SDHCI_CLOCK_MUL_MASK
caps1 &= ~SDHCI_CLOCK_MUL_MASK;
caps1 |= FIELD_PREP(SDHCI_CLOCK_MUL_MASK, clk_mul);
host->clk_mul = FIELD_GET(SDHCI_CLOCK_MUL_MASK, host->caps1);