usb typec not doing handling in-kernel
Hi,
I'm currently trying to wrap my head around the new typec subsystem and also how to do it correctly on Rockchip rk3399 devices.
The issue (and Guenter might know quite a bit about that) is that on ChromeOS devices the embedded controller hides the whole tcpm/vdm logic from the operating system and just provides a custom interface to query things like cable state, display-port hotplug status and so on.
So right now the rk3399-typec-phy uses that extcon-based interface to get all status changes but that of course leaves out all systems directly talking to a fusb302. I did a small drawing to showcase that:
------------- ------------------
| typec-phy |----| extcon-cros-ec |\
------------- ------------------ \
| \ \
------------- \ ------------------ \ -----------
| cdn-dp | \| ????? |-----| fusb302 |
------------- ------------------ -----------So to bring everything on the same page, I guess the cros-ec extcon (drivers/extcon/extcon-usbc-cros-ec.c) should somehow use the typec functions instead of implementing an extcon? But from reading into the typec code, it somehow looks like the typec framework expects to be in control of things like altmode negotiations, or am I misreading something?
Thanks
Heiko
Quoted 22 lines · Heiko Stuebner
Hi,
I'm currently trying to wrap my head around the new typec subsystem and also how to do it correctly on Rockchip rk3399 devices.
The issue (and Guenter might know quite a bit about that) is that on ChromeOS devices the embedded controller hides the whole tcpm/vdm logic from the operating system and just provides a custom interface to query things like cable state, display-port hotplug status and so on.
So right now the rk3399-typec-phy uses that extcon-based interface to get all status changes but that of course leaves out all systems directly talking to a fusb302. I did a small drawing to showcase that:
------------- ------------------ | typec-phy |----| extcon-cros-ec |\ ------------- ------------------ \ | \ \ ------------- \ ------------------ \ ----------- | cdn-dp | \| ????? |-----| fusb302 | ------------- ------------------ -----------
Quoted 6 lines
So to bring everything on the same page, I guess the cros-ec extcon (
drivers/extcon/extcon-usbc-cros-ec.c) should somehow use the typec functions instead of implementing an extcon? But from reading into the typec code, it somehow looks like the typec framework expects to be in control of things like altmode negotiations, or am I misreading something?
I used to have a patch for the cros-ec extcon driver which ties it into the typec subsystem. Let me see if I can dig it up.
Guenter
A message that is not in the archive (sent off-list or not yet received): 6e3e7449-1957-e98d-c186-97d960e06c09-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org
Hi Guenter,
Am Montag, 13. August 2018, 14:29:15 CEST schrieb Guenter Roeck:
Quoted 23 lines · Heiko Stuebner
Quoted 22 lines
Hi,
I'm currently trying to wrap my head around the new typec subsystem and also how to do it correctly on Rockchip rk3399 devices.
The issue (and Guenter might know quite a bit about that) is that on ChromeOS devices the embedded controller hides the whole tcpm/vdm logic from the operating system and just provides a custom interface to query things like cable state, display-port hotplug status and so on.
So right now the rk3399-typec-phy uses that extcon-based interface to get all status changes but that of course leaves out all systems directly talking to a fusb302. I did a small drawing to showcase that:
------------- ------------------ | typec-phy |----| extcon-cros-ec |\ ------------- ------------------ \ | \ \ ------------- \ ------------------ \ ----------- | cdn-dp | \| ????? |-----| fusb302 | ------------- ------------------ -----------
Quoted 8 lines
Quoted 6 lines
So to bring everything on the same page, I guess the cros-ec extcon (
drivers/extcon/extcon-usbc-cros-ec.c) should somehow use the typec functions instead of implementing an extcon? But from reading into the typec code, it somehow looks like the typec framework expects to be in control of things like altmode negotiations, or am I misreading something?I used to have a patch for the cros-ec extcon driver which ties it into the typec subsystem. Let me see if I can dig it up.
were your archeological skills working in finding said old patch?
Thanks
Heiko
Quoted 32 lines · Heiko Stuebner
Hi Guenter,
Am Montag, 13. August 2018, 14:29:15 CEST schrieb Guenter Roeck:
Quoted 29 lines · Heiko Stuebner
Quoted 28 lines
Hi,
I'm currently trying to wrap my head around the new typec subsystem and also how to do it correctly on Rockchip rk3399 devices.
The issue (and Guenter might know quite a bit about that) is that on ChromeOS devices the embedded controller hides the whole tcpm/vdm logic from the operating system and just provides a custom interface to query things like cable state, display-port hotplug status and so on.
So right now the rk3399-typec-phy uses that extcon-based interface to get all status changes but that of course leaves out all systems directly talking to a fusb302. I did a small drawing to showcase that:
------------- ------------------ | typec-phy |----| extcon-cros-ec |\ ------------- ------------------ \ | \ \ ------------- \ ------------------ \ ----------- | cdn-dp | \| ????? |-----| fusb302 | ------------- ------------------ -----------So to bring everything on the same page, I guess the cros-ec extcon (
drivers/extcon/extcon-usbc-cros-ec.c) should somehow use the typec functions instead of implementing an extcon? But from reading into the typec code, it somehow looks like the typec framework expects to be in control of things like altmode negotiations, or am I misreading something?
Quoted 5 lines
Quoted 2 lines
I used to have a patch for the cros-ec extcon driver which ties it into the typec subsystem. Let me see if I can dig it up.
were your archeological skills working in finding said old patch?
Not very well :-(
Guenter
Hi Heiko,
Quoted 22 lines · Heiko Stuebner
Hi,
I'm currently trying to wrap my head around the new typec subsystem and also how to do it correctly on Rockchip rk3399 devices.
The issue (and Guenter might know quite a bit about that) is that on ChromeOS devices the embedded controller hides the whole tcpm/vdm logic from the operating system and just provides a custom interface to query things like cable state, display-port hotplug status and so on.
So right now the rk3399-typec-phy uses that extcon-based interface to get all status changes but that of course leaves out all systems directly talking to a fusb302. I did a small drawing to showcase that:
------------- ------------------ | typec-phy |----| extcon-cros-ec |\ ------------- ------------------ \ | \ \ ------------- \ ------------------ \ ----------- | cdn-dp | \| ????? |-----| fusb302 | ------------- ------------------ -----------
Quoted 3 lines
So to bring everything on the same page, I guess the cros-ec extcon (
drivers/extcon/extcon-usbc-cros-ec.c) should somehow use the typec functions instead of implementing an extcon?
I don't think the two necessary exclude each other. You can continue to register the extcon device and use it for communication with the phy driver, and also register your Type-C port(s), partners, and optionally the port and partner alternate modes. I guess Guenter has patches for that already?
It looks to me like that phy driver could just register a Type-C switch for the orientation, and mux for the mode. Those seem to be the only details the driver needs from extcon-usbc-cros-ec.
Quoted 3 lines
But from reading into the typec code, it somehow looks like the typec framework expects to be in control of things like altmode negotiations, or am I misreading something?
The alternate mode drivers will assume they are in control of the negotiation with the partner, but note that you will not always need them. The rest of the code in the framework doesn't expect to be in control of the communication.
If the EC (or some other microcontroller) firmware is taking care of the actual entering and configuring of the alternate modes, the port driver (so extcon-usbc-cros-ec in your case) will need to "emulate" the VDM communication if the alt mode drivers need to be used, and that means they need to do so with every supported alternate mode separately.
Of course if the details that for example the DisplayPort alt mode driver supplies to the user space is not relevant on your system, and there is no requirement to allow the user to be able to reconfigure the DisplayPort alt mode (note: you will also be unable to exit the mode from sysfs in this case), you can still register the partner alt mode device and simply allow the binding to the driver fail, or don't register the partner alt modes with the USB Type-C framework at all.
I've prepared patches for the ucsi driver that add displayport alt mode support to it. UCSI is just a standardised firmware interface for USB Type-C conncetors, so the situation is exactly the same as with extcon-usbc-cros-ec. I was planning to send the patches out for review after next -rc1, but I guess I could send a RFC already. With UCSI we do have a requirement to allow the user to reconfigure the DisplayPort alternate mode if needed.
Br,
Signature · 1 line
heikki
A message that is not in the archive (sent off-list or not yet received): 20180813133637.GA25757-FZxXFokcWpatqXYlAKuG4QC/[email protected]
Hi Heikki,
Am Montag, 13. August 2018, 15:36:37 CEST schrieb Heikki Krogerus:
Quoted 25 lines · Heiko Stuebner
Quoted 20 lines
I'm currently trying to wrap my head around the new typec subsystem and also how to do it correctly on Rockchip rk3399 devices.
The issue (and Guenter might know quite a bit about that) is that on ChromeOS devices the embedded controller hides the whole tcpm/vdm logic from the operating system and just provides a custom interface to query things like cable state, display-port hotplug status and so on.
So right now the rk3399-typec-phy uses that extcon-based interface to get all status changes but that of course leaves out all systems directly talking to a fusb302. I did a small drawing to showcase that:
------------- ------------------ | typec-phy |----| extcon-cros-ec |\ ------------- ------------------ \ | \ \ ------------- \ ------------------ \ ----------- | cdn-dp | \| ????? |-----| fusb302 | ------------- ------------------ -----------Quoted 3 lines
So to bring everything on the same page, I guess the cros-ec extcon (
drivers/extcon/extcon-usbc-cros-ec.c) should somehow use the typec functions instead of implementing an extcon?
Quoted 5 lines
I don't think the two necessary exclude each other. You can continue to register the extcon device and use it for communication with the phy driver, and also register your Type-C port(s), partners, and optionally the port and partner alternate modes. I guess Guenter has patches for that already?
The issue is less with the working ChromeOS devices :-) .
What I'm trying to fit in there are all the other boards directly talking to a fusb302 via i2c and needing to do all these negotiations.
So the rockchip typec phy would need to handle both cases. In the Rockchip vendor kernel they bolted the extcon export onto their fusb302 driver but I don't think that is really future proof ;-) .
Hence the easiest way would probably be to have everything use the newer typec APIs and not try to make the Rockchip typec-phy handle both cases.
And looking at Guenters mail, it seems like he had the same idea as well in the past, so I'll hope for his archeology-skills :-) .
Quoted 3 lines
It looks to me like that phy driver could just register a Type-C switch for the orientation, and mux for the mode. Those seem to be the only details the driver needs from extcon-usbc-cros-ec.
Looks like it - I'm still trying to find my way through the typec subsystem though.
Quoted 16 lines
Quoted 3 lines
But from reading into the typec code, it somehow looks like the typec framework expects to be in control of things like altmode negotiations, or am I misreading something?
The alternate mode drivers will assume they are in control of the negotiation with the partner, but note that you will not always need them. The rest of the code in the framework doesn't expect to be in control of the communication.
If the EC (or some other microcontroller) firmware is taking care of the actual entering and configuring of the alternate modes, the port driver (so extcon-usbc-cros-ec in your case) will need to "emulate" the VDM communication if the alt mode drivers need to be used, and that means they need to do so with every supported alternate mode separately.
Quoted 7 lines
Of course if the details that for example the DisplayPort alt mode driver supplies to the user space is not relevant on your system, and there is no requirement to allow the user to be able to reconfigure the DisplayPort alt mode (note: you will also be unable to exit the mode from sysfs in this case), you can still register the partner alt mode device and simply allow the binding to the driver fail, or don't register the partner alt modes with the USB Type-C framework at all.
As said above, I'm mainly trying to make the typec framework usable for all the rk3399 boards using the "standard" setup of talking directly to the fusb302 but of course want to pull the cros-ec special case along, to not create to much overhead anywhere.
Thankfully it is really only the DisplayPort Alt Mode that is supported on the rk3399.
While the extcon driver doesn't seem to use it right now, looking through the ec-commands shows that muxes, roles etc seem configurable from the host side.
Quoted 7 lines
I've prepared patches for the ucsi driver that add displayport alt mode support to it. UCSI is just a standardised firmware interface for USB Type-C conncetors, so the situation is exactly the same as with extcon-usbc-cros-ec. I was planning to send the patches out for review after next -rc1, but I guess I could send a RFC already. With UCSI we do have a requirement to allow the user to reconfigure the DisplayPort alternate mode if needed.
That might be helpful. But you don't really have to hurry that much. -rc1 isn't that far away and I do have enough individual projects to keep me busy ;-) .
Especially also as the device_connection stuff does seem to still miss graph-parsing [0] to connect my dt-stuff together, there is no really hurry.
Thanks
Heiko
Hi,
Quoted 32 lines · Heiko Stuebner
Am Montag, 13. August 2018, 15:36:37 CEST schrieb Heikki Krogerus:
Quoted 25 lines · Heiko Stuebner
Quoted 20 lines
I'm currently trying to wrap my head around the new typec subsystem and also how to do it correctly on Rockchip rk3399 devices.
The issue (and Guenter might know quite a bit about that) is that on ChromeOS devices the embedded controller hides the whole tcpm/vdm logic from the operating system and just provides a custom interface to query things like cable state, display-port hotplug status and so on.
So right now the rk3399-typec-phy uses that extcon-based interface to get all status changes but that of course leaves out all systems directly talking to a fusb302. I did a small drawing to showcase that:
------------- ------------------ | typec-phy |----| extcon-cros-ec |\ ------------- ------------------ \ | \ \ ------------- \ ------------------ \ ----------- | cdn-dp | \| ????? |-----| fusb302 | ------------- ------------------ -----------Quoted 3 lines
So to bring everything on the same page, I guess the cros-ec extcon (
drivers/extcon/extcon-usbc-cros-ec.c) should somehow use the typec functions instead of implementing an extcon?Quoted 5 lines
I don't think the two necessary exclude each other. You can continue to register the extcon device and use it for communication with the phy driver, and also register your Type-C port(s), partners, and optionally the port and partner alternate modes. I guess Guenter has patches for that already?
Quoted 4 lines
The issue is less with the working ChromeOS devices :-) .
What I'm trying to fit in there are all the other boards directly talking to a fusb302 via i2c and needing to do all these negotiations.
Ah, OK. Now I get it.
Quoted 64 lines
So the rockchip typec phy would need to handle both cases. In the Rockchip vendor kernel they bolted the extcon export onto their fusb302 driver but I don't think that is really future proof ;-) .
Hence the easiest way would probably be to have everything use the newer typec APIs and not try to make the Rockchip typec-phy handle both cases.
And looking at Guenters mail, it seems like he had the same idea as well in the past, so I'll hope for his archeology-skills :-) .
Quoted 3 lines
It looks to me like that phy driver could just register a Type-C switch for the orientation, and mux for the mode. Those seem to be the only details the driver needs from extcon-usbc-cros-ec.
Looks like it - I'm still trying to find my way through the typec subsystem though.
Quoted 16 lines
Quoted 3 lines
But from reading into the typec code, it somehow looks like the typec framework expects to be in control of things like altmode negotiations, or am I misreading something?
The alternate mode drivers will assume they are in control of the negotiation with the partner, but note that you will not always need them. The rest of the code in the framework doesn't expect to be in control of the communication.
If the EC (or some other microcontroller) firmware is taking care of the actual entering and configuring of the alternate modes, the port driver (so extcon-usbc-cros-ec in your case) will need to "emulate" the VDM communication if the alt mode drivers need to be used, and that means they need to do so with every supported alternate mode separately.
Quoted 7 lines
Of course if the details that for example the DisplayPort alt mode driver supplies to the user space is not relevant on your system, and there is no requirement to allow the user to be able to reconfigure the DisplayPort alt mode (note: you will also be unable to exit the mode from sysfs in this case), you can still register the partner alt mode device and simply allow the binding to the driver fail, or don't register the partner alt modes with the USB Type-C framework at all.
As said above, I'm mainly trying to make the typec framework usable for all the rk3399 boards using the "standard" setup of talking directly to the fusb302 but of course want to pull the cros-ec special case along, to not create to much overhead anywhere.
Thankfully it is really only the DisplayPort Alt Mode that is supported on the rk3399.
While the extcon driver doesn't seem to use it right now, looking through the ec-commands shows that muxes, roles etc seem configurable from the host side.
Quoted 7 lines
I've prepared patches for the ucsi driver that add displayport alt mode support to it. UCSI is just a standardised firmware interface for USB Type-C conncetors, so the situation is exactly the same as with extcon-usbc-cros-ec. I was planning to send the patches out for review after next -rc1, but I guess I could send a RFC already. With UCSI we do have a requirement to allow the user to reconfigure the DisplayPort alternate mode if needed.
Quoted 7 lines
That might be helpful. But you don't really have to hurry that much. -rc1 isn't that far away and I do have enough individual projects to keep me busy ;-) .
Especially also as the
device_connectionstuff does seem to still miss graph-parsing [0] to connect my dt-stuff together, there is no really hurry.
True, the graph parsing is indeed missing from that API. I'll see if I can propose something for that at one point (soon hopefully).
Cheers,
Signature · 1 line
heikki
A message that is not in the archive (sent off-list or not yet received): 20180815144636.GB25757-FZxXFokcWpatqXYlAKuG4QC/[email protected]
Hi,
Am Mittwoch, 15. August 2018, 16:46:36 CEST schrieb Heikki Krogerus:
Quoted 108 lines · Heiko Stuebner
Quoted 32 lines
Am Montag, 13. August 2018, 15:36:37 CEST schrieb Heikki Krogerus:
Quoted 25 lines
On Mon, Aug 13, 2018 at 12:36:55PM +0200, Heiko Stuebner wrote:ß
Quoted 20 lines
I'm currently trying to wrap my head around the new typec subsystem and also how to do it correctly on Rockchip rk3399 devices.
The issue (and Guenter might know quite a bit about that) is that on ChromeOS devices the embedded controller hides the whole tcpm/vdm logic from the operating system and just provides a custom interface to query things like cable state, display-port hotplug status and so on.
So right now the rk3399-typec-phy uses that extcon-based interface to get all status changes but that of course leaves out all systems directly talking to a fusb302. I did a small drawing to showcase that:
------------- ------------------ | typec-phy |----| extcon-cros-ec |\ ------------- ------------------ \ | \ \ ------------- \ ------------------ \ ----------- | cdn-dp | \| ????? |-----| fusb302 | ------------- ------------------ -----------Quoted 3 lines
So to bring everything on the same page, I guess the cros-ec extcon (
drivers/extcon/extcon-usbc-cros-ec.c) should somehow use the typec functions instead of implementing an extcon?Quoted 5 lines
I don't think the two necessary exclude each other. You can continue to register the extcon device and use it for communication with the phy driver, and also register your Type-C port(s), partners, and optionally the port and partner alternate modes. I guess Guenter has patches for that already?
Quoted 4 lines
The issue is less with the working ChromeOS devices :-) .
What I'm trying to fit in there are all the other boards directly talking to a fusb302 via i2c and needing to do all these negotiations.
Ah, OK. Now I get it.
Quoted 68 lines
So the rockchip typec phy would need to handle both cases. In the Rockchip vendor kernel they bolted the extcon export onto their fusb302 driver but I don't think that is really future proof ;-) .
Hence the easiest way would probably be to have everything use the newer typec APIs and not try to make the Rockchip typec-phy handle both cases.
And looking at Guenters mail, it seems like he had the same idea as well in the past, so I'll hope for his archeology-skills :-) .
Quoted 3 lines
It looks to me like that phy driver could just register a Type-C switch for the orientation, and mux for the mode. Those seem to be the only details the driver needs from extcon-usbc-cros-ec.
Looks like it - I'm still trying to find my way through the typec subsystem though.
Quoted 16 lines
Quoted 3 lines
But from reading into the typec code, it somehow looks like the typec framework expects to be in control of things like altmode negotiations, or am I misreading something?
The alternate mode drivers will assume they are in control of the negotiation with the partner, but note that you will not always need them. The rest of the code in the framework doesn't expect to be in control of the communication.
If the EC (or some other microcontroller) firmware is taking care of the actual entering and configuring of the alternate modes, the port driver (so extcon-usbc-cros-ec in your case) will need to "emulate" the VDM communication if the alt mode drivers need to be used, and that means they need to do so with every supported alternate mode separately.
Quoted 7 lines
Of course if the details that for example the DisplayPort alt mode driver supplies to the user space is not relevant on your system, and there is no requirement to allow the user to be able to reconfigure the DisplayPort alt mode (note: you will also be unable to exit the mode from sysfs in this case), you can still register the partner alt mode device and simply allow the binding to the driver fail, or don't register the partner alt modes with the USB Type-C framework at all.
As said above, I'm mainly trying to make the typec framework usable for all the rk3399 boards using the "standard" setup of talking directly to the fusb302 but of course want to pull the cros-ec special case along, to not create to much overhead anywhere.
Thankfully it is really only the DisplayPort Alt Mode that is supported on the rk3399.
While the extcon driver doesn't seem to use it right now, looking through the ec-commands shows that muxes, roles etc seem configurable from the host side.
Quoted 7 lines
I've prepared patches for the ucsi driver that add displayport alt mode support to it. UCSI is just a standardised firmware interface for USB Type-C conncetors, so the situation is exactly the same as with extcon-usbc-cros-ec. I was planning to send the patches out for review after next -rc1, but I guess I could send a RFC already. With UCSI we do have a requirement to allow the user to reconfigure the DisplayPort alternate mode if needed.
That might be helpful. But you don't really have to hurry that much. -rc1 isn't that far away and I do have enough individual projects to keep me busy ;-) .
Quoted 6 lines
Quoted 3 lines
Especially also as the
device_connectionstuff does seem to still miss graph-parsing [0] to connect my dt-stuff together, there is no really hurry.True, the graph parsing is indeed missing from that API. I'll see if I can propose something for that at one point (soon hopefully).
as I'm just sitting next to Guenter at ELCE talking about that type-c stuff, did you manage that graph parsing patch we talked about two months ago ;-) ?
Thanks
Heiko
Hi guys,
Quoted 6 lines · Heiko Stuebner
Quoted 2 lines
True, the graph parsing is indeed missing from that API. I'll see if I can propose something for that at one point (soon hopefully).
as I'm just sitting next to Guenter at ELCE talking about that type-c stuff, did you manage that graph parsing patch we talked about two months ago ;-) ?
To be honest, I've forgotten about this completely, sorry. I did prepare the patch for this, but I never managed to test it.
I'll send the patch as RFC right a way. Sorry for the delay.
Enjoy the conference!
Signature · 1 line
heikki
Hello everyone,
Enric was looking recently at some of this to get gadget mode working.
I drew this diagram around that time to help explain how things are hooked up on the rk3399 chromebooks. I hope it might be useful for this discussion.
https://sites.google.com/a/chromium.org/dev/chromium-os/type-c-on-rk3399-chromebooks
Some things to note (which may or may not be already know in here):
* CC lines on the rk3399 are not connected to anything, we have an external TCPC
* OTG_ID pin not connected to anything
* rk3399 doesn't do much in terms of negotiating type C things or charging, everything must be handled by the EC (since such things might happen when the rk3399 is off or asleep). Instead the EC communicates most of that state via the SPI lines (hence cros-ec driver).
Alexandru Stan (amstan)
Quoted 39 lines · Heiko Stuebner
Hi,
I'm currently trying to wrap my head around the new typec subsystem and also how to do it correctly on Rockchip rk3399 devices.
The issue (and Guenter might know quite a bit about that) is that on ChromeOS devices the embedded controller hides the whole tcpm/vdm logic from the operating system and just provides a custom interface to query things like cable state, display-port hotplug status and so on.
So right now the rk3399-typec-phy uses that extcon-based interface to get all status changes but that of course leaves out all systems directly talking to a fusb302. I did a small drawing to showcase that:
------------- ------------------ | typec-phy |----| extcon-cros-ec |\ ------------- ------------------ \ | \ \ ------------- \ ------------------ \ ----------- | cdn-dp | \| ????? |-----| fusb302 | ------------- ------------------ -----------So to bring everything on the same page, I guess the cros-ec extcon (
drivers/extcon/extcon-usbc-cros-ec.c) should somehow use the typec functions instead of implementing an extcon? But from reading into the typec code, it somehow looks like the typec framework expects to be in control of things like altmode negotiations, or am I misreading something?Thanks
Heiko_______________________________________________
Linux-rockchip mailing list [email protected]
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