Re: [PATCH v4 06/10] clk: Add Sunplus SP7021 clock driver

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

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Hi Qin,

I love your patch! Perhaps something to improve:

[auto build test WARNING on pza/reset/next]
[also build test WARNING on robh/for-next clk/clk-next tip/irq/core linus/master v5.15 next-20211104]
[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/dt-bindings-vendor-prefixes-Add-Sunplus/20211104-115746
base:   https://git.pengutronix.de/git/pza/linux reset/next
config: xtensa-randconfig-r012-20211104 (attached as .config)
compiler: xtensa-linux-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/604141a9aad536dff720a6337561171d72d63d74
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Qin-Jian/dt-bindings-vendor-prefixes-Add-Sunplus/20211104-115746
        git checkout 604141a9aad536dff720a6337561171d72d63d74
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=xtensa 

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:292:13: warning: variable 'diff_min_sign' set but not used [-Wunused-but-set-variable]
     292 |         u32 diff_min_sign = 0;
         |             ^~~~~~~~~~~~~
   drivers/clk/clk-sp7021.c: At top level:
   drivers/clk/clk-sp7021.c:625:13: warning: no previous prototype for 'clk_register_sp_pll' [-Wmissing-prototypes]
     625 | struct clk *clk_register_sp_pll(const char *name, const char *parent,
         |             ^~~~~~~~~~~~~~~~~~~


vim +/diff_min_sign +292 drivers/clk/clk-sp7021.c

   286	
   287	static long plltv_fractional_div(struct sp_pll *clk, unsigned long freq)
   288	{
   289		u32 m, r;
   290		u32 nint, nfra;
   291		u32 diff_min_quotient = 210000000, diff_min_remainder = 0;
 > 292		u32 diff_min_sign = 0;
   293		unsigned long fvco, nf, f, fout = 0;
   294		int sdm, ph;
   295	
   296		/* check freq */
   297		if (freq < F_MIN) {
   298			pr_warn("%s: %s freq:%lu < F_MIN:%lu, round up\n",
   299				__func__, clk_hw_get_name(&clk->hw), freq, F_MIN);
   300			freq = F_MIN;
   301		} else if (freq > F_MAX) {
   302			pr_warn("%s: %s freq:%lu > F_MAX:%lu, round down\n",
   303				__func__, clk_hw_get_name(&clk->hw), freq, F_MAX);
   304			freq = F_MAX;
   305		}
   306	
   307		/* DIVR 0~3 */
   308		for (r = 0; r <= 3; r++) {
   309			fvco = freq << r;
   310			if (fvco <= FVCO_MAX)
   311				break;
   312		}
   313		f = F_27M >> r;
   314	
   315		/* PH_SEL 1/0 */
   316		for (ph = 1; ph >= 0; ph--) {
   317			const u32 *pp = pt[ph];
   318			u32 ms = 1;
   319	
   320			/* SDM_MOD 0/1 */
   321			for (sdm = 0; sdm <= 1; sdm++) {
   322				u32 mod = mods[sdm];
   323	
   324				/* DIVM 1~32 */
   325				for (m = ms; m <= 32; m++) {
   326					u32 diff_freq;
   327					u32 diff_freq_quotient = 0, diff_freq_remainder = 0;
   328					u32 diff_freq_sign = 0; /* 0:Positive number, 1:Negative number */
   329	
   330					nf = fvco * m;
   331					nint = nf / pp[3];
   332	
   333					if (nint < pp[1])
   334						continue;
   335					if (nint > pp[1])
   336						break;
   337	
   338					nfra = (((nf % pp[3]) * mod * pp[4]) + (F_27M / 2)) / F_27M;
   339					if (nfra)
   340						diff_freq = (f * (nint + pp[2]) / pp[0]) -
   341									(f * (mod - nfra) / mod / pp[4]);
   342					else
   343						diff_freq = (f * (nint) / pp[0]);
   344	
   345					diff_freq_quotient  = diff_freq / m;
   346					diff_freq_remainder = ((diff_freq % m) * 1000) / m;
   347	
   348					if (freq > diff_freq_quotient) {
   349						diff_freq_quotient  = freq - diff_freq_quotient - 1;
   350						diff_freq_remainder = 1000 - diff_freq_remainder;
   351						diff_freq_sign = 1;
   352					} else {
   353						diff_freq_quotient = diff_freq_quotient - freq;
   354						diff_freq_sign = 0;
   355					}
   356	
   357					if ((diff_min_quotient > diff_freq_quotient) ||
   358						((diff_min_quotient == diff_freq_quotient) &&
   359						(diff_min_remainder > diff_freq_remainder))) {
   360	
   361						/* found a closer freq, save parameters */
   362						clk->p[SEL_FRA] = 1;
   363						clk->p[SDM_MOD] = sdm;
   364						clk->p[PH_SEL]  = ph;
   365						clk->p[NFRA]    = nfra;
   366						clk->p[DIVR]    = r;
   367						clk->p[DIVM]    = m;
   368	
   369						fout = diff_freq / m;
   370						diff_min_quotient = diff_freq_quotient;
   371						diff_min_remainder = diff_freq_remainder;
   372						diff_min_sign = diff_freq_sign;
   373					}
   374				}
   375			}
   376		}
   377	
   378		if (!fout) {
   379			pr_err("%s: %s freq:%lu not found a valid setting\n",
   380				__func__, clk_hw_get_name(&clk->hw), freq);
   381			return -EINVAL;
   382		}
   383	
   384		return fout;
   385	}
   386	

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

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