i2c_device_id is using unsigned long as driver data, whereas of_device_id is using a void pointer. Normally drivers use them both as either a pointer or a scalar, but in some cases driver's authors chose to treat one as a pointer and another as a scalar that is being used as an index in array of chip-specific data, i.e. something like this: data = device_get_match_data(...); if (!data) { id = i2c_client_get_device_id(...); data = &some_array[id->driver_data]; } This makes it hard to turn device_get_match_data() into truly generic function working well for ACPI and DT, as well as for legacy cases. So let's try to switch i2c_device_id to also use a void pointer and first switch drivers with the patterns above to it, and then the rest of them. I did a conversion of a couple of drivers in i2c to illustrate. Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> --- Dmitry Torokhov (4): i2c: start migrating to a pointer in i2c_device_id i2c: mux: ltc4306: convert to using a pointer in i2c_device_id i2c: mux: pca954x: convert to using a pointer in i2c_device_id i2c: slave-eeprom: convert to using a pointer in i2c_device_id drivers/i2c/i2c-core-base.c | 2 +- drivers/i2c/i2c-slave-eeprom.c | 99 ++++++++++++++++++++++++------------- drivers/i2c/muxes/i2c-mux-ltc4306.c | 7 ++- drivers/i2c/muxes/i2c-mux-pca954x.c | 28 +++++------ include/linux/mod_devicetable.h | 3 +- 5 files changed, 86 insertions(+), 53 deletions(-) --- base-commit: 21ef7b1e17d039053edaeaf41142423810572741 change-id: 20230814-i2c-id-rework-9a4742e9ee52 Best regards, -- Dmitry