Hi Dave,

It's probably a bug fix that unveils the link errors.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   642b151f45dd54809ea00ecd3976a56c1ec9b53d
commit: 7ebdc26a315ac0f13369eaf922bcee3ede576438 Merge tag 'drm-misc-next-fixes-2020-02-07' of git://anongit.freedesktop.org/drm/drm-misc into drm-fixes
date:   3 months ago
config: arm64-randconfig-r024-20200518 (attached as .config)
compiler: aarch64-linux-gcc (GCC) 9.3.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        git checkout 7ebdc26a315ac0f13369eaf922bcee3ede576438
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arm64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kbuild test robot <lkp@intel.com>

All errors (new ones prefixed by >>, old ones prefixed by <<):

aarch64-linux-ld: drivers/iio/accel/bma400_i2c.o: in function `bma400_i2c_probe':
>> drivers/iio/accel/bma400_i2c.c:21: undefined reference to `__devm_regmap_init_i2c'

vim +21 drivers/iio/accel/bma400_i2c.c

465c811f1f201a Dan Robertson 2019-12-20  15  
465c811f1f201a Dan Robertson 2019-12-20  16  static int bma400_i2c_probe(struct i2c_client *client,
465c811f1f201a Dan Robertson 2019-12-20  17  			    const struct i2c_device_id *id)
465c811f1f201a Dan Robertson 2019-12-20  18  {
465c811f1f201a Dan Robertson 2019-12-20  19  	struct regmap *regmap;
465c811f1f201a Dan Robertson 2019-12-20  20  
465c811f1f201a Dan Robertson 2019-12-20 @21  	regmap = devm_regmap_init_i2c(client, &bma400_regmap_config);
465c811f1f201a Dan Robertson 2019-12-20  22  	if (IS_ERR(regmap)) {
465c811f1f201a Dan Robertson 2019-12-20  23  		dev_err(&client->dev, "failed to create regmap\n");
465c811f1f201a Dan Robertson 2019-12-20  24  		return PTR_ERR(regmap);
465c811f1f201a Dan Robertson 2019-12-20  25  	}
465c811f1f201a Dan Robertson 2019-12-20  26  
465c811f1f201a Dan Robertson 2019-12-20  27  	return bma400_probe(&client->dev, regmap, id->name);
465c811f1f201a Dan Robertson 2019-12-20  28  }
465c811f1f201a Dan Robertson 2019-12-20  29  

:::::: The code at line 21 was first introduced by commit
:::::: 465c811f1f201a7554a95cf003bc06a239606e9b iio: accel: Add driver for the BMA400

:::::: TO: Dan Robertson <dan@dlrobertson.com>
:::::: CC: Jonathan Cameron <Jonathan.Cameron@huawei.com>

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org