Hi Sebastian,

I love your patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v5.12 next-20210428]
[cannot apply to robh/for-next shawnguo/for-next abelloni/rtc-next]
[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]

url:    https://github.com/0day-ci/linux/commits/Sebastian-Reichel/Support-for-GE-B1x5v2-and-B1x5Pv2/20210429-063222
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 16b3d0cf5bad844daaf436ad2e9061de0fe36e5c
config: i386-randconfig-s002-20210428 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce:
        # apt-get install sparse
        # sparse version: v0.6.3-341-g8af24329-dirty
        # https://github.com/0day-ci/linux/commit/4d49f1cdc30058ec3d61caa15228353ecb574eef
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Sebastian-Reichel/Support-for-GE-B1x5v2-and-B1x5Pv2/20210429-063222
        git checkout 4d49f1cdc30058ec3d61caa15228353ecb574eef
        # save the attached .config to linux build tree
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' W=1 ARCH=i386 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>


sparse warnings: (new ones prefixed by >>)
>> drivers/rtc/rtc-m41t80.c:560:24: sparse: sparse: Using plain integer as NULL pointer

vim +560 drivers/rtc/rtc-m41t80.c

   542	
   543	static struct clk *m41t80_sqw_register_clk(struct m41t80_data *m41t80)
   544	{
   545		struct i2c_client *client = m41t80->client;
   546		struct device_node *node = client->dev.of_node;
   547		struct device_node *fixed_clock;
   548		struct clk *clk;
   549		struct clk_init_data init;
   550		int ret;
   551	
   552		fixed_clock = of_get_child_by_name(node, "clock");
   553		if (fixed_clock) {
   554			/*
   555			 * skip registering square wave clock when a fixed
   556			 * clock has been registered. The fixed clock is
   557			 * registered automatically when being referenced.
   558			 */
   559			of_node_put(fixed_clock);
 > 560			return 0;
   561		}
   562	
   563		/* First disable the clock */
   564		ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
   565		if (ret < 0)
   566			return ERR_PTR(ret);
   567		ret = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
   568						ret & ~(M41T80_ALMON_SQWE));
   569		if (ret < 0)
   570			return ERR_PTR(ret);
   571	
   572		init.name = "m41t80-sqw";
   573		init.ops = &m41t80_sqw_ops;
   574		init.flags = 0;
   575		init.parent_names = NULL;
   576		init.num_parents = 0;
   577		m41t80->sqw.init = &init;
   578		m41t80->freq = m41t80_get_freq(m41t80);
   579	
   580		/* optional override of the clockname */
   581		of_property_read_string(node, "clock-output-names", &init.name);
   582	
   583		/* register the clock */
   584		clk = clk_register(&client->dev, &m41t80->sqw);
   585		if (!IS_ERR(clk))
   586			of_clk_add_provider(node, of_clk_src_simple_get, clk);
   587	
   588		return clk;
   589	}
   590	#endif
   591	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org