Hi Stefan, I love your patch! Perhaps something to improve: [auto build test WARNING on iio/togreg] [also build test WARNING on v4.18-rc2 next-20180628] [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/Stefan-Popa/iio-dac-Add-AD5758-support/20180628-205028 base: https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git togreg reproduce: # apt-get install sparse make ARCH=x86_64 allmodconfig make C=1 CF=-D__CHECK_ENDIAN__ sparse warnings: (new ones prefixed by >>) >> drivers/iio/dac/ad5758.c:402:27: sparse: constant 65535000000 is so big it is long drivers/iio/dac/ad5758.c:413:34: sparse: constant 65535000000 is so big it is long >> drivers/iio/dac/ad5758.c:237:5: sparse: symbol 'cmpfunc' was not declared. Should it be static? Please review and possibly fold the followup patch. vim +402 drivers/iio/dac/ad5758.c 236 > 237 int cmpfunc(const void *a, const void *b) 238 { 239 return (*(int *)a - *(int *)b); 240 } 241 242 static int ad5758_find_closest_match(const int *array, 243 unsigned int size, int val) 244 { 245 int i; 246 247 for (i = 0; i < size; i++) { 248 if (val <= array[i]) 249 return i; 250 } 251 252 return size - 1; 253 } 254 255 static int ad5758_wait_for_task_complete(struct ad5758_state *st, 256 unsigned int reg, 257 unsigned int mask) 258 { 259 unsigned int timeout; 260 int ret; 261 262 timeout = 10; 263 do { 264 ret = ad5758_spi_reg_read(st, reg); 265 if (ret < 0) 266 return ret; 267 268 if (!(ret & mask)) 269 return 0; 270 271 udelay(100); 272 } while (--timeout); 273 274 dev_err(&st->spi->dev, 275 "Error reading bit 0x%x in 0x%x register\n", mask, reg); 276 277 return -EIO; 278 } 279 280 static int ad5758_calib_mem_refresh(struct ad5758_state *st) 281 { 282 int ret; 283 284 ret = ad5758_spi_reg_write(st, AD5758_KEY, 285 AD5758_KEY_CODE_CALIB_MEM_REFRESH); 286 if (ret < 0) { 287 dev_err(&st->spi->dev, 288 "Failed to initiate a calibration memory refresh\n"); 289 return ret; 290 } 291 292 /* Wait to allow time for the internal calibrations to complete */ 293 return ad5758_wait_for_task_complete(st, AD5758_DIGITAL_DIAG_RESULTS, 294 AD5758_CAL_MEM_UNREFRESHED_MSK); 295 } 296 297 static int ad5758_soft_reset(struct ad5758_state *st) 298 { 299 int ret; 300 301 ret = ad5758_spi_reg_write(st, AD5758_KEY, AD5758_KEY_CODE_RESET_1); 302 if (ret < 0) 303 return ret; 304 305 ret = ad5758_spi_reg_write(st, AD5758_KEY, AD5758_KEY_CODE_RESET_2); 306 307 /* Perform a software reset and wait 100us */ 308 udelay(100); 309 310 return ret; 311 } 312 313 static int ad5758_set_dc_dc_conv_mode(struct ad5758_state *st, 314 enum ad5758_dc_dc_mode mode) 315 { 316 int ret; 317 318 ret = ad5758_spi_write_mask(st, AD5758_DCDC_CONFIG1, 319 AD5758_DCDC_CONFIG1_DCDC_MODE_MSK, 320 AD5758_DCDC_CONFIG1_DCDC_MODE_MODE(mode)); 321 if (ret < 0) 322 return ret; 323 324 /* 325 * Poll the BUSY_3WI bit in the DCDC_CONFIG2 register until it is 0. 326 * This allows the 3-wire interface communication to complete. 327 */ 328 ret = ad5758_wait_for_task_complete(st, AD5758_DCDC_CONFIG2, 329 AD5758_DCDC_CONFIG2_BUSY_3WI_MSK); 330 if (ret < 0) 331 return ret; 332 333 st->dc_dc_mode = mode; 334 335 return ret; 336 } 337 338 static int ad5758_set_dc_dc_ilim(struct ad5758_state *st, unsigned int ilim) 339 { 340 int ret; 341 342 ret = ad5758_spi_write_mask(st, AD5758_DCDC_CONFIG2, 343 AD5758_DCDC_CONFIG2_ILIMIT_MSK, 344 AD5758_DCDC_CONFIG2_ILIMIT_MODE(ilim)); 345 if (ret < 0) 346 return ret; 347 /* 348 * Poll the BUSY_3WI bit in the DCDC_CONFIG2 register until it is 0. 349 * This allows the 3-wire interface communication to complete. 350 */ 351 return ad5758_wait_for_task_complete(st, AD5758_DCDC_CONFIG2, 352 AD5758_DCDC_CONFIG2_BUSY_3WI_MSK); 353 } 354 355 static int ad5758_slew_rate_set(struct ad5758_state *st, 356 unsigned int sr_clk_idx, 357 unsigned int sr_step_idx) 358 { 359 unsigned int mode; 360 unsigned long int mask; 361 int ret; 362 363 mask = AD5758_DAC_CONFIG_SR_EN_MSK | 364 AD5758_DAC_CONFIG_SR_CLOCK_MSK | 365 AD5758_DAC_CONFIG_SR_STEP_MSK; 366 mode = AD5758_DAC_CONFIG_SR_EN_MODE(1) | 367 AD5758_DAC_CONFIG_SR_STEP_MODE(sr_step_idx) | 368 AD5758_DAC_CONFIG_SR_CLOCK_MODE(sr_clk_idx); 369 370 ret = ad5758_spi_write_mask(st, AD5758_DAC_CONFIG, mask, mode); 371 if (ret < 0) 372 return ret; 373 374 /* Wait to allow time for the internal calibrations to complete */ 375 return ad5758_wait_for_task_complete(st, AD5758_DIGITAL_DIAG_RESULTS, 376 AD5758_CAL_MEM_UNREFRESHED_MSK); 377 } 378 379 static int ad5758_slew_rate_config(struct ad5758_state *st) 380 { 381 unsigned int sr_clk_idx, sr_step_idx; 382 int i, res; 383 s64 diff_new, diff_old; 384 u64 sr_step, calc_slew_time; 385 386 sr_clk_idx = 0; 387 sr_step_idx = 0; 388 diff_old = S64_MAX; 389 /* 390 * The slew time can be determined by using the formula: 391 * Slew Time = (Full Scale Out / (Step Size x Update Clk Freq)) 392 * where Slew time is expressed in microseconds 393 * Given the desired slew time, the following algorithm determines the 394 * best match for the step size and the update clock frequency. 395 */ 396 for (i = 0; i < ARRAY_SIZE(ad5758_sr_clk); i++) { 397 /* 398 * Go through each valid update clock freq and determine a raw 399 * value for the step size by using the formula: 400 * Step Size = Full Scale Out / (Update Clk Freq * Slew Time) 401 */ > 402 sr_step = AD5758_FULL_SCALE_MICRO; 403 do_div(sr_step, ad5758_sr_clk[i]); 404 do_div(sr_step, st->slew_time); 405 /* 406 * After a raw value for step size was determined, find the 407 * closest valid match 408 */ 409 res = ad5758_find_closest_match(ad5758_sr_step, 410 ARRAY_SIZE(ad5758_sr_step), 411 sr_step); 412 /* Calculate the slew time */ 413 calc_slew_time = AD5758_FULL_SCALE_MICRO; 414 do_div(calc_slew_time, ad5758_sr_step[res]); 415 do_div(calc_slew_time, ad5758_sr_clk[i]); 416 /* 417 * Determine with how many microseconds the calculated slew time 418 * is different from the desired slew time and store the diff 419 * for the next iteration 420 */ 421 diff_new = abs(st->slew_time - calc_slew_time); 422 if (diff_new < diff_old) { 423 diff_old = diff_new; 424 sr_clk_idx = i; 425 sr_step_idx = res; 426 } 427 } 428 429 return ad5758_slew_rate_set(st, sr_clk_idx, sr_step_idx); 430 } 431 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
