[PATCH v6 2/3] drm/bridge: imx: Add i.MX93 parallel display format configuration support

[kernel test robot]

Hi Marco,

kernel test robot noticed the following build errors:

[auto build test ERROR on 3a8660878839faadb4f1a6dd72c3179c1df56787]

url:    https://github.com/intel-lab-lkp/linux/commits/Marco-Felsch/dt-bindings-soc-imx93-media-blk-ctrl-Add-PDFC-subnode-to-schema-and-example/20251202-011707
base:   3a8660878839faadb4f1a6dd72c3179c1df56787
patch link:    https://lore.kernel.org/r/20251201-v6-18-topic-imx93-parallel-display-v6-2-7b056e1e5b1e%40pengutronix.de
patch subject: [PATCH v6 2/3] drm/bridge: imx: Add i.MX93 parallel display format configuration support
config: hexagon-allmodconfig (https://download.01.org/0day-ci/archive/20251202/202512021733.cIbkorvY-lkp@intel.com/config)
compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251202/202512021733.cIbkorvY-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 at intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202512021733.cIbkorvY-lkp@intel.com/

All errors (new ones prefixed by >>):

>> drivers/gpu/drm/bridge/imx/imx93-pdfc.c:55:9: error: call to undeclared function 'FIELD_PREP'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
      55 |                 val = FORMAT_RGB888_TO_RGB888;
         |                       ^
   drivers/gpu/drm/bridge/imx/imx93-pdfc.c:21:34: note: expanded from macro 'FORMAT_RGB888_TO_RGB888'
      21 | #define FORMAT_RGB888_TO_RGB888         FIELD_PREP(PARALLEL_DISP_FORMAT, 0)
         |                                         ^
   1 error generated.


vim +/FIELD_PREP +55 drivers/gpu/drm/bridge/imx/imx93-pdfc.c

    42	
    43	static void imx93_pdfc_bridge_atomic_enable(struct drm_bridge *bridge,
    44						    struct drm_atomic_state *state)
    45	{
    46		struct imx93_pdfc *pdfc = bridge->driver_private;
    47		const struct drm_bridge_state *bridge_state;
    48		unsigned int mask = PARALLEL_DISP_FORMAT;
    49		unsigned int val;
    50	
    51		bridge_state = drm_atomic_get_new_bridge_state(state, bridge);
    52	
    53		switch (bridge_state->output_bus_cfg.format) {
    54		case MEDIA_BUS_FMT_RGB888_1X24:
  > 55			val = FORMAT_RGB888_TO_RGB888;
    56			if (pdfc->phy_bus_width == 18) {
    57				/*
    58				 * Can be valid if physical bus limitation exist,
    59				 * therefore use dev_dbg().
    60				 */
    61				dev_dbg(pdfc->dev, "Truncate two LSBs from each color\n");
    62				val = FORMAT_RGB888_TO_RGB666;
    63			}
    64			break;
    65		case MEDIA_BUS_FMT_RGB666_1X18:
    66			val = FORMAT_RGB888_TO_RGB666;
    67			break;
    68		case MEDIA_BUS_FMT_RGB565_1X16:
    69			val = FORMAT_RGB565_TO_RGB565;
    70			break;
    71		}
    72	
    73		regmap_update_bits(pdfc->regmap, pdfc->disp_mux_reg_off, mask, val);
    74	}
    75	

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https://github.com/intel/lkp-tests/wiki