[PATCH net 1/4] auxiliary: Allow empty id

Sean Anderson sean.anderson at linux.dev
Thu Jun 19 13:05:34 PDT 2025


Support creating auxiliary devices with the id included as part of the
name. This allows for non-decimal ids, which may be more appropriate for
auxiliary devices created as children of memory-mapped devices. For
example, a name like "xilinx_emac.mac.802c0000" could be achieved by
setting .name to "mac.802c0000" and .id to AUXILIARY_DEVID_NONE.

Signed-off-by: Sean Anderson <sean.anderson at linux.dev>
---

 drivers/base/auxiliary.c      | 6 +++++-
 include/linux/auxiliary_bus.h | 4 +++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/base/auxiliary.c b/drivers/base/auxiliary.c
index dba7c8e13a53..64a0d5e2eb83 100644
--- a/drivers/base/auxiliary.c
+++ b/drivers/base/auxiliary.c
@@ -331,7 +331,11 @@ int __auxiliary_device_add(struct auxiliary_device *auxdev, const char *modname)
 		return -EINVAL;
 	}
 
-	ret = dev_set_name(dev, "%s.%s.%d", modname, auxdev->name, auxdev->id);
+	if (auxdev->id == AUXILIARY_DEVID_NONE)
+		ret = dev_set_name(dev, "%s.%s", modname, auxdev->name);
+	else
+		ret = dev_set_name(dev, "%s.%s.%d", modname, auxdev->name,
+				   auxdev->id);
 	if (ret) {
 		dev_err(dev, "auxiliary device dev_set_name failed: %d\n", ret);
 		return ret;
diff --git a/include/linux/auxiliary_bus.h b/include/linux/auxiliary_bus.h
index 4086afd0cc6b..76904cf2c3dd 100644
--- a/include/linux/auxiliary_bus.h
+++ b/include/linux/auxiliary_bus.h
@@ -51,6 +51,8 @@
  * unregisters the auxiliary device.
  */
 
+#define AUXILIARY_DEVID_NONE	(-1)
+
 /**
  * struct auxiliary_device - auxiliary device object.
  * @dev: Device,
@@ -269,7 +271,7 @@ struct auxiliary_device *__devm_auxiliary_device_create(struct device *dev,
 
 #define devm_auxiliary_device_create(dev, devname, platform_data)     \
 	__devm_auxiliary_device_create(dev, KBUILD_MODNAME, devname,  \
-				       platform_data, 0)
+				       platform_data, AUXILIARY_DEVID_NONE)
 
 /**
  * module_auxiliary_driver() - Helper macro for registering an auxiliary driver
-- 
2.35.1.1320.gc452695387.dirty




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