *cfg,
 		}
 
 		sensor = &bridge->sensors[bridge->n_sensors];
-		strscpy(sensor->name, cfg->hid, sizeof(sensor->name));
 
 		ret = cio2_bridge_read_acpi_buffer(adev, "SSDB",
 						   &sensor->ssdb,
@@ -303,6 +307,9 @@ static int cio2_bridge_connect_sensor(const struct cio2_sensor_config *cfg,
 		if (ret)
 			goto err_put_adev;
 
+		snprintf(sensor->name, sizeof(sensor->name), "%s-%u",
+			 cfg->hid, sensor->ssdb.link);
+
 		if (sensor->ssdb.vcmtype > ARRAY_SIZE(cio2_vcm_types)) {
 			dev_warn(&adev->dev, "Unknown VCM type %d\n",
 				 sensor->ssdb.vcmtype);
diff --git a/drivers/media/pci/intel/ipu3/cio2-bridge.h b/drivers/media/pci/intel/ipu3/cio2-bridge.h
index b93b749c65bd..b76ed8a641e2 100644
--- a/drivers/media/pci/intel/ipu3/cio2-bridge.h
+++ b/drivers/media/pci/intel/ipu3/cio2-bridge.h
@@ -113,7 +113,8 @@ struct cio2_sensor_config {
 };
 
 struct cio2_sensor {
-	char name[ACPI_ID_LEN];
+	/* append ssdb.link(u8) in "-%u" format as suffix of HID */
+	char name[ACPI_ID_LEN + 4];
 	struct acpi_device *adev;
 	struct i2c_client *vcm_i2c_client;
 
-- 
2.39.1

Re: [PATCH v2] media: ipu3-cio2: support multiple sensors and VCMs with HID name

[Andy Shevchenko]

On Tue, Mar 07, 2023 at 02:31:10PM +0800, bingbu.cao@intel.com wrote:
> From: Bingbu Cao <bingbu.cao@intel.com>
> 
> In current cio2-bridge, it is using the hid name to register software
> node and software node will create kobject and sysfs entry according to
> the node name, if there are multiple sensors and VCMs which are sharing
> same HID name, it will cause the software nodes registration failure:
> 
> sysfs: cannot create duplicate filename '/kernel/software_nodes/dw9714'
> ...

> Call Trace:
> sysfs_create_dir_ns+0xbc/0xd0
> kobject_add_internal
> kobject_init_and_add
> swnode_register
> software_node_register

The above lines are not so valuable. You can remove them.

> software_node_register_nodes
> cio2_bridge_init
> ...
> kobject_add_internal failed for dw9714 with -EEXIST,
> don't try to register things with the same name in the same directory.
> 
> One solution is appending the sensor link(Mipi Port) in SSDB as suffix
> of the node name to fix this problem.

-- 
With Best Regards,
Andy Shevchenko