Hi,

kernel test robot noticed the following build errors:

[auto build test ERROR on lee-mfd/for-mfd-next]
[also build test ERROR on brgl/gpio/for-next andi-shyti/i2c/i2c-host mkl-can-next/testing groeck-staging/hwmon-next abelloni/rtc-next linus/master lee-mfd/for-mfd-fixes v6.15-rc5 next-20250507]
[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/a0282524688-gmail-com/mfd-Add-core-driver-for-Nuvoton-NCT6694/20250423-174637
base:   https://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd.git for-mfd-next
patch link:    https://lore.kernel.org/r/20250423094058.1656204-5-tmyu0%40nuvoton.com
patch subject: [PATCH v10 4/7] can: Add Nuvoton NCT6694 CANFD support
config: hexagon-allmodconfig (https://download.01.org/0day-ci/archive/20250507/202505072336.mhh6H9Ma-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/20250507/202505072336.mhh6H9Ma-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 [off-list ref]
| Closes: https://lore.kernel.org/oe-kbuild-all/202505072336.mhh6H9Ma-lkp@intel.com/ (local)

All errors (new ones prefixed by >>):

quoted

drivers/net/can/usb/nct6694_canfd.c:543:30: error: call to undeclared function 'FIELD_PREP'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]

     543 |         setting->nbtp = cpu_to_le32(FIELD_PREP(NCT6694_CANFD_SETTING_NBTP_NSJW,
         |                                     ^
   include/linux/byteorder/generic.h:88:21: note: expanded from macro 'cpu_to_le32'
      88 | #define cpu_to_le32 __cpu_to_le32
         |                     ^
   1 error generated.


vim +/FIELD_PREP +543 drivers/net/can/usb/nct6694_canfd.c

   512	
   513	static int nct6694_canfd_start(struct net_device *ndev)
   514	{
   515		struct nct6694_canfd_priv *priv = netdev_priv(ndev);
   516		const struct can_bittiming *d_bt = &priv->can.data_bittiming;
   517		const struct can_bittiming *n_bt = &priv->can.bittiming;
   518		struct nct6694_canfd_setting *setting __free(kfree) = NULL;
   519		const struct nct6694_cmd_header cmd_hd = {
   520			.mod = NCT6694_CANFD_MOD,
   521			.cmd = NCT6694_CANFD_SETTING,
   522			.sel = ndev->dev_port,
   523			.len = cpu_to_le16(sizeof(*setting))
   524		};
   525		int ret;
   526	
   527		setting = kzalloc(sizeof(*setting), GFP_KERNEL);
   528		if (!setting)
   529			return -ENOMEM;
   530	
   531		if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
   532			setting->ctrl1 |= cpu_to_le16(NCT6694_CANFD_SETTING_CTRL1_MON);
   533	
   534		if (priv->can.ctrlmode & CAN_CTRLMODE_FD_NON_ISO)
   535			setting->ctrl1 |= cpu_to_le16(NCT6694_CANFD_SETTING_CTRL1_NISO);
   536	
   537		if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
   538			setting->ctrl1 |= cpu_to_le16(NCT6694_CANFD_SETTING_CTRL1_LBCK);
   539	
   540		/* Disable clock divider */
   541		setting->ctrl2 = 0;
   542	
 > 543		setting->nbtp = cpu_to_le32(FIELD_PREP(NCT6694_CANFD_SETTING_NBTP_NSJW,
   544						       n_bt->sjw - 1) |
   545					    FIELD_PREP(NCT6694_CANFD_SETTING_NBTP_NBRP,
   546						       n_bt->brp - 1) |
   547					    FIELD_PREP(NCT6694_CANFD_SETTING_NBTP_NTSEG2,
   548						       n_bt->phase_seg2 - 1) |
   549					    FIELD_PREP(NCT6694_CANFD_SETTING_NBTP_NTSEG1,
   550						       n_bt->prop_seg + n_bt->phase_seg1 - 1));
   551	
   552		setting->dbtp = cpu_to_le32(FIELD_PREP(NCT6694_CANFD_SETTING_DBTP_DSJW,
   553						       d_bt->sjw - 1) |
   554					    FIELD_PREP(NCT6694_CANFD_SETTING_DBTP_DBRP,
   555						       d_bt->brp - 1) |
   556					    FIELD_PREP(NCT6694_CANFD_SETTING_DBTP_DTSEG2,
   557						       d_bt->phase_seg2 - 1) |
   558					    FIELD_PREP(NCT6694_CANFD_SETTING_DBTP_DTSEG1,
   559						       d_bt->prop_seg + d_bt->phase_seg1 - 1));
   560	
   561		setting->active = NCT6694_CANFD_SETTING_ACTIVE_CTRL1 |
   562				  NCT6694_CANFD_SETTING_ACTIVE_CTRL2 |
   563				  NCT6694_CANFD_SETTING_ACTIVE_NBTP_DBTP;
   564	
   565		ret = nct6694_write_msg(priv->nct6694, &cmd_hd, setting);
   566		if (ret)
   567			return ret;
   568	
   569		priv->can.state = CAN_STATE_ERROR_ACTIVE;
   570	
   571		return 0;
   572	}
   573	

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