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| author | Haavard Skinnemoen <haavard.skinnemoen@atmel.com> | 2008-10-23 15:24:10 +0200 |
|---|---|---|
| committer | Haavard Skinnemoen <haavard.skinnemoen@atmel.com> | 2008-10-23 15:24:10 +0200 |
| commit | d9214556b11a8d18ff588e60824c12041d30f791 (patch) | |
| tree | 04ab59d13961675811a55c96fb12b2b167b72318 /Documentation/powerpc/dts-bindings/fsl/ssi.txt | |
| parent | 72a1419a9d4c859a3345e4b83f8ef7d599d3818c (diff) | |
| parent | e82c6106b04b85879d802bbbeaed30d9b10a92e2 (diff) | |
Merge branches 'boards' and 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/hskinnemoen/avr32-2.6
Diffstat (limited to 'Documentation/powerpc/dts-bindings/fsl/ssi.txt')
| -rw-r--r-- | Documentation/powerpc/dts-bindings/fsl/ssi.txt | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/Documentation/powerpc/dts-bindings/fsl/ssi.txt b/Documentation/powerpc/dts-bindings/fsl/ssi.txt index d100555d488a..a2d963998a65 100644 --- a/Documentation/powerpc/dts-bindings/fsl/ssi.txt +++ b/Documentation/powerpc/dts-bindings/fsl/ssi.txt @@ -24,6 +24,12 @@ Required properties: "rj-master" - r.j., SSI is clock master "ac97-slave" - AC97 mode, SSI is clock slave "ac97-master" - AC97 mode, SSI is clock master +- fsl,playback-dma: phandle to a node for the DMA channel to use for + playback of audio. This is typically dictated by SOC + design. See the notes below. +- fsl,capture-dma: phandle to a node for the DMA channel to use for + capture (recording) of audio. This is typically dictated + by SOC design. See the notes below. Optional properties: - codec-handle : phandle to a 'codec' node that defines an audio @@ -36,3 +42,20 @@ Child 'codec' node required properties: Child 'codec' node optional properties: - clock-frequency : The frequency of the input clock, which typically comes from an on-board dedicated oscillator. + +Notes on fsl,playback-dma and fsl,capture-dma: + +On SOCs that have an SSI, specific DMA channels are hard-wired for playback +and capture. On the MPC8610, for example, SSI1 must use DMA channel 0 for +playback and DMA channel 1 for capture. SSI2 must use DMA channel 2 for +playback and DMA channel 3 for capture. The developer can choose which +DMA controller to use, but the channels themselves are hard-wired. The +purpose of these two properties is to represent this hardware design. + +The device tree nodes for the DMA channels that are referenced by +"fsl,playback-dma" and "fsl,capture-dma" must be marked as compatible with +"fsl,ssi-dma-channel". The SOC-specific compatible string (e.g. +"fsl,mpc8610-dma-channel") can remain. If these nodes are left as +"fsl,elo-dma-channel" or "fsl,eloplus-dma-channel", then the generic Elo DMA +drivers (fsldma) will attempt to use them, and it will conflict with the +sound drivers. |