Messages in this thread |  | | Date | Wed, 30 Jun 2021 13:33:58 +0100 | From | Lee Jones <> | Subject | Re: [PATCH] mfd: mfd-core: Change "Failed to locate of_node" warning to debug |
| |
On Wed, 30 Jun 2021, Daniel Thompson wrote:
> On Wed, Jun 30, 2021 at 07:27:32AM +0000, Yunus Bas wrote: > > Am Dienstag, dem 29.06.2021 um 14:39 +0100 schrieb Lee Jones: > > > On Tue, 29 Jun 2021, Yunus Bas wrote: > > > > Interestingly, all subdevices defined in the driver are registered > > > > as platform devices from the MFD framework, regardless of a > > > > devicetree entry or not. The preceding code checks the subdevice > > > > cells with an additional compatible. In case a device has no > > > > devicetree entry, an irritating failed-message is printed on the > > > > display. I'm not sure if this was the intention but the framework > > > > somehow forces the users to describe all subdevices of an MFD. I > > > > think the info print is not needed. It makes more sense to set it > > > > as a debug print. > > > > > > Actually, this has served to highlight that your DTS is not correct. > > > > > > Why are some devices represented in DT and some aren't? > > > > > > If anything, I'm tempted to upgrade the info() print to warn(). > > > > Imagine only required parts of the MFD is connected to the designed > > system and unrequired parts are not. In that case, fully describing the > > MFD in the devicetree wouldn't represent the system at all. > > To describe hardware that is present but unused we would normally use > status = "disabled". > > So if, for example, your board cannot use the RTC for some reason > (perhaps the board has no 32KHz oscillator?) then the DA9062 still > contains the hardware but it is useless. Such hardware could be > described as: > > da9062_rtc: rtc { > compatible = "dlg,da9062-rtc"; > status = "disabled"; > } > > Is this sufficient to suppress the warnings when the hardware is not > fully described? > > There is almost certainly a problem here since there is a mismatch > between mfd-core and the DA9062 DT bindings. mfd-core warns when the > hardware description is incomplete and the DA9062 (and generic mfd) DT > bindings are ambiguous about whether sub-nodes are mandatory and include > an example that contains missing compatibles rather than disabled nodes > like the above. > > However it is not entirely clear to me at this point whether this should > be fixed in mfd-core or by improving the bindings documentation.
Right. This is a potential solution.
NB: The suggestion above is usually the default for devices (at least this was the case back when I was neck deep in DT). You usually have the a device specified in a DTSI file with the generic properties defined from within a top-level node which is usually disabled. Then you link back to that node (usually with a &) from within your DTS file where you provide platform specific properties and override the status to 'okay' or what have you.
However before I provide any further assistance, I really want to get an idea of the H/W you're working with. Is this a reduced function DA9062? Or is the functionality actually present, you just don't want to make use of it?
-- Lee Jones [李琼斯] Senior Technical Lead - Developer Services Linaro.org │ Open source software for Arm SoCs Follow Linaro: Facebook | Twitter | Blog
|  |