On Tue, Mar 7, 2023 at 7:17 AM Benjamin Tissoires
<benjamin.tissoires@xxxxxxxxxx> wrote:
>
> On Mar 06 2023, Andy Shevchenko wrote:
> > On Mon, Mar 06, 2023 at 01:40:16PM -0600, Daniel Kaehn wrote:
> >
> > ...
> >
> > > Device (SE9)
> > > {
> > > Name (_ADR, 0x001D0001) // _ADR: Address
> > > Device (RHUB)
> > > {
> > > Name (_ADR, Zero)
> > > Device (CP2) // the USB-hid & CP2112 shared node
> > > {
> > > Name (_ADR, One)
> > > }
> > > }
> > > }
> > >
> > > If I'm understanding correctly, this adds the SE9 device as function 1
> > > of PCI device 0x1d,
> >
> > To be precise this does not add the device. It adds a description of
> > the companion device in case the real one will appear on the PCI bus
> > with BDF 00:1d.1.
> >
> > > then RHUB as the USB controller it provides, and finally, CP2 as the
> > > USB device attached to port 1 of the controller.
> > >
> > > With this as the loaded dsdt table, the USB device now has a firmware_node :)
> > > #> cat /sys/bus/usb/devices/3-1:1.0/firmware_node/path
> > > \_SB_.PCI0.SE9_.RHUB.CP2_
> > >
> > > After applying my patches, the HID device also references this node:
> > > #> cat /sys/bus/hid/devices/0003:10C4:EA90.0003/firmware_node/path
> > > \_SB_.PCI0.SE9_.RHUB.CP2_
> > >
>
> Great! Thanks a lot for that. Turns out that with both of your inputs I
> can also do the same, but without the need for OVMF and DSDT patching,
> with just an SSDT override.
>
Ah, interesting.. I tried the SSDT override route initially, but tried
applying it
through EFI variables and through configfs, neither of which worked since
they appeared to be applied after the relevant drivers were already loaded
(at least that was my suspicion). I wonder if loading the overlay through the
initramfs was the key.
> Turns out that the override documentation [1] mentions "This option
> allows loading of user defined SSDTs from initrd and it is useful when
> the system does not support EFI or ..."
>
> FWIW, I am attaching my full DSDT override in case it is valuable:
> (on my system, the default USB controller (non-xhc) is at PCI address
> 1.2, which explains the slight difference). It can be loaded in the same
> way you are overriding the full DSDT, but with just that compilation
> output:
>
> ---
> DefinitionBlock ("cp2112.aml", "SSDT", 5, "", "CP2112", 1)
> {
> External (_SB_.PCI0, DeviceObj)
>
> Scope (\_SB_.PCI0)
> {
> Device (USB0)
> {
> Name (_ADR, 0x00010002) // _ADR: Address
> Device (RHUB)
> {
> Name (_ADR, Zero)
> Device (CP21) // the USB-hid & CP2112 shared node
> {
> Name (_ADR, One)
> Device (I2C)
> {
> Name (_ADR, Zero)
> Name (_STA, 0x0F)
> }
>
> Device (GPIO)
> {
> Name (_ADR, One)
> Name (_STA, 0x0F)
> }
> }
> }
> }
> }
To get this to work -- I assume you had to change the driver to look
for uppercase
"GPIO" and "I2C", or some similar change?
>
> Scope (\_SB_.PCI0.USB0.RHUB.CP21.I2C)
> {
> Device (TPD0)
> {
> Name (_HID, "RMI40001")
> Name (_CID, "PNP0C50")
> Name (_STA, 0x0F)
>
> Name (SBFB, ResourceTemplate ()
> {
> I2cSerialBusV2 (0x00c, ControllerInitiated, 100000,
> AddressingMode7Bit, "\\_SB_.PCI0.USB0.RHUB.CP21.I2C",
> 0x00, ResourceConsumer,, Exclusive,
> )
> })
> Name (SBFG, ResourceTemplate ()
> {
> GpioInt (Level, ActiveLow, Exclusive, PullDefault, 0x0000,
> "\\_SB_.PCI0.USB0.RHUB.CP21.GPIO", 0x00, ResourceConsumer, ,
> )
> { // Pin list
> 0x0002
> }
> })
> Method(_CRS, 0x0, NotSerialized)
> {
> Return (ConcatenateResTemplate (SBFB, SBFG))
> }
>
> Method(_DSM, 0x4, Serialized)
> {
> // DSM UUID
> switch (ToBuffer (Arg0))
> {
> // ACPI DSM UUID for HIDI2C
> case (ToUUID ("3CDFF6F7-4267-4555-AD05-B30A3D8938DE"))
> {
> // DSM Function
> switch (ToInteger (Arg2))
> {
> // Function 0: Query function, return based on revision
> case(0)
> {
> // DSM Revision
> switch (ToInteger (Arg1))
> {
> // Revision 1: Function 1 supported
> case (1)
> {
> Return (Buffer (One) { 0x03 })
> }
>
> default
> {
> // Revision 2+: no functions supported
> Return (Buffer (One) { 0x00 })
> }
> }
> }
>
> // Function 1 : HID Function
> case(1)
> {
> // HID Descriptor Address
> Return (0x0020)
> }
>
> default
> {
> // Functions 2+: not supported
> Return (Buffer (One) { 0x00 })
> }
> }
> }
>
> default
> {
> // No other GUIDs supported
> Return (Buffer (One) { 0x00 })
> }
> }
> }
> }
> }
> }
> ---
>
> This almost works. Almost because the I2C device is correctly created,
> but I have an issue with the GpioInt call which is not properly set by
> the kernel and which returns -EDEFER. /o\
>
Ahh, yep, I've had this issue as well -- I suspect the issue you're
having is that the
CP2112 driver initializes the i2c controller before the gpiochip, and
if any i2c devices
on the bus depend on the CP2112's gpio, the probe will never succeed!
I have made
and been testing with a patch to fix this, but since it was midway
through submitting
this series, thought it might be bad practice to "tack on" additional
patches to a patchset
mid-review (since it only causes an issue in some (admittedly fairly
common) use-cases)
so I was going to send it as an individual patch once (if) these were applied.
If you think that would be necessary to include for these to merge,
I'd be happy to append
it to this review. I also have another patch which adds i2c bus
recovery to the driver, but
that seems independent enough that it should be sent on its own.
> > > With this all said -- I noticed iasl prints this statement when trying
> > > to create a node with a lowercase name:
> > > "At least one lower case letter found in NameSeg, ASL is case
> > > insensitive - converting to upper case (GPIO)"
> >
> > Yes, because it should be in the upper case.
> >
> > > I wonder if this suggests that adding a call to toupper() to
> > > acpi_fwnode_get_named_child_node would be
> > > an appropriate solution for the node name casing issue....
> >
> > I dunno. You need to ask in the linux-acpi@ mailing list.
> > To me this is corner case that can't be easily solved
> > (because two different specifications treat it differently.
> >
> > You also need to ask DT people about capital letters there.
> > And my guts tell me that it's probably also carved in the spec
> > as "must be lower case" or alike.
>
> FWIW while trying to enable this, at some point I named the I2C and the
> GPIO entries "I2C0" and "GPI0" (with the number '0', not the letter
> 'o'), and it was not working as you would expect.
>
> It is commonly accepted in the ACPI world that the names do not carry
> meaning AFAICT, and so I think I agree with Andy's initial comment
> regarding using indexes, not names to also fetch the I2C and GPIO nodes.
> You can probably have a fallback mechanism for when "i2c" is not
> present, or simply check if you are in DT or not and use the names only
> if we are in DT.
More and more, after actually seeing and working with ACPI, I suspect that
you both are right. Maybe (hopefully) though, there is some unified way that can
be made to do this, so that individual drivers won't have to directly code for /
be aware of the differences in the firmware languages (at least, that seemed
to be the intent of the fw_node/device api in the first place). Maybe a
`device_get_child_by_name_or_index` (terribly long name) sort of function
might fill in that gap?
I plan to send an email asking this question more generically to ACPI & DT folks
as Andy suggested, so hopefully there will be some ideas.
>
> Thanks a lot to both of you, this will be tremendously helpful to me.
>
> Cheers,
> Benjamin
>
Thanks for testing this out! Glad that ACPI support ended up being worked into
this after all :)
