Hi Dmitry Torokhov, Thanks for the feedback. > Subject: Re: [PATCH v2 1/2] Input: exc3000 - Simplify probe() > > On Mon, Jul 17, 2023 at 06:45:27PM +0000, Biju Das wrote: > > Hi Dmitry, > > > > > Subject: Re: [PATCH v2 1/2] Input: exc3000 - Simplify probe() > > > > > > On Mon, Jul 17, 2023 at 07:15:50PM +0100, Mark Brown wrote: > > > > On Mon, Jul 17, 2023 at 04:35:02PM +0000, Biju Das wrote: > > > > > > > > > The .device_get_match_data callbacks are missing for I2C and SPI > > > > > bus > > > subsystems. > > > > > Can you please throw some lights on this? > > > > > > > > It's the first time I've ever heard of that callback, I don't know > > > > why whoever added it wouldn't have done those buses in particular > > > > or if it just didn't happen. Try adding it and if it works send > the patches? > > > > > > I think there is a disconnect. Right now device_get_match_data > > > callbacks are part of fwnode_operations. I was proposing to add > > > another optional device_get_match_data callback to 'struct bus_type' > > > to allow individual buses control how match data is handled, before > > > (or after) jumping into the fwnode-backed device_get_match_data > callbacks. > > > > That is what implemented here [1] and [2] right? [1] https://elixir.bootlin.com/linux/v6.5-rc2/source/drivers/spi/spi.c#L364 [2] https://elixir.bootlin.com/linux/v6.5-rc2/source/drivers/i2c/i2c-core-base.c#L117 > > > > > > First it check for fwnode-backed device_get_match_data callbacks and > > Fallback is bus-type based match. > > > > Looks like you are proposing to unify [1] and [2] and you want the > > logic to be other way around. ie, first bus-type match, then > > fwnode-backed callbacks? > > > > I do not have a strong preference for the ordering, i.e. I think it is > perfectly fine to do the generic fwnode-based lookup and if there is no > match have bus method called as a fallback, That involves a bit of work. const void *device_get_match_data(const struct device *dev); const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id, const struct i2c_client *client); const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev); Basically, the bus-client driver(such as exc3000) needs to pass struct device and device_get_match_data after generic fwnode-based lookup, needs to find the bus type based on struct device and call a new generic void* bus_get_match_data(void*) callback, so that each bus interface can do a match. I am not sure, is this proposal acceptable to wider people?? > but I do not want driver > writers to learn about multiple <bus-prefix>_get_match_data() > implementations, I would prefer if they could call > device_get_match_data() and the right thing happened in all cases. The driver is bus specific. So I don't know, why you want to be it generic. If it is i2c client, like other I2C api call the bus-subsystem api for match_data. Similarly, if it is spi client, do the same. Cheers, Biju
