Currently in its second version, the following
patchseries has been developed and submitted to relevant mailing lists. It adds ASoC (ALSA SoC) drivers for the Sound Interface Unit (SIU), found on several sh CPUs. The series also adds a driver for the WM8978 stereo audio codec from
Wolfson Microelectronics, as well as board support for the sh7722-based Migo-R board. Drivers have been tested with stereo playback and capture with various sampling rates. They are based on earlier work from another author, as can be seen from driver headers, but drivers have been practically completely rewritten. The original driver contained built-in firmware, was a pure ALSA driver, used direct register accesses to configure DMA, pin functions, used physical addresses to access the hardware, used hard-coded register addresses. The new version is an ASoC driver, it uses the dmaengine interface for DMA functionality (see a previous
post for slave DMA support for sh), firmware is loaded from the user-space using the standard hotplug functionality, it uses runtime pm and generic clock APIs to manage CPU clocks. Although currently only tested on sh7722, the same SIU hardware is also present on other chips, e.g., sh7343, sh7354, sh7367.
