编译5.15.59内核蓝牙驱动模块时遇__regmap_init未定义错误求助

API 探路者

2026-7-22

问题

为NAS设备编译USB蓝牙驱动内核模块（内核版本5.15.59），net/bluetooth模块可通过以下命令正常编译：

make M=net/bluetooth

但编译drivers/bluetooth/btintel.ko时出现错误：

ERROR: modpost: "__regmap_init" [drivers/bluetooth/btintel.ko] undefined!

尝试使用以下命令编译仍失败：

make KBUILD_EXTRA_SYMBOLS=net/bluetooth/Module.symvers M=drivers/bluetooth

相关.config配置片段：

CONFIG_BT=m
CONFIG_BT_BREDR=y
CONFIG_BT_RFCOMM=m
CONFIG_BT_RFCOMM_TTY=y
CONFIG_BT_BNEP=m
CONFIG_BT_BNEP_MC_FILTER=y
CONFIG_BT_BNEP_PROTO_FILTER=y
CONFIG_BT_HIDP=m
# CONFIG_BT_HS is not set
# CONFIG_BT_LE is not set
# CONFIG_BT_MSFTEXT is not set
# CONFIG_BT_AOSPEXT is not set
# CONFIG_BT_DEBUGFS is not set
# CONFIG_BT_SELFTEST is not set
# CONFIG_BT_FEATURE_DEBUG is not set

#
# Bluetooth device drivers
#
CONFIG_BT_INTEL=m
CONFIG_BT_RTL=m
CONFIG_BT_HCIBTUSB=m
# CONFIG_BT_HCIBTUSB_AUTOSUSPEND is not set
# CONFIG_BT_HCIBTUSB_BCM is not set
# CONFIG_BT_HCIBTUSB_MTK is not set
CONFIG_BT_HCIBTUSB_RTL=y
CONFIG_BT_HCIUART=m
CONFIG_BT_HCIUART_H4=y
CONFIG_BT_HCIUART_BCSP=y
CONFIG_BT_HCIUART_ATH3K=y
# CONFIG_BT_HCIUART_AG6XX is not set
# CONFIG_BT_HCIBCM203X is not set
# CONFIG_BT_HCIBPA10X is not set
# CONFIG_BT_HCIBFUSB is not set
# CONFIG_BT_HCIDTL1 is not set
# CONFIG_BT_HCIBT3C is not set
# CONFIG_BT_HCIBLUECARD is not set
CONFIG_BT_HCIVHCI=m
# CONFIG_BT_MRVL is not set
# CONFIG_BT_ATH3K is not set
# end of Bluetooth device drivers

解决方案

__regmap_init符号来自内核的regmap框架模块，当前.config未开启相关配置，导致编译btintel时找不到该符号。

修改内核.config文件，添加或开启以下配置：
```
CONFIG_REGMAP=m
```
也可直接将CONFIG_REGMAP设为y（编译进内核而非模块），若蓝牙设备涉及I2C通信，可额外开启CONFIG_REGMAP_I2C=m。
重新编译时，可选择以下方式：
- 先编译regmap模块，再编译btintel：
```
make M=drivers/base/regmap
make M=drivers/bluetooth
```
- 或者通过KBUILD_EXTRA_SYMBOLS指定regmap的符号文件路径：
```
make KBUILD_EXTRA_SYMBOLS=drivers/base/regmap/Module.symvers M=drivers/bluetooth
```

完成以上操作后，btintel.ko即可正常编译，所需的__regmap_init符号将由regmap模块提供。

内容的提问来源于stack exchange，提问作者outkastm