SPISG_CLK_DIV_MIN
#define DIV_NUM (SPISG_CLK_DIV_MAX - SPISG_CLK_DIV_MIN + 1)
tbl[i].val = i + SPISG_CLK_DIV_MIN - 1;
tbl[i].div = i + SPISG_CLK_DIV_MIN;
FIELD_PREP(CFG_CLK_DIV, SPISG_CLK_DIV_MIN - 1));