TIM2_CH1_ETR is really bundling 2 functions to the same pin: TIM2_CH1 (where its used as a channel) TIM2_ETR (where iss used as an external trigger). I fixed most of these a while back, but it looks like I missed this one.
Trying to move towards consistency, let's use _ exclusively in names of source files (eg .c, .h, .csv).