On 21-07-18, 13:06, Paul Cercueil wrote: > +static const struct jz4780_dma_soc_data jz4780_dma_soc_data[] = { > + [ID_JZ4780] = { .nb_channels = 32, }, why the array of structs? > +}; > + > +static const struct of_device_id jz4780_dma_dt_match[] = { > + { .compatible = "ingenic,jz4780-dma", .data = (void *)ID_JZ4780 }, the data should be jz4780_dma_soc_data? as you would add more data later.. and not the enum.. > - jzdma = devm_kzalloc(dev, sizeof(*jzdma), GFP_KERNEL); > + version = (enum jz_version)of_id->data; > + soc_data = &jz4780_dma_soc_data[version]; this can be simplified if we do: soc_data = device_get_match_data(pdev); with: static const struct jz4780_dma_soc_data jz4780_dma_soc_data = { .nb_channels = 32, }; and { .compatible = "ingenic,jz4780-dma", .data = (void *)jz4780_dma_soc_data }, You add more parameters in future patches and store soc_data in driver object and use as is.. > + jzdma = devm_kzalloc(dev, sizeof(*jzdma) > + + sizeof(*jzdma->chan) * soc_data->nb_channels, > + GFP_KERNEL); > if (!jzdma) > return -ENOMEM; > > + jzdma->soc_data = soc_data; > + jzdma->version = version; why do you need to store version, driver should handle values and not versions.. -- ~Vinod