[chrome-os:chromeos-6.6 354/354] drivers/gpu/drm/mediatek/mtk_dvo.c:808:14: warning: no previous prototype for 'mtk_dvo_encoder_index'

[kernel test robot <lkp@intel.com>]

tree:   https://chromium.googlesource.com/chromiumos/third_party/kernel chromeos-6.6
head:   db867ccf596a910b85bab8c6052afe59fa921727
commit: 67be6bf2abc721aedffdc60f176b59c6374f712d [354/354] CHROMIUM: drm/mediatek: mt8189: mmsys driver probe
config: arm-randconfig-002-20250813 (https://download.01.org/0day-ci/archive/20250813/202508131900.E41zdAa0-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 8.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250813/202508131900.E41zdAa0-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202508131900.E41zdAa0-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/gpu/drm/mediatek/mtk_dvo.c:275:6: warning: no previous prototype for 'mtk_dvo_mutex_vsync_set' [-Wmissing-prototypes]
    void mtk_dvo_mutex_vsync_set(struct mtk_dvo *dvo)
         ^~~~~~~~~~~~~~~~~~~~~~~
   drivers/gpu/drm/mediatek/mtk_dvo.c: In function 'mtk_dvo_sodi_setting':
   drivers/gpu/drm/mediatek/mtk_dvo.c:302:6: warning: variable 'data_rate' set but not used [-Wunused-but-set-variable]
     u64 data_rate = 0;
         ^~~~~~~~~
   drivers/gpu/drm/mediatek/mtk_dvo.c: At top level:
   drivers/gpu/drm/mediatek/mtk_dvo.c:781:6: warning: no previous prototype for 'mtk_dvo_start' [-Wmissing-prototypes]
    void mtk_dvo_start(struct device *dev)
         ^~~~~~~~~~~~~
   drivers/gpu/drm/mediatek/mtk_dvo.c:788:6: warning: no previous prototype for 'mtk_dvo_stop' [-Wmissing-prototypes]
    void mtk_dvo_stop(struct device *dev)
         ^~~~~~~~~~~~
   drivers/gpu/drm/mediatek/mtk_dvo.c:795:6: warning: no previous prototype for 'mtk_dvo_get_hrt_bw_by_datarate' [-Wmissing-prototypes]
    void mtk_dvo_get_hrt_bw_by_datarate(struct device *dev, unsigned int *bw_base)
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> drivers/gpu/drm/mediatek/mtk_dvo.c:808:14: warning: no previous prototype for 'mtk_dvo_encoder_index' [-Wmissing-prototypes]
    unsigned int mtk_dvo_encoder_index(struct device *dev)
                 ^~~~~~~~~~~~~~~~~~~~~


vim +/mtk_dvo_encoder_index +808 drivers/gpu/drm/mediatek/mtk_dvo.c

   780	
 > 781	void mtk_dvo_start(struct device *dev)
   782	{
   783		struct mtk_dvo *dvo = dev_get_drvdata(dev);
   784	
   785		mtk_dvo_power_on(dvo);
   786	}
   787	
   788	void mtk_dvo_stop(struct device *dev)
   789	{
   790		struct mtk_dvo *dvo = dev_get_drvdata(dev);
   791	
   792		mtk_dvo_power_off(dvo);
   793	}
   794	
   795	void mtk_dvo_get_hrt_bw_by_datarate(struct device *dev, unsigned int *bw_base)
   796	{
   797		struct mtk_dvo *dvo = dev_get_drvdata(dev);
   798		int htotal, vtotal, vrefresh;
   799	
   800		htotal = dvo->mode.htotal;
   801		vtotal = dvo->mode.vtotal;
   802		vrefresh = drm_mode_vrefresh(&dvo->mode);
   803	
   804		*bw_base = (unsigned int)div_u64((unsigned long long)vtotal * htotal * vrefresh * 4,
   805						 1000000);
   806	}
   807	
 > 808	unsigned int mtk_dvo_encoder_index(struct device *dev)
   809	{
   810		struct mtk_dvo *dvo = dev_get_drvdata(dev);
   811		unsigned int encoder_index = drm_encoder_index(&dvo->encoder);
   812	
   813		dev_dbg(dev, "encoder index:%d\n", encoder_index);
   814		return encoder_index;
   815	}
   816	

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