On 31.05.24 17:08, Sebastian Reichel wrote:
Hi,

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).

Greetings,

-- Sebastian

Sebastian Reichel (5):
   usb: tcpm: add core framework
   usb: tcpm: fusb302: add driver
   board: rock5b-rk3588: add USB-C controller support
   board: rock5b-rk3588: enable USB-C in operating system
   MAINTAINERS: add TCPM section


I successfully tested this series on top of v2024.07-rc3.

Tested-by: Soeren Moch <[email protected]>



The highest possible USB PD mode of my power supply is negotiated
as desired:

U-Boot 2024.07-rc3-00005-ge829b94820 (Jun 01 2024 - 17:49:07 +0200)





Model: Radxa ROCK 5 Model B


DRAM:  8 GiB


Core:  355 devices, 33 uclasses, devicetree: separate


MMC:   mmc@fe2c0000: 1, mmc@fe2d0000: 2, mmc@fe2e0000: 0


Loading Environment from nowhere... OK


In:    serial@feb50000


Out:   serial@feb50000


Err:   serial@feb50000


Model: Radxa ROCK 5 Model B


Net:   No ethernet found.


Hit any key to stop autoboot:  0


=> tcpm list


| Name                            | Parent name         | Parent uclass
@ seq

| usb-typec@22                    | i2c@feac0000        | i2c @ 4 |
status: 0

=> tcpm dev usb-typec@22


dev: 0 @ usb-typec@22


=> tcpm info


TCPM State: SNK_READY


Voltage:    12.000 V


Current:     2.500 A


=>

Thanks,
Soeren

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