October 2017
Intermediate to advanced
586 pages
14h 8m
English
Content preview from Linux Device Drivers Development
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Platform resources and DTs
Platform devices can work with a DT-enabled system without any extra modification. This is what we demonstrated in the Handling resources section. By using the platform_xxx family function, the core also walks-through a DT (with the of_xxx family function) to find the requested resource. The reverse is not true, since the of_xxx family function is only reserved for the DT. All resource data will be available to the driver in the usual way. The driver now knows whether this device is initialized with hardcoded parameters in the board file or not. Let's take an example with a uart device node:
uart1: serial@02020000 { compatible = "fsl,imx6q-uart", "fsl,imx21-uart"; reg = <0x02020000 0x4000>; interrupts = <0 26 IRQ_TYPE_LEVEL_HIGH>; ...