tjh.dev / kernel
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i2c: designware: Do not calculate SCL timing parameters needlessly

Do SCL timing parameter calculation conditionally depending are custom
parameters provided since calculated values will get instantly overwritten
by provided parameters.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

authored by

Jarkko Nikula and committed by
Wolfram Sang 42ffd390 c680eed5

+22 -23
+22 -23
drivers/i2c/busses/i2c-designware-core.c
··· 320 320 sda_falling_time = dev->sda_falling_time ?: 300; /* ns */ 321 321 scl_falling_time = dev->scl_falling_time ?: 300; /* ns */ 322 322 323 - /* Standard-mode */ 324 - hcnt = i2c_dw_scl_hcnt(input_clock_khz, 325 - 4000, /* tHD;STA = tHIGH = 4.0 us */ 326 - sda_falling_time, 327 - 0, /* 0: DW default, 1: Ideal */ 328 - 0); /* No offset */ 329 - lcnt = i2c_dw_scl_lcnt(input_clock_khz, 330 - 4700, /* tLOW = 4.7 us */ 331 - scl_falling_time, 332 - 0); /* No offset */ 333 - 334 - /* Allow platforms to specify the ideal HCNT and LCNT values */ 323 + /* Set SCL timing parameters for standard-mode */ 335 324 if (dev->ss_hcnt && dev->ss_lcnt) { 336 325 hcnt = dev->ss_hcnt; 337 326 lcnt = dev->ss_lcnt; 327 + } else { 328 + hcnt = i2c_dw_scl_hcnt(input_clock_khz, 329 + 4000, /* tHD;STA = tHIGH = 4.0 us */ 330 + sda_falling_time, 331 + 0, /* 0: DW default, 1: Ideal */ 332 + 0); /* No offset */ 333 + lcnt = i2c_dw_scl_lcnt(input_clock_khz, 334 + 4700, /* tLOW = 4.7 us */ 335 + scl_falling_time, 336 + 0); /* No offset */ 338 337 } 339 338 dw_writel(dev, hcnt, DW_IC_SS_SCL_HCNT); 340 339 dw_writel(dev, lcnt, DW_IC_SS_SCL_LCNT); 341 340 dev_dbg(dev->dev, "Standard-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt); 342 341 343 - /* Fast-mode */ 344 - hcnt = i2c_dw_scl_hcnt(input_clock_khz, 345 - 600, /* tHD;STA = tHIGH = 0.6 us */ 346 - sda_falling_time, 347 - 0, /* 0: DW default, 1: Ideal */ 348 - 0); /* No offset */ 349 - lcnt = i2c_dw_scl_lcnt(input_clock_khz, 350 - 1300, /* tLOW = 1.3 us */ 351 - scl_falling_time, 352 - 0); /* No offset */ 353 - 342 + /* Set SCL timing parameters for fast-mode */ 354 343 if (dev->fs_hcnt && dev->fs_lcnt) { 355 344 hcnt = dev->fs_hcnt; 356 345 lcnt = dev->fs_lcnt; 346 + } else { 347 + hcnt = i2c_dw_scl_hcnt(input_clock_khz, 348 + 600, /* tHD;STA = tHIGH = 0.6 us */ 349 + sda_falling_time, 350 + 0, /* 0: DW default, 1: Ideal */ 351 + 0); /* No offset */ 352 + lcnt = i2c_dw_scl_lcnt(input_clock_khz, 353 + 1300, /* tLOW = 1.3 us */ 354 + scl_falling_time, 355 + 0); /* No offset */ 357 356 } 358 357 dw_writel(dev, hcnt, DW_IC_FS_SCL_HCNT); 359 358 dw_writel(dev, lcnt, DW_IC_FS_SCL_LCNT);