Re: [PATCH v5 06/10] clk: Add Sunplus SP7021 clock driver

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

Hi Qin,

I love your patch! Perhaps something to improve:

[auto build test WARNING on clk/clk-next]
[also build test WARNING on tip/irq/core linus/master v5.16-rc3 next-20211203]
[cannot apply to pza/reset/next robh/for-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/Qin-Jian/Add-Sunplus-SP7021-SoC-Support/20211203-154345
base:   https://git.kernel.org/pub/scm/linux/kernel/git/clk/linux.git clk-next
config: arc-allyesconfig (https://download.01.org/0day-ci/archive/20211203/202112032353.vXXsrZu2-lkp@intel.com/config)
compiler: arceb-elf-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/ebecbb4f178661a7de3c03b73ccd59722c3ee26c
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Qin-Jian/Add-Sunplus-SP7021-SoC-Support/20211203-154345
        git checkout ebecbb4f178661a7de3c03b73ccd59722c3ee26c
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=arc SHELL=/bin/bash drivers/clk/ drivers/irqchip/

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

All warnings (new ones prefixed by >>):

   drivers/clk/clk-sp7021.c: In function 'plltv_fractional_div':
>> drivers/clk/clk-sp7021.c:304:13: warning: variable 'diff_min_sign' set but not used [-Wunused-but-set-variable]
     304 |         u32 diff_min_sign = 0;
         |             ^~~~~~~~~~~~~
   drivers/clk/clk-sp7021.c: At top level:
>> drivers/clk/clk-sp7021.c:638:13: warning: no previous prototype for 'clk_register_sp_pll' [-Wmissing-prototypes]
     638 | struct clk *clk_register_sp_pll(const char *name, const char *parent,
         |             ^~~~~~~~~~~~~~~~~~~


vim +/diff_min_sign +304 drivers/clk/clk-sp7021.c

   298	
   299	static long plltv_fractional_div(struct sp_pll *clk, unsigned long freq)
   300	{
   301		u32 m, r;
   302		u32 nint, nfra;
   303		u32 diff_min_quotient = 210000000, diff_min_remainder = 0;
 > 304		u32 diff_min_sign = 0;
   305		unsigned long fvco, nf, f, fout = 0;
   306		int sdm, ph;
   307	
   308		/* check freq */
   309		if (freq < F_MIN) {
   310			pr_warn("%s: %s freq:%lu < F_MIN:%lu, round up\n",
   311				__func__, clk_hw_get_name(&clk->hw), freq, F_MIN);
   312			freq = F_MIN;
   313		} else if (freq > F_MAX) {
   314			pr_warn("%s: %s freq:%lu > F_MAX:%lu, round down\n",
   315				__func__, clk_hw_get_name(&clk->hw), freq, F_MAX);
   316			freq = F_MAX;
   317		}
   318	
   319		/* DIVR 0~3 */
   320		for (r = 0; r <= 3; r++) {
   321			fvco = freq << r;
   322			if (fvco <= FVCO_MAX)
   323				break;
   324		}
   325		f = F_27M >> r;
   326	
   327		/* PH_SEL 1/0 */
   328		for (ph = 1; ph >= 0; ph--) {
   329			const u32 *pp = pt[ph];
   330			u32 ms = 1;
   331	
   332			/* SDM_MOD 0/1 */
   333			for (sdm = 0; sdm <= 1; sdm++) {
   334				u32 mod = mods[sdm];
   335	
   336				/* DIVM 1~32 */
   337				for (m = ms; m <= 32; m++) {
   338					u32 diff_freq;
   339					u32 diff_freq_quotient = 0, diff_freq_remainder = 0;
   340					u32 diff_freq_sign = 0; /* 0:Positive number, 1:Negative number */
   341	
   342					nf = fvco * m;
   343					nint = nf / pp[3];
   344	
   345					if (nint < pp[1])
   346						continue;
   347					if (nint > pp[1])
   348						break;
   349	
   350					nfra = (((nf % pp[3]) * mod * pp[4]) + (F_27M / 2)) / F_27M;
   351					if (nfra)
   352						diff_freq = (f * (nint + pp[2]) / pp[0]) -
   353									(f * (mod - nfra) / mod / pp[4]);
   354					else
   355						diff_freq = (f * (nint) / pp[0]);
   356	
   357					diff_freq_quotient  = diff_freq / m;
   358					diff_freq_remainder = ((diff_freq % m) * 1000) / m;
   359	
   360					if (freq > diff_freq_quotient) {
   361						diff_freq_quotient  = freq - diff_freq_quotient - 1;
   362						diff_freq_remainder = 1000 - diff_freq_remainder;
   363						diff_freq_sign = 1;
   364					} else {
   365						diff_freq_quotient = diff_freq_quotient - freq;
   366						diff_freq_sign = 0;
   367					}
   368	
   369					if (diff_min_quotient > diff_freq_quotient ||
   370					    (diff_min_quotient == diff_freq_quotient &&
   371					    diff_min_remainder > diff_freq_remainder)) {
   372						/* found a closer freq, save parameters */
   373						clk->p[SEL_FRA] = 1;
   374						clk->p[SDM_MOD] = sdm;
   375						clk->p[PH_SEL]  = ph;
   376						clk->p[NFRA]    = nfra;
   377						clk->p[DIVR]    = r;
   378						clk->p[DIVM]    = m;
   379	
   380						fout = diff_freq / m;
   381						diff_min_quotient = diff_freq_quotient;
   382						diff_min_remainder = diff_freq_remainder;
   383						diff_min_sign = diff_freq_sign;
   384					}
   385				}
   386			}
   387		}
   388	
   389		if (!fout) {
   390			pr_err("%s: %s freq:%lu not found a valid setting\n",
   391			       __func__, clk_hw_get_name(&clk->hw), freq);
   392			return -EINVAL;
   393		}
   394	
   395		return fout;
   396	}
   397	

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

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