On 3/22/20 4:17 PM, Simon Glass wrote: > Hi Marek, Hi,
> On Sat, 21 Mar 2020 at 20:15, Marek Vasut <ma...@denx.de> wrote: >> >> On 3/22/20 3:08 AM, Simon Glass wrote: >>> Hi Marek, >> >> Hi, >> >>> I think at this point we've covered all the ground and mentioned the >>> pros and cons of each method, so I'll leave the discussion where it >>> is. >> >> Great, so let's remove the struct-based access from the driver and use >> regular #define REGISTER 0xoffset. > > I think any individual decision depends on the pros and cons we > outlined in our discussion. I don't have any information to suggest > that the Mediatek XHCI driver has any of the variations you talked > about in your worst-case scenarios, so I can't comment on that. I am > more concerned about this as a general rule as I feel that the > struct-based approach is generally best for U-Boot, except for the > cases you highlighted: > > - where the registers appear at different offsets in different > hardware revisions served by the same driver > - where the driver only uses a small subset of the registers and it is > not worth defining a struct to cover them all, with associated empty > regions, etc. > > Anything else? It's also very difficult to easily figure out the address of a register that's buried somewhere down in a long structure, possibly with embedded sub-structures. > This is a USB driver and you are the USB maintainer, so your decision > is OK with me. For driver model in general I feel that struct access > should be the default, but individual maintainers with strong views on > their subsystem need to have preference. Well, like I said, my experience tells me the struct approach was a big mistake in multiple places, so I would prefer macros here. -- Best regards, Marek Vasut
