Hi Fabrizio,

I love your patch! Perhaps something to improve:

[auto build test WARNING on char-misc/char-misc-testing]
[also build test WARNING on robh/for-next renesas-drivers/renesas-clk renesas-devel/next v5.11 next-20210226]
[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/Fabrizio-Castro/Add-FFT-Support-for-R-Car-Gen3-devices/20210226-065737
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git 29c395c77a9a514c5857c45ceae2665e9bd99ac7
config: arm64-allyesconfig (attached as .config)
compiler: aarch64-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/7f7ea7f057fde0d61b09f379dbd6abec9d00f713
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Fabrizio-Castro/Add-FFT-Support-for-R-Car-Gen3-devices/20210226-065737
        git checkout 7f7ea7f057fde0d61b09f379dbd6abec9d00f713
        # 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: kernel test robot <redacted>

All warnings (new ones prefixed by >>):

quoted

drivers/misc/rcar_dab/rcar_dev.c:20:13: warning: no previous prototype for 'rcar_dab_irq' [-Wmissing-prototypes]

      20 | irqreturn_t rcar_dab_irq(int irq, void *devid)
         |             ^~~~~~~~~~~~


vim +/rcar_dab_irq +20 drivers/misc/rcar_dab/rcar_dev.c

    19	
  > 20	irqreturn_t rcar_dab_irq(int irq, void *devid)
    21	{
    22		struct rcar_dab *dab = devid;
    23		u32 intsr, intcr1;
    24	
    25		spin_lock(&dab->shared_regs_lock);
    26	
    27		intcr1 = rcar_dab_read(dab, RCAR_DAB_INTCR1);
    28		rcar_dab_write(dab, RCAR_DAB_INTCR1, 0x000003FF);
    29	
    30		intsr = rcar_dab_read(dab, RCAR_DAB_INTSR);
    31		if (!intsr) {
    32			rcar_dab_write(dab, RCAR_DAB_INTCR1, intcr1);
    33			spin_unlock(&dab->shared_regs_lock);
    34			return IRQ_NONE;
    35		}
    36	
    37		/* Re-enable interrupts that haven't fired */
    38		rcar_dab_write(dab, RCAR_DAB_INTCR1, 0x3FF & (intsr | intcr1));
    39		/* Clear interrupts */
    40		rcar_dab_write(dab, RCAR_DAB_INTSR, 0x7 & ~intsr);
    41	
    42		spin_unlock(&dab->shared_regs_lock);
    43	
    44		if (intsr & RCAR_DAB_INTSR_FFT_DONE)
    45			rcar_dab_fft_irq(dab);
    46	
    47		return IRQ_HANDLED;
    48	}
    49	

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