Hi Anand, On Mon, Mar 03, 2025 at 01:08:24PM +0530, Anand Moon wrote: > On Sat, 1 Mar 2025 at 23:41, Peter Robinson <pbrobin...@gmail.com> wrote: > > On Thu, 27 Feb 2025 at 06:01, Anand Moon <linux.am...@gmail.com> wrote: > >> On Thu, 27 Feb 2025 at 00:15, Sebastian Reichel > >> <sebastian.reic...@collabora.com> wrote: > >> > > >> > Hi, > >> > > >> > I have a couple of fixes/improvements for the TCPM code. Three are fixing > >> > actual problems I noticed on the Rock 5B, which prevented booting up the > >> > system. One of them simply adds an error print before potentially > >> > committing > >> > hara-kiri by triggering a hard reset, which helps people understanding > >> > why their boards reset themself in case there are more problems. I've > >> > recently added the same print to the kernel TCPM code. > >> > > >> I have encountered issues with the Raspberry Pi Type C power > >> supply on a few occasions. Thanks for these changes, but it > >> dose not resolve the issue completely.
I don't promise fixing all issues with this series. USB-PD is super complex. This series improves things and shouldn't have any regressions. It also helps with debugging further issues by having the extra print. > > I don't believe the RPi Type-C power supply supports power delivery. > > RPi 5 Type-C power supply is generally compatible with the Rock 5B > for daily use. I also have the Radxa 65W official Type-C power > supply for the Radxa Rock 5B board. I was checking the connection > messages with different power sources. > > >> Do you have plans to add a device tree node for this board? > > > > For which board? > > Radxa Rock 5B and Rock 5B+ indeed have a versatile USB Type-C port > that can be used both as a display port and a power source. > > During my investigation, I discovered that the Type-C port uses > the FCS,FUSB302 the driver instead of the TCPM driver. The > FUSB302 driver is specifically designed for USB Power Delivery > (USB PD) and supports various power delivery protocols. The fusb302 driver uses the TCPM framework. TCPM means "Type C Port Manager". The chip is not autonomous (like some other USB-PD chips). Without a driver telling it, what messages should be exchanged, it will stay quiet. TCPM implements the huge USB-PD state machine, which knows when a specific messages is expected or needs to be send. The remote side (i.e. the power-supply) has a similar state machine implemented. Ending up in a bad state in the state machine results in the system trying to do a hard reset to go back to the start. A hard reset involves removing the supply voltage and thus kills boards like the Rock 5B. To avoid this the state machine must be tweaked. That's why FUSB302 is not really mentioned here - the driver is passing the messages correctly. TCPM is the relevant bit, as that contains the state machine. > As of now, I don't have a Type-C power source monitor to test the > feature You can also get debug information from the Rock 5B itself. But then you should make sure it has a backup power-supply (e.g. PoE or via the GPIO header), so that it does not reset itself when a USB-PD hard reset happens. Also this setup has some side-effects to the communication itself, since it affects the timings if you enable too much debug messages. Greetings, -- Sebastian
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