Re: [PATCH v3 1/1] i2c: imc-skylake: add Intel Skylake-X iMC SMBus adapter

Hi Simone,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 8cd9520d35a6c38db6567e97dd93b1f11f185dc6]

url:    https://github.com/intel-lab-lkp/linux/commits/Simone-Chifari/i2c-imc-skylake-add-Intel-Skylake-X-iMC-SMBus-adapter/20260729-033603
base:   8cd9520d35a6c38db6567e97dd93b1f11f185dc6
patch link:    https://lore.kernel.org/r/20260728122423.358416-2-simone.chifari%40gmail.com
patch subject: [PATCH v3 1/1] i2c: imc-skylake: add Intel Skylake-X iMC SMBus adapter
config: um-randconfig-r133-20260729 (https://download.01.org/0day-ci/archive/20260729/[email protected]/config)
compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
sparse: v0.6.5-rc1
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260729/[email protected]/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 <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/

All warnings (new ones prefixed by >>):

   In file included from drivers/i2c/busses/i2c-imc-skylake.c:49:
   In file included from include/linux/i2c.h:19:
   In file included from include/linux/regulator/consumer.h:35:
   In file included from include/linux/suspend.h:5:
   In file included from include/linux/swap.h:9:
   In file included from include/linux/memcontrol.h:13:
   In file included from include/linux/cgroup.h:27:
   In file included from include/linux/kernel_stat.h:8:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:24:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:12:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:1209:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
    1209 |         return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port;
         |                                                   ~~~~~~~~~~ ^
>> drivers/i2c/busses/i2c-imc-skylake.c:331:28: warning: implicit conversion from 'unsigned long' to 'u32' (aka 'unsigned int') changes value from 18446744073171697664 to 3757113344 [-Wconstant-conversion]
     331 |                 u32 mask = i == c->idx ? ~COMMAND_OUR_BITS : ~0U;
         |                     ~~~~                 ^~~~~~~~~~~~~~~~~
   2 warnings generated.


vim +331 drivers/i2c/busses/i2c-imc-skylake.c

   317	
   318	/*
   319	 * Detect a second master.  Compare the command registers against what this
   320	 * driver left in them: for the channel it drove, only the bits it does not own;
   321	 * for the other channel, all of them.  A difference means firmware, a BMC or
   322	 * CLTT touched the engine while the transfer was in flight, so the result
   323	 * cannot be trusted.
   324	 */
   325	static int imc_check_interference(struct imc_smbus *s, const struct imc_chan *c,
   326					  const struct imc_xfer_state *state)
   327	{
   328		int i;
   329	
   330		for (i = 0; i < ARRAY_SIZE(imc_chans); i++) {
 > 331			u32 mask = i == c->idx ? ~COMMAND_OUR_BITS : ~0U;
   332			u32 expect = state->command[i] & COMMAND_KEEP_MASK;
   333			u32 now = imc_reg(s, imc_chans[i].data);
   334	
   335			if (!((now ^ expect) & mask))
   336				continue;
   337	
   338			dev_warn_ratelimited(s->dev,
   339					     "ch%d command changed under us (0x%08x -> 0x%08x): another master is using the engine\n",
   340					     i, expect, now);
   341			return -EAGAIN;
   342		}
   343	
   344		return 0;
   345	}
   346	

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