REG_RBCPR_CTL
ctl = cpr_read(drv, REG_RBCPR_CTL);
cpr_masked_write(drv, REG_RBCPR_CTL, mask, value);
cpr_masked_write(drv, REG_RBCPR_CTL,
reg_val = cpr_read(drv, REG_RBCPR_CTL);
corner->save_ctl = cpr_read(drv, REG_RBCPR_CTL);
cpr_write(drv, REG_RBCPR_CTL, ctl);
val = cpr_read(drv, REG_RBCPR_CTL);
cpr_write(drv, REG_RBCPR_CTL, 0);
cpr_write(drv, REG_RBCPR_CTL, val);