[PATCH v6 0/6] FUSB302 USB-C controller support

[Sebastian Reichel]

Hi Jonas,

On Wed, Sep 18, 2024 at 09:56:35AM GMT, Jonas Karlman wrote:
> On 2024-09-05 17:08, Sebastian Reichel wrote:
> > On ROCK 5B power is usually supplied via it's USB-C port. This port has the
> > data lines connected to RK3588, VBUS connected to the input regulator and
> > CC pins connected to FUSB302. FUSB302 is a USB-C controller, which can be
> > accessed via I2C from RK3588. The USB-C controller is needed to figure out
> > the USB-C cable orientation, but also to do USB PD communication. Thus it
> > would be great to enable support for it in the operating system.
> > 
> > But the USB-PD specification requires, that a device reacts to USB-PD messages
> > send by the power-supply within around 5 seconds. If that does not happen the
> > power-supply assumes, that the device does not support USB-PD. If a device
> > later starts sending USB-PD messages it is considered an error, which is solved
> > by doing a hard reset. A USB-PD hard reset means, that all supply voltages are
> > removed for a short period of time. For boards, which are solely powered
> > through their USB-C port, like the Radxa Rock 5B, this results in an machine
> > reset. This is currently worked around by not describing the FUSB302 in the
> > kernel DT, so nothing will ever speak USB-PD on the Rock 5B. This means
> > 
> > 1. the USB-C port cannot be used at all
> > 2. the board will be running via fallback supply, which provides limited
> >    power capabilities
> > 
> > In order to avoid the hard reset, this adds FUSB302 support to U-Boot, so
> > that we react to the power-supply's queries in time. The code, which is
> > originally from the Linux kernel, consists of two parts:
> > 
> > 1. the tcpm state machine, which implements the Type C port manager state
> >    machine as described in the USB PD specification
> > 2. the fusb302 driver, which knows about specific registers
> > 
> > Especially the first part has been heavily modified compared to the
> > kernel, which makes use of multiple delayed works and threads. For this
> > I used a priorly ported version from Rockchip, removed their hacks and
> > any states not necessary in U-Boot (e.g. audio accessory support).
> > 
> > This version has been tested on Radxa Rock 5B using the open source TF-A
> > (patches recently got merged into master branch) using the following power
> > supplies:
> > 
> >  * non PD capable (reports 5V 0A)
> >  * RavPower 90W
> >  * UGREEN 100W
> >  * Anker 45W
> >  * RavPower PB
> > 
> 
> [snip]
> 
> This series look good and works great on my ROCK 5B, tested using two
> different PD capable power supplies, so this entire series is:
> 
> Reviewed-by: Jonas Karlman <jonas at kwiboo.se>

Thanks.

> I did notice that trying to hook up the ROCK 5B from my computer to use
> UMS in U-Boot there is a slight delay at boot and following is shown:
> 
>   fusb302 usb-typec at 22: TCPM: PD transmit data failed: -110
> 
> I suspect this work as intended, so nothing blocking.

Yes. These potential delays are the reason why I only wanted to
enable this for affected boards.

I suppose we can try to get rid of the error message for the case
of not having PD at all. Note, that a standard compliant USB port
(limited to 500mA [USB2] or 900mA [USB3]) is not good enough to
power the Rock 5B since cpufreq got enabled. the Rock 5Bs in
Collabora's KernelCI farm were originally powered through a USB
hub and the hub powered the port off during boot after applying
the cpufreq patches. So the error might be useful to understand
why there are boot issues.

Greetings,

-- Sebastian
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