On 11/7/22 13:48, Luca Ceresoli wrote: > Hi Tomi, All, > > On Tue, 1 Nov 2022 15:20:24 +0200 > Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx> wrote: >> >> 2) >> If I suggested adding an i2c-bus fwnode parameter to >> i2c_mux_add_adapter(), and the i2c-bus might be under some other device, >> I think the reception could be quite negative (and I would agree). For >> this reason I'm not very happy with the i2c-atr and using it with >> FPDLink. >> >> In fact, I'm thinking that it might be better to just drop the i2c-atr >> driver, and add the support directly to the FPDlink drivers. But that >> could mean possibly duplicating the same code for other deser/ser >> architectures, so I have kept the i2c-atr driver for now. > > Indeed I think the ROHM serdes chips do have an address translation > feature that works pretty much like the TI ones, and the ATR should be > cleanly reusable across the two brands. The ATR code might be > simplified to just provide helpers for common code maybe, but I'd > rather avoid code duplication. I tend to agree with Luca on keeping the I2C-atr a re-usable generic code. The reason why I did not (yet) bring this (or other concerns) up is that currently I don't have a permission to upstream my work for ROHM SerDes Linux drivers :( I still do discuss the decision but to be honest, I believe the chances to get my drivers upstream are getting slim. Hence I did not see it reasonable to try pushing Tomi's / Luca's work to any direction. Yet, after that being said - these SerDes devices which can combine I2C buses from multiple remote devices to one local I2C controller do bring a real need for a solution like the address translation. Thus, I would not be surprized if we saw new devices with this kind of feature. Potentially also from other vendors. So, regardless what happens with ROHM SERDESes - I (too) think we should keep the ATR as independently reusable component. Yours, -- Matti Vaittinen -- Matti Vaittinen Linux kernel developer at ROHM Semiconductors Oulu Finland ~~ When things go utterly wrong vim users can always type :help! ~~
