* Nishanth Menon <nm@xxxxxx> [201026 14:58]: > On 13:38-20201007, Peter Ujfalusi wrote: > [...] > > >>>> + status = "disabled"; > > >>> > > >>> I see that there is inconsistent usage of "disabled" in our SoC.dts > > >>> > > >>> Our generic rule has been set them to disabled in board.dtsi > > >>> McASP and DSS for existing SoC dts do not follow this.. which is a tad > > >>> confusing.. (considering that not even all uarts come out on every board > > >>> and every uart needs pinmux to function..) > > >> > > >> "keep them disabled because several required properties are not present > > >> as they are board specific." > > >> > > >> In board file the enabled mcasp must be updated with options that is > > >> required for operation. Without those option the McASP can not be > > >> initialized. > > >> > > >> I think we have been revisiting the very same discussion every time we > > >> have a new SoC with McASP... > > >> > > > > > > Yep.. This doe'snt really follow the rest of the SoC definition. [1] > > > came to mind. The McASP discussion is a variation in the debate of the > > > same. > > > > Right, saying status = "okay" to a node which is missing required > > properties (which can only be added by boards when the McASP is > > connected up) does not sound a good solution. > > How should the SW handle that? Fail the device probe and return with > > -EINVAL or eat up the error and just probe with broken configuration. > > Since the peripheral is not used, the broken configuration will not > > cause much runtime errors as there will be no runtime use of the peripheral. > > > > status of fail or fail-sss is not a good one either, their definition is: > > "Indicates that the device is not operational. A serious error was > > detected in the device, and it is unlikely to become operational without > > repair." > > > > The peripheral is fine, we are just trying to enable it without > > providing the needed properties. > > > > > I'd argue Serdes, or for that matter any IP that has a link to > > > outside-the-SoC world has the same discussion point. > > > > status = "disabled" is still the closest thing for everything which have > > external dependencies. There is not much point to enable an i2c bus > > without making sure that the signals are actually routed to the pins > > where they supposed to go. There is one reason to keep using the default status = "okay", for i2c Linux can properly idle the device on boot without dependencies to a certain boot loader version. > > Or from other pow: a board design is not based on what is _not_ > > connected to outside world, but you actually _connect_ or _enable_ > > certain peripherals to external components, connectors. > > OK, I will buy the argument that the current status thingy is a bit > overloaded and does'nt imply the correct state we need it to imply with > "fail-sss" either - I remember an argument for "fail-incomplete", but > that never happened anyways. > > Lets add this argument to the commit message and repost after testing > on 5.10-rc1 please? We should use status = "disabled" when the hardware is not accessible to the SoC. That goes for things like secure world devices, and hardware that relies on a missing external clock for example. For other things we should just stick to the default which "okay" :) Regards, Tony
