drivers/hwmon/gpd-fan.c:231:9: error: implicit declaration of function 'outb'

From: kernel test robot

Date: Thu Oct 23 2025 - 20:06:14 EST


Hi Cryolitia,

FYI, the error/warning still remains.

tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 266ee584e55eed108583ab4f45b5de734522502d
commit: 0ab88e2394392f475b8857ac82c0c987841217f8 hwmon: add GPD devices sensor driver
date: 6 weeks ago
config: i386-buildonly-randconfig-002-20251024 (https://download.01.org/0day-ci/archive/20251024/202510240817.vt3eQ3qL-lkp@xxxxxxxxx/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251024/202510240817.vt3eQ3qL-lkp@xxxxxxxxx/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@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202510240817.vt3eQ3qL-lkp@xxxxxxxxx/

All errors (new ones prefixed by >>):

drivers/hwmon/gpd-fan.c: In function 'gpd_ecram_read':
>> drivers/hwmon/gpd-fan.c:231:9: error: implicit declaration of function 'outb' [-Wimplicit-function-declaration]
231 | outb(0x2E, addr_port);
| ^~~~
>> drivers/hwmon/gpd-fan.c:244:16: error: implicit declaration of function 'inb' [-Wimplicit-function-declaration]
244 | *val = inb(data_port);
| ^~~


vim +/outb +231 drivers/hwmon/gpd-fan.c

224
225 // Helper functions to handle EC read/write
226 static void gpd_ecram_read(u16 offset, u8 *val)
227 {
228 u16 addr_port = gpd_driver_priv.drvdata->addr_port;
229 u16 data_port = gpd_driver_priv.drvdata->data_port;
230
> 231 outb(0x2E, addr_port);
232 outb(0x11, data_port);
233 outb(0x2F, addr_port);
234 outb((u8)((offset >> 8) & 0xFF), data_port);
235
236 outb(0x2E, addr_port);
237 outb(0x10, data_port);
238 outb(0x2F, addr_port);
239 outb((u8)(offset & 0xFF), data_port);
240
241 outb(0x2E, addr_port);
242 outb(0x12, data_port);
243 outb(0x2F, addr_port);
> 244 *val = inb(data_port);
245 }
246

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