Hi Manikandan, kernel test robot noticed the following build warnings: [auto build test WARNING on robh/for-next] [also build test WARNING on drm-misc/drm-misc-next linus/master v6.11-rc3 next-20240816] [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#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Manikandan-Muralidharan/dt-bindings-display-bridge-add-sam9x75-mipi-dsi-binding/20240814-234923 base: https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next patch link: https://lore.kernel.org/r/20240814105256.177319-3-manikandan.m%40microchip.com patch subject: [PATCH v3 2/4] drm/bridge: add Microchip DSI controller support for sam9x7 SoC series config: arm-randconfig-r071-20240816 (https://download.01.org/0day-ci/archive/20240816/202408162158.TlOqyoUA-lkp@xxxxxxxxx/config) compiler: clang version 15.0.7 (https://github.com/llvm/llvm-project 8dfdcc7b7bf66834a761bd8de445840ef68e4d1a) 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 | Reported-by: kernel test robot <lkp@xxxxxxxxx> | Closes: https://lore.kernel.org/oe-kbuild-all/202408162158.TlOqyoUA-lkp@xxxxxxxxx/ smatch warnings: drivers/gpu/drm/bridge/dw-mipi-dsi-mchp.c:293 dw_mipi_dsi_mchp_get_lane_mbps() warn: unsigned 'bpp' is never less than zero. drivers/gpu/drm/bridge/dw-mipi-dsi-mchp.c:293 dw_mipi_dsi_mchp_get_lane_mbps() warn: error code type promoted to positive: 'bpp' drivers/gpu/drm/bridge/dw-mipi-dsi-mchp.c:314 dw_mipi_dsi_mchp_get_lane_mbps() error: uninitialized symbol 'target_mbps'. vim +/bpp +293 drivers/gpu/drm/bridge/dw-mipi-dsi-mchp.c 276 277 static int dw_mipi_dsi_mchp_get_lane_mbps(void *priv_data, 278 const struct drm_display_mode *mode, 279 unsigned long mode_flags, u32 lanes, 280 u32 format, unsigned int *lane_mbps) 281 { 282 struct dw_mipi_dsi_mchp *dsi = priv_data; 283 unsigned long best_freq, fvco_min, fvco_max, fin, fout; 284 unsigned long min_delta = ULONG_MAX, delta; 285 unsigned int mpclk, target_mbps, desired_mbps; 286 unsigned int max_mbps = dppa_map[ARRAY_SIZE(dppa_map) - 1].max_mbps; 287 unsigned int bpp, min_prediv, max_prediv; 288 unsigned int _fbdiv, best_fbdiv, _prediv, best_prediv; 289 u64 freq_factor; 290 291 dsi->format = format; 292 bpp = mipi_dsi_pixel_format_to_bpp(dsi->format); > 293 if (bpp < 0) { 294 dev_err(dsi->dev, 295 "failed to get bpp for pixel format %d\n", 296 dsi->format); 297 return bpp; 298 } 299 300 mpclk = DIV_ROUND_UP(mode->clock, MSEC_PER_SEC); 301 if (mpclk) { 302 /* take 1/0.8, since mbps must be bigger than bandwidth of RGB */ 303 desired_mbps = mpclk * (bpp / lanes) * 10 / 8; 304 if (desired_mbps < max_mbps) { 305 target_mbps = desired_mbps; 306 } else { 307 dev_err(dsi->dev, 308 "DPHY clock frequency is out of range\n"); 309 return -ERANGE; 310 } 311 } 312 313 fin = clk_get_rate(dsi->pllref_clk); > 314 fout = target_mbps * USEC_PER_SEC; 315 316 /* constraint: 5Mhz <= Fref / N <= 40MHz */ 317 min_prediv = DIV_ROUND_UP(fin, 40 * USEC_PER_SEC); 318 max_prediv = fin / (5 * USEC_PER_SEC); 319 320 /* constraint: 80MHz <= Fvco <= 1000Mhz */ 321 fvco_min = 80 * USEC_PER_SEC; 322 fvco_max = 1000 * USEC_PER_SEC; 323 324 for (best_freq = 0, _prediv = min_prediv; _prediv <= max_prediv; _prediv++) { 325 /* Fvco = Fref * M / N */ 326 freq_factor = fout * _prediv; 327 do_div(freq_factor, fin); 328 _fbdiv = freq_factor; 329 /* 330 * Due to the use of a "by 2 pre-scaler," the range of the 331 * feedback multiplication value M is limited to even division 332 * numbers, and m must be greater than 6, not bigger than 512. 333 */ 334 if (_fbdiv < 6 || _fbdiv > 512) 335 continue; 336 337 _fbdiv += _fbdiv % 2; 338 339 freq_factor = _fbdiv * fin; 340 do_div(freq_factor, _prediv); 341 if (freq_factor < fvco_min || freq_factor > fvco_max) 342 continue; 343 344 delta = abs(fout - freq_factor); 345 if (delta < min_delta) { 346 best_prediv = _prediv; 347 best_fbdiv = _fbdiv; 348 min_delta = delta; 349 best_freq = freq_factor; 350 } 351 } 352 353 if (best_freq) { 354 dsi->lane_mbps = DIV_ROUND_UP(best_freq, USEC_PER_SEC); 355 *lane_mbps = dsi->lane_mbps; 356 dsi->input_div = best_prediv; 357 dsi->feedback_div = best_fbdiv; 358 } else { 359 dev_err(dsi->dev, "Can not find best_freq for DPHY\n"); 360 return -EINVAL; 361 } 362 363 return 0; 364 } 365 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
