Hi Katsuhiro, I love your patch! Perhaps something to improve:
[auto build test WARNING on linuxtv-media/master] [also build test WARNING on v4.17-rc5 next-20180514] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] url: https://github.com/0day-ci/linux/commits/Katsuhiro-Suzuki/media-dvb-frontends-add-Socionext-SC1501A-ISDB-S-T-demodulator-driver/20180515-091453 base: git://linuxtv.org/media_tree.git master reproduce: # apt-get install sparse make ARCH=x86_64 allmodconfig make C=1 CF=-D__CHECK_ENDIAN__ sparse warnings: (new ones prefixed by >>) >> drivers/media/dvb-frontends/sc1501a.c:313:47: sparse: constant 211243671486 >> is so big it is long vim +313 drivers/media/dvb-frontends/sc1501a.c 258 259 static int sc1501a_s_read_status(struct sc1501a_priv *chip, 260 struct dtv_frontend_properties *c, 261 enum fe_status *status) 262 { 263 struct regmap *r_s = chip->regmap_s; 264 u32 cpmon, tmpu, tmpl, flg; 265 u64 tmp; 266 267 /* Sync detection */ 268 regmap_read(r_s, CPMON1_S, &cpmon); 269 270 *status = 0; 271 if (cpmon & CPMON1_S_FSYNC) 272 *status |= FE_HAS_VITERBI | FE_HAS_SYNC | FE_HAS_LOCK; 273 if (cpmon & CPMON1_S_W2LOCK) 274 *status |= FE_HAS_SIGNAL | FE_HAS_CARRIER; 275 276 /* Signal strength */ 277 c->strength.stat[0].scale = FE_SCALE_NOT_AVAILABLE; 278 279 if (*status & FE_HAS_SIGNAL) { 280 u32 agc; 281 282 regmap_read(r_s, AGCREAD_S, &tmpu); 283 agc = tmpu << 8; 284 285 c->strength.len = 1; 286 c->strength.stat[0].scale = FE_SCALE_RELATIVE; 287 c->strength.stat[0].uvalue = agc; 288 } 289 290 /* C/N rate */ 291 c->cnr.stat[0].scale = FE_SCALE_NOT_AVAILABLE; 292 293 if (*status & FE_HAS_VITERBI) { 294 u32 cnr = 0, x, y, d; 295 u64 d_3 = 0; 296 297 regmap_read(r_s, CNRDXU_S, &tmpu); 298 regmap_read(r_s, CNRDXL_S, &tmpl); 299 x = (tmpu << 8) | tmpl; 300 regmap_read(r_s, CNRDYU_S, &tmpu); 301 regmap_read(r_s, CNRDYL_S, &tmpl); 302 y = (tmpu << 8) | tmpl; 303 304 /* CNR[dB]: 10 * log10(D) - 30.74 / D^3 - 3 */ 305 /* D = x^2 / (2^15 * y - x^2) */ 306 d = (y << 15) - x * x; 307 if (d > 0) { 308 /* (2^4 * D)^3 = 2^12 * D^3 */ 309 /* 3.074 * 2^(12 + 24) = 211243671486 */ 310 d_3 = div_u64(16 * x * x, d); 311 d_3 = d_3 * d_3 * d_3; 312 if (d_3) > 313 d_3 = div_u64(211243671486, d_3); 314 } 315 316 if (d_3) { 317 /* 0.3 * 2^24 = 5033164 */ 318 tmp = (s64)2 * intlog10(x) - intlog10(abs(d)) - d_3 319 - 5033164; 320 cnr = div_u64(tmp * 10000, 1 << 24); 321 } 322 323 if (cnr) { 324 c->cnr.len = 1; 325 c->cnr.stat[0].scale = FE_SCALE_DECIBEL; 326 c->cnr.stat[0].uvalue = cnr; 327 } 328 } 329 330 /* BER */ 331 c->post_bit_error.stat[0].scale = FE_SCALE_NOT_AVAILABLE; 332 c->post_bit_count.stat[0].scale = FE_SCALE_NOT_AVAILABLE; 333 334 regmap_read(r_s, BERCNFLG_S, &flg); 335 336 if ((*status & FE_HAS_VITERBI) && (flg & BERCNFLG_S_BERVRDY)) { 337 u32 bit_err, bit_cnt; 338 339 regmap_read(r_s, BERVRDU_S, &tmpu); 340 regmap_read(r_s, BERVRDL_S, &tmpl); 341 bit_err = (tmpu << 8) | tmpl; 342 bit_cnt = (1 << 13) * 204; 343 344 if (bit_cnt) { 345 c->post_bit_error.len = 1; 346 c->post_bit_error.stat[0].scale = FE_SCALE_COUNTER; 347 c->post_bit_error.stat[0].uvalue = bit_err; 348 c->post_bit_count.len = 1; 349 c->post_bit_count.stat[0].scale = FE_SCALE_COUNTER; 350 c->post_bit_count.stat[0].uvalue = bit_cnt; 351 } 352 } 353 354 return 0; 355 } 356 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
