Re: [PATCH] USB: serial: pl2303: Modify the detection method of PL2303HXN (TYPE_HXN)

[Johan Hovold <johan@kernel.org>]

On Mon, Jun 20, 2022 at 06:51:58PM +0800, Charles Yeh wrote:
> > > The setting value of bcdUSB & bcdDevice of PL2303TA is the same as the
> > > setting value of bcdUSB & bcdDevice of a certain chip of PL2303HXN
> >
> > Which ones would that be?
> 
> PL2303GT_R4 (chip version: v4) is the same as PL2303TA.

[...]

> > > The setting value of bcdUSB & bcdDevice of PL2303TB is the same as the
> > > setting value of bcdUSB & bcdDevice of a certain chip of PL2303HXN
> >
> > Same question here.
> 
> PL2303GE_R4 (chip version: v4) is the same as PL2303TB.

Thanks for the details.

> > Could you provide a list of the bcdDevice you use for the various HXN
> > types instead?
> 
> I also hope to have a complete list of all HXN versions..
> But it is difficult.. I use PL2303GT as an example.
> PL2303GT is currently divided into PL2303GT_R4 / PL2303GT_R5 / PL2303GT_R5+
> 
> PL2303GT_R4  : idProduct : 0x23C3, bcdDevice: 0x0300
> PL2303GT_R5  : idProduct : 0x23C3, bcdDevice: 0x0305
> PL2303GT_R5+ : idProduct : 0x23A3, bcdDevice: 0x0305
> 
> The above three kinds of PL2303GT are currently available in the market.

Ok, but the above could be handled with two entries or if needed we can
just check the major number (i.e. the MSB, 0x03)?

Do the other types follow a similar pattern?

So far I've gathered that

	0x100	GC
	0x105	GC
	0x300	GT / TA
	0x305	GT
	0x405	GL
	0x500	GE / TB
	0x605	GS

So it look like we could use the major version number.

Anything more we need to add to the above list?

> From the bcdUSB & bcdDevice of PL2303GT_R4, it is the same as PL2303TA.
> So it needs to be checked again with hx_status check.

Right, the 0x300 and 0x500 need special handling.

> As mentioned earlier, some HXNs are currently on sale,
> and some HXN versions are coming out (bcdDevice will have other settings),
> HXN cannot use bcdDevice to determine the type one by one.

Surely you have way to determine the types since they have different
features. Are you not using bcdDevice for this for that other OS?

Johan