> Subject: RE: [PATCH v2 1/2] Input: exc3000 - Simplify probe() > > Hi Dmitry, > > Thanks for the feedback. > > > Subject: Re: [PATCH v2 1/2] Input: exc3000 - Simplify probe() > > > > On Sat, Jul 22, 2023 at 05:51:17PM +0000, Biju Das wrote: > > > Hi Dmitry Torokhov, > > > > > > Thanks for the feedback. > > > > > > > Subject: Re: [PATCH v2 1/2] Input: exc3000 - Simplify probe() > > > > > > > > On Wed, Jul 19, 2023 at 06:43:47AM +0000, Biju Das wrote: > > > > > 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? > > > > > > > > > > > > > > > > > > > > > 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. > > > > > > > > Yes, something like this (which does not seem that involved to > > me...): > > > > > > Looks it will work. > > > > > > But there is some 2 additional checks in core code, every driver > > > which > > is not bus type need to go through this checks. > > > > > > Also in Bus specific callback, there are 2 additional checks. > > > > > > So, performance wise [1] is better. > > > > I do not believe this is a concern whatsoever: majority of > > architectures/boards have been converted to ACPI/DT, which are being > > matched first as they are now, so the fallback to bus-specific > > matching against bus-specific device ID tables will be very > infrequent. > > Additionally, device_get_match_data() is predominantly called from > > driver probe paths, so we need not be concerned with it being used > > with class devices or other kinds of devices not associated with a > bus. > > Looks like most of the i2c client driver uses similar handling for > ACPI/DT and ID tables. If that is the case, it is good to have this > proposed change which will simplify most of the drivers listed in [1] > > [1] > https://jpn01.safelinks.protection.outlook.com/?url=https%3A%2F%2Felixir > .bootlin.com%2Flinux%2Flatest%2FA%2Fident%2Fi2c_match_id&data=05%7C01%7C > biju.das.jz%40bp.renesas.com%7C2a07c353ab7649fdf29a08db8b42cca3%7C53d825 > 71da1947e49cb4625a166a4a2a%7C0%7C0%7C638256891245437404%7CUnknown%7CTWFp > bGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0% > 3D%7C3000%7C%7C%7C&sdata=tOxuTgGKc%2FQYFx94rYUJ8TDTWmGKkETzASV3qUjP2vk%3 > D&reserved=0 > > Eg: drivers/hwmon/pmbus/ibm-cffps.c > > enum versions vs = cffps_unknown; > const void *md = of_device_get_match_data(&client->dev); > const struct i2c_device_id *id; > > if (md) { > vs = (enum versions)md; > } else { > id = i2c_match_id(ibm_cffps_id, client); > if (id) > vs = (enum versions)id->driver_data; > } > > The above code can be converted to > vs = (enum versions)device_get_match_data(&client->dev); > > > > > > > > > Moreover, we need to avoid code duplication with [1] > > > > > > [1] > > > > If and when my proposed solution gets into the kernel we can drop > > i2c_get_match_data() altogether. > > Agreed. Will wait for other people's view on this topic. Also remove spi_get_device_match_data and Make i2c_match_id() and spi_get_device_id() as static and Replace all these with device_get_natch_data() from all i2c/spi client drivers. Can you please post a patch based on this? Cheers, Biju
