On Mar 5, 2015, at 7:51 PM, Kenneth Westfield <kwestfie@xxxxxxxxxxxxxx> wrote: > On Thu, Mar 05, 2015 at 12:52:30PM -0600, Kumar Gala wrote: >> >> On Mar 3, 2015, at 6:21 PM, Kenneth Westfield <kwestfie@xxxxxxxxxxxxxx> wrote: >> >>> +++ b/Documentation/devicetree/bindings/sound/qcom,lpass-cpu.txt >>> @@ -0,0 +1,49 @@ >>> +* Qualcomm Technologies LPASS CPU DAI >>> + >>> +Required subnodes: >>> + >>> +- qcom,adsp : Audio DSP sub-node >>> + >>> +Optional Audio DSP subnode properties: >>> + >>> +- status : "disabled" indicates the adsp is not available. >>> + >> >> What is the intent of this subnode? >> > > From the cover letter: > Even though the ipq806x LPASS does not contain an audio DSP, other SOCs > do have one. For those SOCs, the audio DSP typically controls the > hardware blocks in the LPASS. Hence, different CPU DAI driver(s) would > need to be used in order to facilitate audio with the DSP. As such, the > LPASS DT contains an adsp subnode, which is disabled for this SOC. The > same subnode should be enabled and populated for other SOCs that do > contain an audio DSP. Not using the audio DSP would require different > CPU DAI driver(s), in addition to possible bootloader and/or firmware > changes. > > This was the result of a request from Mark. See here: > http://thread.gmane.org/gmane.linux.drivers.devicetree/109331/focus=11633 Two quick comments before I read Mark’s comments. 1. Its not normal practice to put something into a DT that does not exist. Having a node, but marking it disabled implies existence. 2. How would one normally address the audio DSP if it did exist. I’m just wondering if having a subnode is the proper solution vs maybe a phandle - k -- Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
