drivers/iio/temperature/ltc2983.c:549:29: warning: 'strcmp' of a string of length 24 and an array of size 22 evaluates to nonzero

drivers/iio/temperature/ltc2983.c:549:29: warning: 'strcmp' of a string of length 24 and an array of size 22 evaluates to nonzero

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   827751b699b79a6e569983359c02dce67f81b94c
commit: 3dd0c048409e335320418c632966f149be628fd4 iio: temperature: ltc2983: Add support for ADT7604
date:   3 months ago
config: s390-randconfig-r052-20260911 (https://download.01.org/0day-ci/archive/20260912/202609120045.OxEsKLIn-lkp@intel.com/config)
compiler: s390-linux-gcc (GCC) 10.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260912/202609120045.OxEsKLIn-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
| Fixes: 3dd0c048409e ("iio: temperature: ltc2983: Add support for ADT7604")
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202609120045.OxEsKLIn-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In function '__ltc2983_custom_sensor_new',
       inlined from 'ltc2983_thermistor_new' at drivers/iio/temperature/ltc2983.c:1069:24:
>> drivers/iio/temperature/ltc2983.c:549:29: warning: 'strcmp' of a string of length 24 and an array of size 22 evaluates to nonzero [-Wstring-compare]
     549 |    if ((index % 2) != 0 && !strcmp(propname, "adi,custom-leak-detector"))
         |                             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +/strcmp +549 drivers/iio/temperature/ltc2983.c

   472	
   473	static struct ltc2983_custom_sensor *
   474	__ltc2983_custom_sensor_new(struct ltc2983_data *st, const struct fwnode_handle *fn,
   475				    const char *propname, const bool is_steinhart,
   476				    const u32 resolution, const bool has_signed)
   477	{
   478		struct ltc2983_custom_sensor *new_custom;
   479		struct device *dev = &st->spi->dev;
   480		/*
   481		 * For custom steinhart, the full u32 is taken. For all the others
   482		 * the MSB is discarded.
   483		 */
   484		const u8 n_size = is_steinhart ? 4 : 3;
   485		u8 index, n_entries;
   486		int ret;
   487	
   488		if (is_steinhart)
   489			n_entries = fwnode_property_count_u32(fn, propname);
   490		else
   491			n_entries = fwnode_property_count_u64(fn, propname);
   492		/* n_entries must be an even number */
   493		if (!n_entries || (n_entries % 2) != 0)
   494			return dev_err_ptr_probe(dev, -EINVAL,
   495						 "Number of entries either 0 or not even\n");
   496	
   497		new_custom = devm_kzalloc(dev, sizeof(*new_custom), GFP_KERNEL);
   498		if (!new_custom)
   499			return ERR_PTR(-ENOMEM);
   500	
   501		new_custom->size = n_entries * n_size;
   502		/* check Steinhart size */
   503		if (is_steinhart && new_custom->size != LTC2983_CUSTOM_STEINHART_SIZE)
   504			return dev_err_ptr_probe(dev, -EINVAL,
   505						 "Steinhart sensors size(%zu) must be %u\n",
   506						 new_custom->size, LTC2983_CUSTOM_STEINHART_SIZE);
   507	
   508		/* Check space on the table. */
   509		if (st->custom_table_size + new_custom->size >
   510		    (LTC2983_CUST_SENS_TBL_END_REG - LTC2983_CUST_SENS_TBL_START_REG) + 1)
   511			return dev_err_ptr_probe(dev, -EINVAL,
   512						 "No space left(%d) for new custom sensor(%zu)\n",
   513						 st->custom_table_size, new_custom->size);
   514	
   515		/* allocate the table */
   516		if (is_steinhart)
   517			new_custom->table = devm_kcalloc(dev, n_entries, sizeof(u32), GFP_KERNEL);
   518		else
   519			new_custom->table = devm_kcalloc(dev, n_entries, sizeof(u64), GFP_KERNEL);
   520		if (!new_custom->table)
   521			return ERR_PTR(-ENOMEM);
   522	
   523		/*
   524		 * Steinhart sensors are configured with raw values in the firmware
   525		 * node. For the other sensors we must convert the value to raw.
   526		 * The odd index's correspond to temperatures and always have 1/1024
   527		 * of resolution. Temperatures also come in Kelvin, so signed values
   528		 * are not possible.
   529		 */
   530		if (is_steinhart) {
   531			ret = fwnode_property_read_u32_array(fn, propname, new_custom->table, n_entries);
   532			if (ret < 0)
   533				return ERR_PTR(ret);
   534	
   535			cpu_to_be32_array(new_custom->table, new_custom->table, n_entries);
   536		} else {
   537			ret = fwnode_property_read_u64_array(fn, propname, new_custom->table, n_entries);
   538			if (ret < 0)
   539				return ERR_PTR(ret);
   540	
   541			for (index = 0; index < n_entries; index++) {
   542				u64 temp = ((u64 *)new_custom->table)[index];
   543	
   544				/*
   545				 * Users specify plain coverage percentage (0-100). Convert
   546				 * to µK so __convert_to_raw() produces the correct hardware
   547				 * encoding: P + 273.15 K.
   548				 */
 > 549				if ((index % 2) != 0 && !strcmp(propname, "adi,custom-leak-detector"))
   550					temp = temp * 1000000 + 273150000;
   551	
   552				if ((index % 2) != 0)
   553					temp = __convert_to_raw(temp, 1024);
   554				else if (has_signed && (s64)temp < 0)
   555					temp = __convert_to_raw_sign(temp, resolution);
   556				else
   557					temp = __convert_to_raw(temp, resolution);
   558	
   559				put_unaligned_be24(temp, new_custom->table + index * 3);
   560			}
   561		}
   562	
   563		new_custom->is_steinhart = is_steinhart;
   564		/*
   565		 * This is done to first add all the steinhart sensors to the table,
   566		 * in order to maximize the table usage. If we mix adding steinhart
   567		 * with the other sensors, we might have to do some roundup to make
   568		 * sure that sensor_addr - 0x250(start address) is a multiple of 4
   569		 * (for steinhart), and a multiple of 6 for all the other sensors.
   570		 * Since we have const 24 bytes for steinhart sensors and 24 is
   571		 * also a multiple of 6, we guarantee that the first non-steinhart
   572		 * sensor will sit in a correct address without the need of filling
   573		 * addresses.
   574		 */
   575		if (is_steinhart) {
   576			new_custom->offset = st->custom_table_size /
   577						LTC2983_CUSTOM_STEINHART_ENTRY_SZ;
   578			st->custom_table_size += new_custom->size;
   579		} else {
   580			/* mark as unset. This is checked later on the assign phase */
   581			new_custom->offset = -1;
   582		}
   583	
   584		return new_custom;
   585	}
   586	

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