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How to carry out RK3399 Linux4.4 Audio development, in view of this problem, this article introduces the corresponding analysis and answers in detail, hoping to help more partners who want to solve this problem to find a more simple and feasible method.

RK3399's CPU adopts big.LITTLE large and small core architecture, double Cortex-A72 large core + four Cortex-A53 small core structure, greatly optimizes integer, floating point, memory, etc., and revolutionizes the overall performance, power consumption and core area. RK3399's GPU uses a new generation of quad-core ARM high-end image processor Mali-T860, integrates more bandwidth compression technologies such as intelligent superposition, ASTC, local pixel storage, etc., and supports more graphics and computing interfaces, with an overall performance improvement of 45% over the previous generation.

RK3399 Android motherboard is designed for the application development of consumer electronics, intelligent terminals, MID, wireless communications, medical equipment, industrial control and other industries, with strong video processing capabilities, ultra-high definition video output advantages, rich interfaces and stable performance. Support Android\ Linux\ Ubuntu system, perfect software support, open source code suitable for the secondary development of commercial display advertising machines with high-definition display, self-service vending machines, educational terminals, etc., can reduce the threshold of research and development, shorten the product development cycle.

Audio Development Guide

A sound card consists of cpu_dai, codec_dai, and dai_link, corresponding to the dirver of cpu dai, such as I ²S driver, spdif driver; codec driver, such as rt5640 codec driver; dai_link driver, that is, machine driver, such as sound/soc/rockchip/rockchip_rt5640.c. The kernel of 4. 4. 4 supports two ways to create sound cards, one is general-purpose simple-card framework, and the other is traditional writing custom machine driver to create sound cards. Rt5640 is used as an example in this document.

Simple-card

Simple card is a simple and general-purpose machine driver. If the simple-card framework is sufficient to meet the needs, it is recommended to give priority to using the simple card framework, which is simple, convenient and easy to use.

1. Add codec driver, such as: sound/soc/codec/rt5640.c

two。 Modify sound/soc/codec/Kconfig and Makefile to add driver compilation

Enable simple card and codec in 3.menuconfig

4. Add Simple Card Node to the DTS of the product

It should be noted that if the clocks of rt5640 is mclk, the upstream code follows the original rule of who uses clk and who applies, so if you add codec driver later, if you use external clk as mclk, you need to make the same adaptation.

Custom Machine Driver

When simple card is not enough to meet the requirements, you need to write a corresponding machine driver, such as sound/soc/rockchip/rockchip_rt5640.c, and then add special controls, routing, and so on to the machine driver. No examples are given here, the original format is continued, and there are reference codes under the directory as a reference.

This is the answer to the question about how to develop RK3399 Linux4.4 Audio. I hope the above content can be of some help to you. If you still have a lot of doubts to solve, you can follow the industry information channel to learn more about it.

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