[PATCH 5/9] clk: qcom: gcc-msm8960: add child devices support.
From: Rajendra Nayak <hidden>
Date: 2015-09-07 06:39:34
Also in:
linux-arm-msm, linux-pm
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No. The driver should work just fine without having to interrogate the device's compatible string. If we still need the compatible check for some reason, then we can always match based on qcom,gcc-msm8960, qcom,gcc-apq8064, etc. But I don't see whyThats not quite possible I guess. 2 drivers (gcc and tsens) matching the same compatibles? Will it not just depend on which ends up being the first match?Any thoughts on how to move forward with this? I tried what you were suggesting, and here's what I had to do to get things working * Created a gcc node in DT with gcc and tsens compatibles, with gcc and tsens propertiesThis is not what I had in mind. This is what's should be in DT clock-controller at f000 { compatible = "qcom,gcc-msm8916"; reg = <0xf000 ...>; .... };quoted
* gcc driver probes the device/node first given gcc is registered with a core_initcall() * creates a virtual child device attaching the same of_node (having both gcc and tsens compatibles) * gcc ends up probing the virtual device/node _again_ (due to the gcc compatible match), fails * At a later point, tsens driver gets registered (using module_initcall) ends up probing the virtual child node and succeedsYeah this might happen though because we've assigned the of_node pointer to the tsens device before we register it on the platform bus. The other way to pass that data down from gcc to tsens would be to not have an of_node assigned to the tsens device, and check for that case in the tsens driver. If there isn't an of_node, then we look at the parent device's of_node to figure out which gcc it is (if this even matters) and parse DT properties.
Parsing DT properties from parent (in the tsens driver) is fine, but the nvmem apis still expect an of_node for the tsens device and hence fail. Associating the of_node of the parent to the tsens device while being probed ends up with the same issues of gcc ending up probing the device and failing because tsens defers probe a couple times before a successful probe.