On Thu, 20 Feb 2025 19:03:30 +0100 Angelo Dureghello <adureghello@xxxxxxxxxxxx> wrote: > From: Angelo Dureghello <adureghello@xxxxxxxxxxxx> > > Add support for SPI offload to the ad7380 driver. SPI offload allows > sampling data at the max sample rate (2MSPS with one SDO line). > > This is developed and tested against the ADI example FPGA design for > this family of ADCs [1]. > > [1]: http://analogdevicesinc.github.io/hdl/projects/ad738x_fmc/index.html > > Signed-off-by: Angelo Dureghello <adureghello@xxxxxxxxxxxx> Just one trivial comment from me that I can tidy up when applying if nothing else comes up. However, I'd like David to take a look at this before I apply (+ anyone else who has time!) Jonathan > diff --git a/drivers/iio/adc/ad7380.c b/drivers/iio/adc/ad7380.c > index a18dcd664c1b5e5032cc55c063e5681d11c23352..492356eed9a9f86c27a00cf1e280bd6432ed30b2 100644 > --- a/drivers/iio/adc/ad7380.c > +++ b/drivers/iio/adc/ad7380.c > @@ -15,6 +15,9 @@ > +static int ad7380_probe_spi_offload(struct iio_dev *indio_dev, > + struct ad7380_state *st) > +{ > + struct spi_device *spi = st->spi; > + struct device *dev = &spi->dev; > + struct dma_chan *rx_dma; > + int sample_rate, ret; > + > + indio_dev->setup_ops = &ad7380_offload_buffer_setup_ops; > + indio_dev->channels = st->chip_info->offload_channels; > + /* Just removing the timestamp channel. */ > + indio_dev->num_channels--; > + > + st->offload_trigger = devm_spi_offload_trigger_get(dev, st->offload, > + SPI_OFFLOAD_TRIGGER_PERIODIC); > + if (IS_ERR(st->offload_trigger)) > + return dev_err_probe(dev, PTR_ERR(st->offload_trigger), > + "failed to get offload trigger\n"); > + > + sample_rate = st->chip_info->max_conversion_rate_hz * > + AD7380_NUM_SDO_LINES / st->chip_info->num_simult_channels; > + > + st->sample_freq_range[0] = 1; /* min */ > + st->sample_freq_range[1] = 1; /* step */ > + st->sample_freq_range[2] = sample_rate; /* max */ > + > + /* > + * Starting with a quite low frequency, to allow oversampling x32, > + * user is then reponsible to adjust the frequency for the specific case. > + */ > + ret = ad7380_set_sample_freq(st, sample_rate / 32); > + if (ret) > + return ret; > + > + rx_dma = devm_spi_offload_rx_stream_request_dma_chan(dev, st->offload); > + if (IS_ERR(rx_dma)) > + return dev_err_probe(dev, PTR_ERR(rx_dma), > + "failed to get offload RX DMA\n"); > + > + ret = devm_iio_dmaengine_buffer_setup_with_handle(dev, indio_dev, > + rx_dma, IIO_BUFFER_DIRECTION_IN); > + if (ret) > + return dev_err_probe(dev, ret, "cannot setup dma buffer\n"); > + > + return ret; return 0; as it can't be anything else. > +}
