Hi Sebastian,

I love your patch! Perhaps something to improve:

[auto build test WARNING on robh/for-next]
[also build test WARNING on char-misc/char-misc-testing v5.13-rc3]
[cannot apply to spi/for-next next-20210528]
[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/Sebastian-Reichel/GE-Healthcare-PPD-firmware-upgrade-driver-for-ACHC/20210528-193816
base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next
config: nds32-randconfig-p002-20210528 (attached as .config)
compiler: nds32le-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/dac014da90e2715a80e4f7139ac40333cd3d4bec
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Sebastian-Reichel/GE-Healthcare-PPD-firmware-upgrade-driver-for-ACHC/20210528-193816
        git checkout dac014da90e2715a80e4f7139ac40333cd3d4bec
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=nds32 

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/spi/spidev.c:730:5: warning: no previous prototype for 'spidev_probe' [-Wmissing-prototypes]
     730 | int spidev_probe(struct spi_device *spi)
         |     ^~~~~~~~~~~~
>> drivers/spi/spidev.c:793:5: warning: no previous prototype for 'spidev_remove' [-Wmissing-prototypes]
     793 | int spidev_remove(struct spi_device *spi)
         |     ^~~~~~~~~~~~~


vim +/spidev_probe +730 drivers/spi/spidev.c

   729	
 > 730	int spidev_probe(struct spi_device *spi)
   731	{
   732		struct spidev_data	*spidev;
   733		int			status;
   734		unsigned long		minor;
   735	
   736		/*
   737		 * spidev should never be referenced in DT without a specific
   738		 * compatible string, it is a Linux implementation thing
   739		 * rather than a description of the hardware.
   740		 */
   741		WARN(spi->dev.of_node &&
   742		     of_device_is_compatible(spi->dev.of_node, "spidev"),
   743		     "%pOF: buggy DT: spidev listed directly in DT\n", spi->dev.of_node);
   744	
   745		spidev_probe_acpi(spi);
   746	
   747		/* Allocate driver data */
   748		spidev = kzalloc(sizeof(*spidev), GFP_KERNEL);
   749		if (!spidev)
   750			return -ENOMEM;
   751	
   752		/* Initialize the driver data */
   753		spidev->spi = spi;
   754		spin_lock_init(&spidev->spi_lock);
   755		mutex_init(&spidev->buf_lock);
   756	
   757		INIT_LIST_HEAD(&spidev->device_entry);
   758	
   759		/* If we can allocate a minor number, hook up this device.
   760		 * Reusing minors is fine so long as udev or mdev is working.
   761		 */
   762		mutex_lock(&device_list_lock);
   763		minor = find_first_zero_bit(minors, N_SPI_MINORS);
   764		if (minor < N_SPI_MINORS) {
   765			struct device *dev;
   766	
   767			spidev->devt = MKDEV(SPIDEV_MAJOR, minor);
   768			dev = device_create(spidev_class, &spi->dev, spidev->devt,
   769					    spidev, "spidev%d.%d",
   770					    spi->master->bus_num, spi->chip_select);
   771			status = PTR_ERR_OR_ZERO(dev);
   772		} else {
   773			dev_dbg(&spi->dev, "no minor number available!\n");
   774			status = -ENODEV;
   775		}
   776		if (status == 0) {
   777			set_bit(minor, minors);
   778			list_add(&spidev->device_entry, &device_list);
   779		}
   780		mutex_unlock(&device_list_lock);
   781	
   782		spidev->speed_hz = spi->max_speed_hz;
   783	
   784		if (status == 0)
   785			spi_set_drvdata(spi, spidev);
   786		else
   787			kfree(spidev);
   788	
   789		return status;
   790	}
   791	EXPORT_SYMBOL_GPL(spidev_probe);
   792	
 > 793	int spidev_remove(struct spi_device *spi)
   794	{
   795		struct spidev_data	*spidev = spi_get_drvdata(spi);
   796	
   797		/* prevent new opens */
   798		mutex_lock(&device_list_lock);
   799		/* make sure ops on existing fds can abort cleanly */
   800		spin_lock_irq(&spidev->spi_lock);
   801		spidev->spi = NULL;
   802		spin_unlock_irq(&spidev->spi_lock);
   803	
   804		list_del(&spidev->device_entry);
   805		device_destroy(spidev_class, spidev->devt);
   806		clear_bit(MINOR(spidev->devt), minors);
   807		if (spidev->users == 0)
   808			kfree(spidev);
   809		mutex_unlock(&device_list_lock);
   810	
   811		return 0;
   812	}
   813	EXPORT_SYMBOL_GPL(spidev_remove);
   814	

---
0-DAY CI Kernel Test Service, Intel Corporation
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