Does anyone know how to make DMA work on STM32 ADC? Having a struggle there too. So far, unable to get DMA working on any peripheral. Code highlights. Works fine with non-DMA:

```rust
    let mut dma = Dma::new(dp.DMA1, &mut dp.RCC);
    let mut buf = DmaReadBuf { buf: &[0_u8; 1]};

    loop {
        adc.read_dma(&buf, 15, DmaChannel::C1, &mut dma);
        defmt::info!("Reading: {:?}", &buf.buf);
        delay.delay_ms(1_000);
    }
```