CLKSEL_MASK
cg_out(hwc->cg, (clksel << CLKSEL_SHIFT) & CLKSEL_MASK, hwc->reg);
clksel = (cg_in(hwc->cg, hwc->reg) & CLKSEL_MASK) >> CLKSEL_SHIFT;
clksel = (cg_in(cg, hwc->reg) & CLKSEL_MASK) >> CLKSEL_SHIFT;
#define CLKSEL_STOP FIELD_PREP(CLKSEL_MASK, 0)
#define CLKSEL_GEN FIELD_PREP(CLKSEL_MASK, 1)
#define CLKSEL_EXT FIELD_PREP(CLKSEL_MASK, 2)