On 15.11.2023 12:17, Heiner Kallweit wrote: > Jean and me are discussing how to best instantiate temperature sensors > that can be found on RAM modules. First idea was to extend > i2c_register_spd() but I think reading the "temp sensor present" flag > from SPD can't be properly done from an i2c core level. > Therefore, for DDR4, do it from the ee1004 driver. > > The temp sensor i2c address can be derived from the SPD i2c address, > so I think we can directly instantiate the device and don't have to > probe for it. > If the temp sensor has been instantiated already by other means > (e.g. class-based auto-detection), then the busy-check in > i2c_new_client_device will detect this. > > Link: https://www.spinics.net/lists/linux-i2c/msg65963.html > Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx> > --- > drivers/misc/eeprom/ee1004.c | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > diff --git a/drivers/misc/eeprom/ee1004.c b/drivers/misc/eeprom/ee1004.c > index a1acd7713..4bce8f9d9 100644 > --- a/drivers/misc/eeprom/ee1004.c > +++ b/drivers/misc/eeprom/ee1004.c > @@ -158,6 +158,22 @@ static struct bin_attribute *ee1004_attrs[] = { > > BIN_ATTRIBUTE_GROUPS(ee1004); > > +static void ee1004_probe_temp_sensor(struct i2c_client *client) > +{ > + struct i2c_board_info info = { .type = "jc42" }; > + u8 byte14; > + int ret; > + > + /* byte 14, bit 7 is set if temp sensor is present */ > + ret = ee1004_eeprom_read(client, &byte14, 14, 1); > + if (ret != 1 || !(byte14 & BIT(7))) > + return; > + > + info.addr = 0x18 | (client->addr & 7); > + > + i2c_new_client_device(client->adapter, &info); > +} > + > static void ee1004_cleanup(int idx) > { > if (--ee1004_dev_count == 0) > @@ -204,6 +220,9 @@ static int ee1004_probe(struct i2c_client *client) > err = -EOPNOTSUPP; > goto err_clients; > } > + > + ee1004_probe_temp_sensor(client); > + > mutex_unlock(&ee1004_bus_lock); > > dev_info(&client->dev, Jean, do you have any feedback on this one? Also not sure why this patch is marked "superseded" in patchwork.
