Re: [PATCH v2 3/4] drm: rcar-du: fix DSI enable & disable sequence

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

Hi Tomi,

I love your patch! Perhaps something to improve:

[auto build test WARNING on pinchartl-media/drm/du/next]
[also build test WARNING on linus/master]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Tomi-Valkeinen/drm-rcar-du-DSI-fixes/20220822-210756
base:   git://linuxtv.org/pinchartl/media.git drm/du/next
config: riscv-randconfig-r042-20220821 (https://download.01.org/0day-ci/archive/20220823/202208231031.hFwNDAuL-lkp@intel.com/config)
compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project abce7acebd4c06c977bc4bd79170697f1122bc5e)
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
        # install riscv cross compiling tool for clang build
        # apt-get install binutils-riscv64-linux-gnu
        # https://github.com/intel-lab-lkp/linux/commit/d037472981c443d699c022aa91c5335f686d82ad
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Tomi-Valkeinen/drm-rcar-du-DSI-fixes/20220822-210756
        git checkout d037472981c443d699c022aa91c5335f686d82ad
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash drivers/gpu/drm/rcar-du/

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

All warnings (new ones prefixed by >>):

   In file included from drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c:10:
   In file included from include/linux/io.h:13:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:464:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __raw_readb(PCI_IOBASE + addr);
                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:477:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:36:51: note: expanded from macro '__le16_to_cpu'
   #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
                                                     ^
   In file included from drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c:10:
   In file included from include/linux/io.h:13:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:34:51: note: expanded from macro '__le32_to_cpu'
   #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
                                                     ^
   In file included from drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c:10:
   In file included from include/linux/io.h:13:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writeb(value, PCI_IOBASE + addr);
                               ~~~~~~~~~~ ^
   include/asm-generic/io.h:511:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:521:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:1024:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port;
                                                     ~~~~~~~~~~ ^
>> drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c:615:6: warning: no previous prototype for function 'rcar_mipi_dsi_pclk_enable' [-Wmissing-prototypes]
   void rcar_mipi_dsi_pclk_enable(struct drm_bridge *bridge,
        ^
   drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c:615:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void rcar_mipi_dsi_pclk_enable(struct drm_bridge *bridge,
   ^
   static 
>> drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c:654:6: warning: no previous prototype for function 'rcar_mipi_dsi_pclk_disable' [-Wmissing-prototypes]
   void rcar_mipi_dsi_pclk_disable(struct drm_bridge *bridge)
        ^
   drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c:654:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void rcar_mipi_dsi_pclk_disable(struct drm_bridge *bridge)
   ^
   static 
   9 warnings generated.


vim +/rcar_mipi_dsi_pclk_enable +615 drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c

   614	
 > 615	void rcar_mipi_dsi_pclk_enable(struct drm_bridge *bridge,
   616				       struct drm_atomic_state *state)
   617	{
   618		struct rcar_mipi_dsi *dsi = bridge_to_rcar_mipi_dsi(bridge);
   619		const struct drm_display_mode *mode;
   620		struct drm_connector *connector;
   621		struct drm_crtc *crtc;
   622		int ret;
   623	
   624		connector = drm_atomic_get_new_connector_for_encoder(state,
   625								     bridge->encoder);
   626		crtc = drm_atomic_get_new_connector_state(state, connector)->crtc;
   627		mode = &drm_atomic_get_new_crtc_state(state, crtc)->adjusted_mode;
   628	
   629		ret = rcar_mipi_dsi_clk_enable(dsi);
   630		if (ret < 0) {
   631			dev_err(dsi->dev, "failed to enable DSI clocks\n");
   632			return;
   633		}
   634	
   635		ret = rcar_mipi_dsi_startup(dsi, mode);
   636		if (ret < 0)
   637			goto err_dsi_startup;
   638	
   639		rcar_mipi_dsi_set_display_timing(dsi, mode);
   640	
   641		ret = rcar_mipi_dsi_start_hs_clock(dsi);
   642		if (ret < 0)
   643			goto err_dsi_start_hs;
   644	
   645		return;
   646	
   647	err_dsi_start_hs:
   648		rcar_mipi_dsi_shutdown(dsi);
   649	err_dsi_startup:
   650		rcar_mipi_dsi_clk_disable(dsi);
   651	}
   652	EXPORT_SYMBOL_GPL(rcar_mipi_dsi_pclk_enable);
   653	
 > 654	void rcar_mipi_dsi_pclk_disable(struct drm_bridge *bridge)
   655	{
   656		struct rcar_mipi_dsi *dsi = bridge_to_rcar_mipi_dsi(bridge);
   657	
   658		rcar_mipi_dsi_shutdown(dsi);
   659		rcar_mipi_dsi_clk_disable(dsi);
   660	}
   661	EXPORT_SYMBOL_GPL(rcar_mipi_dsi_pclk_disable);
   662	

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