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>>>>> >>>>> + if (!of_property_present(i2c_dev->dev->of_node, "dmas")) { >>>>> + dev_dbg(i2c_dev->dev, "DMA not available, falling back to PIO\n"); >>>>> + return 0; >>>>> + } >>>>> + >>>>> if (i2c_dev->hw->has_apb_dma) { >>>>> if (!IS_ENABLED(CONFIG_TEGRA20_APB_DMA)) { >>>>> dev_dbg(i2c_dev->dev, "APB DMA support not enabled\n"); >>>> >>>> What about ACPI based devices? >>> >>> The of_ function returns false if using ACPI. Since these DMA drivers does >>> not support ACPI enumeration currently, we would not require to proceed >>> further anyway. But if required we can add an additional check with >>> acpi_dma_supported() or similar. Do you suggest adding a check for ACPI? >> >> I was just wondering if it is better to use fwnode_property_present() >> instead. > > I think ACPI does not use 'dmas' property to connect a DMA resource. > It uses FixedDMA or something similar. It may not be helpful to use > fwnode_*() or device_*() check here in that case. OK. Then fine to leave this as-is. Jon -- nvpublic