  LHCb has collected the world's largest sample of charmed hadrons. This sample
is used to measure the mixing parameters in the $D^0$-$\bar{D}^0$ system and to
search for indirect $CP$ violation. This contribution focuses on measurements
of $A_{\Gamma}$ with $D^*$ and semileptonic $B$ decays and on mixing
measurements and a search for $CP$ violation in $D\to K\pi$ decays.
