REG_TWSIC1
c1 = mcam_reg_read(mcam, REG_TWSIC1);
(void) mcam_reg_read(mcam, REG_TWSIC1); /* force write */
mcam_reg_write(mcam, REG_TWSIC1, rval);
rval = mcam_reg_read(mcam, REG_TWSIC1);
c1 = mcam_reg_read(mcam, REG_TWSIC1);
(void) mcam_reg_read(mcam, REG_TWSIC1); /* force write */
mcam_reg_write(mcam, REG_TWSIC1, rval);
rval = mcam_reg_read(mcam, REG_TWSIC1);