Hi Alexandru,

I love your patch! Perhaps something to improve:

[auto build test WARNING on iio/togreg]
[also build test WARNING on linux/master next-20210125]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Alexandru-Ardelean/iio-core-buffer-add-support-for-multiple-IIO-buffers-per-IIO-device/20210201-233550
base:   https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git togreg
config: openrisc-randconfig-p001-20210201 (attached as .config)
compiler: or1k-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/418ff389a5a48a8a515a106734474e98d6d924ad
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Alexandru-Ardelean/iio-core-buffer-add-support-for-multiple-IIO-buffers-per-IIO-device/20210201-233550
        git checkout 418ff389a5a48a8a515a106734474e98d6d924ad
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=openrisc 

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

All warnings (new ones prefixed by >>):

>> drivers/iio/industrialio-buffer.c:1306:6: warning: no previous prototype for 'iio_buffer_unregister_legacy_sysfs_groups' [-Wmissing-prototypes]
    1306 | void iio_buffer_unregister_legacy_sysfs_groups(struct iio_dev *indio_dev)
         |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/iio/industrialio-buffer.c:1178:27: warning: 'iio_scan_elements_group_name' defined but not used [-Wunused-const-variable=]
    1178 | static const char * const iio_scan_elements_group_name = "scan_elements";
         |                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +/iio_buffer_unregister_legacy_sysfs_groups +1306 drivers/iio/industrialio-buffer.c

  1305	
> 1306	void iio_buffer_unregister_legacy_sysfs_groups(struct iio_dev *indio_dev)
  1307	{
  1308		struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
  1309	
  1310		kfree(iio_dev_opaque->legacy_buffer_group.attrs);
  1311		kfree(iio_dev_opaque->legacy_scan_el_group.attrs);
  1312	}
  1313	

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