PLANE_CTL_ALPHA_MASK
alpha = REG_FIELD_GET(PLANE_CTL_ALPHA_MASK, val);
#define PLANE_CTL_ALPHA_DISABLE REG_FIELD_PREP(PLANE_CTL_ALPHA_MASK, 0)
#define PLANE_CTL_ALPHA_SW_PREMULTIPLY REG_FIELD_PREP(PLANE_CTL_ALPHA_MASK, 2)
#define PLANE_CTL_ALPHA_HW_PREMULTIPLY REG_FIELD_PREP(PLANE_CTL_ALPHA_MASK, 3)
val & PLANE_CTL_ALPHA_MASK,