When reading pages 13-14 of the IMX6Q hardware development guide it seems to suggest that you can use an external clock source instead of a crystal for the 24MHz input clock. However it is unclear whether this clock source must be hooked to the XTALI pin or whether you can leave the XTALI unconnected and use the CLK1_N, CLK1_P or CLK2_N, CLK2_P pins instead. The XTAL pins use the NVCC_PLL_OUT power group (1.1V) so it seems to me as though you would have to get an external clock that does not switch at a voltage level above 1.1V. I have had much difficulty finding an external clock source like this and i don't know if one exists.
1. Can the the XTAL pins be driven by a 1.8V clock source?
2. Can the CLK pins be used instead of the XTAL pins? (XTAL pins grounded)