Re: [PATCH 3/5] iio: mcp9600: Recognize chip id for mcp9601

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

Hi Ben,

kernel test robot noticed the following build warnings:

[auto build test WARNING on jic23-iio/togreg]
[also build test WARNING on linus/master v6.17-rc1 next-20250815]
[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/Ben-Collins/dt-bindings-iio-mcp9600-Add-compatible-for-microchip-mcp9601/20250816-005705
base:   https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git togreg
patch link:    https://lore.kernel.org/r/20250815164627.22002-4-bcollins%40watter.com
patch subject: [PATCH 3/5] iio: mcp9600: Recognize chip id for mcp9601
config: riscv-randconfig-001-20250816 (https://download.01.org/0day-ci/archive/20250816/202508161646.PDl6V4EU-lkp@intel.com/config)
compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project 93d24b6b7b148c47a2fa228a4ef31524fa1d9f3f)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250816/202508161646.PDl6V4EU-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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202508161646.PDl6V4EU-lkp@intel.com/

All warnings (new ones prefixed by >>):

   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/riscv/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:12:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:820:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     820 |         insl(addr, buffer, count);
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:106:53: note: expanded from macro 'insl'
     106 | #define insl(addr, buffer, count) __insl(PCI_IOBASE + (addr), buffer, count)
         |                                          ~~~~~~~~~~ ^
   In file included from drivers/iio/temperature/mcp9600.c:13:
   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/riscv/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:12:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:829:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     829 |         outsb(addr, buffer, count);
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:118:55: note: expanded from macro 'outsb'
     118 | #define outsb(addr, buffer, count) __outsb(PCI_IOBASE + (addr), buffer, count)
         |                                            ~~~~~~~~~~ ^
   In file included from drivers/iio/temperature/mcp9600.c:13:
   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/riscv/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:12:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:838:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     838 |         outsw(addr, buffer, count);
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:119:55: note: expanded from macro 'outsw'
     119 | #define outsw(addr, buffer, count) __outsw(PCI_IOBASE + (addr), buffer, count)
         |                                            ~~~~~~~~~~ ^
   In file included from drivers/iio/temperature/mcp9600.c:13:
   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/riscv/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:12:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:847:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     847 |         outsl(addr, buffer, count);
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/riscv/include/asm/io.h:120:55: note: expanded from macro 'outsl'
     120 | #define outsl(addr, buffer, count) __outsl(PCI_IOBASE + (addr), buffer, count)
         |                                            ~~~~~~~~~~ ^
   In file included from drivers/iio/temperature/mcp9600.c:13:
   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/riscv/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:12:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:1175:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
    1175 |         return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port;
         |                                                   ~~~~~~~~~~ ^
>> drivers/iio/temperature/mcp9600.c:440:53: warning: invalid conversion specifier '\x0a' [-Wformat-invalid-specifier]
     440 |                                 "Expected id %02x, but device responded with %02\n",
         |                                                                              ~~~^
   include/linux/dev_printk.h:156:62: note: expanded from macro 'dev_warn'
     156 |         dev_printk_index_wrap(_dev_warn, KERN_WARNING, dev, dev_fmt(fmt), ##__VA_ARGS__)
         |                                                                     ^~~
   include/linux/dev_printk.h:19:22: note: expanded from macro 'dev_fmt'
      19 | #define dev_fmt(fmt) fmt
         |                      ^~~
   include/linux/dev_printk.h:110:16: note: expanded from macro 'dev_printk_index_wrap'
     110 |                 _p_func(dev, fmt, ##__VA_ARGS__);                       \
         |                              ^~~
>> drivers/iio/temperature/mcp9600.c:441:26: warning: data argument not used by format string [-Wformat-extra-args]
     440 |                                 "Expected id %02x, but device responded with %02\n",
         |                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     441 |                                  chip_info->chip_id, dev_id);
         |                                                      ^
   include/linux/dev_printk.h:156:70: note: expanded from macro 'dev_warn'
     156 |         dev_printk_index_wrap(_dev_warn, KERN_WARNING, dev, dev_fmt(fmt), ##__VA_ARGS__)
         |                                                                     ~~~     ^
   include/linux/dev_printk.h:110:23: note: expanded from macro 'dev_printk_index_wrap'
     110 |                 _p_func(dev, fmt, ##__VA_ARGS__);                       \
         |                              ~~~    ^
   drivers/iio/temperature/mcp9600.c:428:22: warning: unused variable 'ret' [-Wunused-variable]
     428 |         int ch_sel, dev_id, ret;
         |                             ^~~
   10 warnings generated.


vim +/x0a +440 drivers/iio/temperature/mcp9600.c

   422	
   423	static int mcp9600_probe(struct i2c_client *client)
   424	{
   425		const struct mcp_chip_info *chip_info = i2c_get_match_data(client);
   426		struct iio_dev *indio_dev;
   427		struct mcp9600_data *data;
   428		int ch_sel, dev_id, ret;
   429	
   430		dev_id = i2c_smbus_read_byte_data(client, MCP9600_DEVICE_ID);
   431		if (dev_id < 0)
   432			return dev_err_probe(&client->dev, dev_id,
   433					     "Failed to read device ID\n");
   434	
   435		switch (dev_id) {
   436		case MCP9600_DEVICE_ID_MCP9600:
   437		case MCP9600_DEVICE_ID_MCP9601:
   438			if (dev_id != chip_info->chip_id)
   439				dev_warn(&client->dev,
 > 440					"Expected id %02x, but device responded with %02\n",
 > 441					 chip_info->chip_id, dev_id);
   442			break;
   443	
   444		default:
   445			dev_warn(&client->dev, "Unknown id %x, using %x\n", dev_id,
   446				 chip_info->chip_id);
   447		}
   448	
   449		indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
   450		if (!indio_dev)
   451			return -ENOMEM;
   452	
   453		data = iio_priv(indio_dev);
   454		data->client = client;
   455	
   456		ch_sel = mcp9600_probe_alerts(indio_dev);
   457		if (ch_sel < 0)
   458			return ch_sel;
   459	
   460		indio_dev->info = &mcp9600_info;
   461		indio_dev->name = chip_info->chip_name;
   462		indio_dev->modes = INDIO_DIRECT_MODE;
   463		indio_dev->channels = mcp9600_channels[ch_sel];
   464		indio_dev->num_channels = ARRAY_SIZE(mcp9600_channels[ch_sel]);
   465	
   466		return devm_iio_device_register(&client->dev, indio_dev);
   467	}
   468	

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