Hi Adam,

[FYI, it's a private test report for your RFC patch.]
[auto build test WARNING on clk/clk-next]
[also build test WARNING on v5.11-rc2 next-20210104]
[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/Adam-Ford/dt-bindings-clk-versaclock5-Add-load-capacitance-properties/20210107-014404
base:   https://git.kernel.org/pub/scm/linux/kernel/git/clk/linux.git clk-next
config: x86_64-randconfig-m001-20210106 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0

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

New smatch warnings:
drivers/clk/clk-versaclock5.c:803 vc5_update_cap_load() warn: unsigned 'mapped_value' is never less than zero.

Old smatch warnings:
drivers/clk/clk-versaclock5.c:811 vc5_update_cap_load() warn: unsigned 'mapped_value' is never less than zero.

vim +/mapped_value +803 drivers/clk/clk-versaclock5.c

   761	
   762	static int vc5_map_cap_value(u32 femtofarads)
   763	{
   764		int mapped_value;
   765	
   766		/* The datasheet explicitly states 9000 - 25000 */
   767		if ((femtofarads < 9000) || (femtofarads > 25000))
   768			return -EINVAL;
   769	
   770		/* The lowest target we can hit is 9430, so exit if it's less */
   771		if (femtofarads < 9430)
   772			return 0;
   773	
   774		/*
   775		 * According to VersaClock 6E Programming Guide, there are 6
   776		 * bits which translate to 64 entries in XTAL registers 12 and
   777		 * 13. Because bits 0 and 1 increase the capacitance the
   778		 * same, some of the values can be repeated.  Plugging this
   779		 * into a spreadsheet and generating a trendline, the output
   780		 * equation becomes x = (y-9098.29) / 216.44, where 'y' is
   781		 * the desired capacitance in femtofarads, and x is the value
   782		 * of XTAL[5:0].
   783		 * To help with rounding, do fixed point math
   784		 */
   785		femtofarads *= 100;
   786		mapped_value = (femtofarads - 909829) / 21644;
   787	
   788		/*
   789		 * The datasheet states, the maximum capacitance is 25000,
   790		 * but the programmer guide shows a max value is 22832,
   791		 * so values higher values could overflow, so cap it.
   792		 */
   793		mapped_value = max(mapped_value/100, 0x3f);
   794	
   795		return mapped_value;
   796	}
   797	static int vc5_update_cap_load(struct device_node *node, struct vc5_driver_data *vc5)
   798	{
   799		u32 value, mapped_value;
   800	
   801		if (!of_property_read_u32(node, "idt,xtal1-load-femtofarads", &value)) {
   802			mapped_value = vc5_map_cap_value(value);
 > 803			if (mapped_value < 0)
   804				return mapped_value;
   805	
   806			regmap_write(vc5->regmap, VC5_XTAL_X1_LOAD_CAP, (mapped_value << 2));
   807		}
   808	
   809		if (!of_property_read_u32(node, "idt,xtal2-load-femtofarads", &value)) {
   810			mapped_value = vc5_map_cap_value(value);
   811			if (mapped_value < 0)
   812				return mapped_value;
   813			regmap_write(vc5->regmap, VC5_XTAL_X2_LOAD_CAP, (mapped_value << 2));
   814		}
   815	
   816		return 0;
   817	}
   818	

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