RASPBERRYPI_FREQ_INTERVAL
min = roundup(clk_round_rate(clk, 0), RASPBERRYPI_FREQ_INTERVAL);
max = roundup(clk_round_rate(clk, ULONG_MAX), RASPBERRYPI_FREQ_INTERVAL);
for (rate = min; rate <= max; rate += RASPBERRYPI_FREQ_INTERVAL) {