On Wed, Aug 09, 2023 at 06:25:51PM +0100, Jonathan Cameron wrote: > On Tue, 8 Aug 2023 15:18:52 +0300 > Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote: > > On Mon, Aug 07, 2023 at 01:37:12PM -0700, Dmitry Torokhov wrote: > > > On Mon, Aug 07, 2023 at 05:54:07PM +0300, Andy Shevchenko wrote: > > > > On Sun, Aug 06, 2023 at 02:29:50PM +0100, Jonathan Cameron wrote: > > > > > On Sat, 5 Aug 2023 17:42:21 +0000 > > > > > Biju Das <biju.das.jz@xxxxxxxxxxxxxx> wrote: > > > > > > > On Fri, 4 Aug 2023 17:17:24 +0100 > > > > > > > Biju Das <biju.das.jz@xxxxxxxxxxxxxx> wrote: ... > > > > > > + * Besides the fact that some drivers abuse the device ID driver_data type > > > > > > + * and claim it to be integer, for the bus specific ID tables the driver_data > > > > > > + * may be defined as kernel_ulong_t. For these tables 0 is a valid response, > > > > > > + * but not for this function. It's recommended to convert those either to avoid > > > > > > + * 0 or use a real pointer to the predefined driver data. > > > > > > > > > We still need to maintain consistency across the two tables, which > > > > > is a stronger requirement than avoiding 0. > > > > > > > > True. Any suggestion how to amend the above comment? Because the documentation > > > > makes sense on its own (may be split from the series?). > > > > > > > > > Some drivers already do that by forcing the enum used to start at 1 which > > > > > doesn't solver the different data types issue. > > > > > > > > And some maintainers do not want to see non-enum values in i2c ID table. > > > > *Shrug*. > > > > > > So in legacy ID lookup path we can safely assume that values below 4096 > > > are scalars and return NULL from the new device_get_match_data(). This > > > way current drivers using the values as indices or doing direct > > > comparisons against them can continue doing manual look up and using > > > them as they see fit. And we can convert the drivers at our leisure. > > > > It's a good idea, but I believe will be received as hack. > > But why not to try? We indeed have an error pointers for the last page > > and NULL (which is only up to 16 IIRC) and reserved space in the first > > page. To be more robust I would check all enums that are being used > > in I2C ID tables for maximum value and if that is less than 16, use > > ZERO_OR_NULL_PTR() instead of custom stuff. > > > See iio/adc/max1363 example that has 37ish. > > Could tidy that one up first and hopefully not find any others that > are in subsystems not keen on the move away from enums. Oh, yep, this needs a treewide audit and fixes around before going further. As you said. -- With Best Regards, Andy Shevchenko
