On Saturday 22 June 2024 16:20:15 Pali Rohár wrote:
> > >> + {
> > >> + .matches = {
> > >> + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
> > >> + DMI_MATCH(DMI_PRODUCT_NAME, "XPS 15 7590"),
> > >> + },
> > >> + .driver_data = (void *)0x29L,
> > >
> > > At least for me, casting i2c address to LONG and then to pointer looks
> > > very strange. If I look at this code without knowing what the number
> > > 0x29 means I would not figure out that expression "(void *)0x29L" is i2c
> > > address.
> > >
> > > Is not there a better way to write i2c address? E.g. ".i2c_addr = 0x29"
> > > instead of ".something = (void *)0x29L" to make it readable?
> >
> > struct dmi_system_id is an existing structure and we cannot just go adding
> > fields to it. driver_data is intended to tie driver specific data to
> > each DMI match, often pointing to some struct, so it is a void *, but
>
> Yes, I know it.
>
> > in this case we only need a single integer, so we store that in the
> > pointer. That is is the address becomes obvious when looking at the code
> > which consumes the data.
>
> Ok, this makes sense. Anyway, is explicit void* cast and L suffix
> required?
I have checked compilers and L suffix is not needed. No error or warning
is generated without L.
Explicit cast is needed as without it compiler generates warning.
