Em Mon, 22 Feb 2021 16:47:36 +0100 Johan Hovold <johan@xxxxxxxxxx> escreveu: > On Mon, Feb 22, 2021 at 04:27:34PM +0100, Mauro Carvalho Chehab wrote: > > Hi Johan, > > > > Em Tue, 26 Jan 2021 17:26:36 +0100 > > Johan Hovold <johan@xxxxxxxxxx> escreveu: > > > > > On Tue, Jan 26, 2021 at 09:16:04PM +0530, Manivannan Sadhasivam wrote: > > > > On Thu, Jan 21, 2021 at 11:19:24AM +0100, Johan Hovold wrote: > > > > > On Sun, Nov 22, 2020 at 10:38:20PM +0530, Manivannan Sadhasivam wrote: > > > > > > Add support for MaxLinear/Exar USB to Serial converters. This driver > > > > > > only supports XR21V141X series but it can be extended to other series > > > > > > from Exar as well in future. > > > I'm now facing an issue with this driver. I have here two different > > boards with those USB UART from MaxLinear/Exar. > > > > The first one is identical to Mani's one: > > USB_DEVICE(0x04e2, 0x1411) > > The second one is a different version of it: > > USB_DEVICE(0x04e2, 0x1424) > > > > By looking at the final driver merged at linux-next, it sounds that > > somewhere during the review of this series, it lost the priv struct, > > and the xr_probe function. It also lost support for all MaxLinear/Exar > > devices, except for just one model (04e2:1411). > > > > The original submission: > > > > https://lore.kernel.org/linux-usb/20180404070634.nhspvmxcjwfgjkcv@advantechmxl-desktop > > > > And the manufacturer's Linux driver on their website: > > > > https://www.maxlinear.com/support/design-tools/software-drivers > > > > Had support for other 12 different models of the MaxLinear/Exar USB > > UART. > > IIRC Manivannan only had access to one of these models and his original > submission (based on the patch you link to above) didn't include support > for the others. And keeping the type abstraction didn't make sense for > just one model. > > > Those are grouped into 5 different major types: > > > > + init_xr2280x_reg_map(); > > + init_xr21b142x_reg_map(); > > + init_xr21b1411_reg_map(); > > + init_xr21v141x_reg_map(); > > + > > + if ((xrusb->DeviceProduct & 0xfff0) == 0x1400) > > + memcpy(&(xrusb->reg_map), &xr2280x_reg_map, > > + sizeof(struct reg_addr_map)); > > + else if ((xrusb->DeviceProduct & 0xFFF0) == 0x1420) > > + memcpy(&(xrusb->reg_map), &xr21b142x_reg_map, > > + sizeof(struct reg_addr_map)); > > + else if (xrusb->DeviceProduct == 0x1411) > > + memcpy(&(xrusb->reg_map), &xr21b1411_reg_map, > > + sizeof(struct reg_addr_map)); > > + else if ((xrusb->DeviceProduct & 0xfff0) == 0x1410) > > + memcpy(&(xrusb->reg_map), &xr21v141x_reg_map, > > + sizeof(struct reg_addr_map)); > > + else > > + rv = -1; > > > > Note: Please don't be confused by "reg_map" name. This has nothing > > to do with Linux regmap API ;-) > > > > What happens is that different USB IDs have different values for > > each register. So, for instance, the UART enable register is set to > > either one of the following values, depending on the value of > > udev->descriptor.idProduct: > > > > xr21b140x_reg_map.uart_enable_addr = 0x00; > > xr21b1411_reg_map.uart_enable_addr = 0xc00; > > xr21v141x_reg_map.uart_enable_addr = 0x03; > > xr21b142x_reg_map.uart_enable_addr = 0x00; > > > > There are other values that depend on the probing time detection, > > based on other USB descriptors. Those set several fields at the > > priv data that would allow to properly map the registers. > > > > Also, there are 4 models that support multiple channels. On those, > > there are one pair of register get/set for each channel. > > > > - > > > > In summary, while supporting just 04e2:1411 there's no need for > > a private struct, in order to properly support the other models, > > some autodetection is needed. The best way of doing that is to > > re-add the .probe method and adding a priv struct. > > > > As I dunno why this was dropped in the first place, I'm wondering > > if it would be ok to re-introduce them. > > Sure. It was just not needed if we were only going to support one model. > > > To be clear: my main focus here is just to avoid needing to use > > Windows in order to use the serial console of the hardware with > > the 0x1424 variant ;-) > > > > I can't test the driver with the other hardware, but, IMHO, instead > > of adding a hack to support 0x1424, the better (but more painful) > > would be to re-add the auto-detection part and support for the > > other models. > > Sounds good to me. Great! I'll work on a patch and submit when done. Thanks! Mauro
