[PATCH RFC 0/4] Start unification of of_device_id and i2c_device_id

Dmitry Torokhov
2023-08-14T21:54:14Z

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@gmail.com>
---
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