08-27-2021, 12:21 PM
It provides a way to support I2S audio devices that are not listed in the Named device list. Below is the help text.
For example if you have the Cirrus Logic Audio Card its not listed in the Named device list but it's overlay (driver) "rpi-cirrus-wm5102" can be selected from the DT overlay list. This allows you to play audio via the card.
If it made sense to expend the effort to integrate this device into the Named list then you would select it from there and its overlay would automatically be loaded. If the card had special chip options, input switching etc we would be able to create UI and configurations to handle those as part of the effort to integrate the device.
Code:
Named devices provide descriptive information and may also provide configurable driver and/or chip options accessible from the UI. Device Tree (DT) overlays provide an I2S interface for a device but without integrated UI access to any driver or chip options. Contact the device manufacturer for information on which overlay to use.For example if you have the Cirrus Logic Audio Card its not listed in the Named device list but it's overlay (driver) "rpi-cirrus-wm5102" can be selected from the DT overlay list. This allows you to play audio via the card.
If it made sense to expend the effort to integrate this device into the Named list then you would select it from there and its overlay would automatically be loaded. If the card had special chip options, input switching etc we would be able to create UI and configurations to handle those as part of the effort to integrate the device.
