scope.clock.clkgen_freq = 32e6 causes CW to generate an internal 32 MHz clock. This clock can be provided to the target if you set e.g. scope.io.hs2 = 'clkgen'.
scope.clock.adc_src = “clkgen_x1” means take that internal clock, multiply it by 1 (the other option being to multiply it by 4, by setting it to clkgen_x4), and use that as the ADC sampling clock. So, scope.clock.adc_freq would be 32e6.