6.6-stable review patch. If anyone has any objections, please let me know.
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From: Heiner Kallweit hkallweit1@gmail.com
[ Upstream commit caba40ec3531b0849f44502a03117796e8c9f4a1 ]
The DDR3 SPD data structure advertises the presence of a thermal sensor on a DDR3 module in byte 32, bit 7. Let's use this information to explicitly instantiate the thermal sensor I2C client instead of having to rely on class-based I2C probing.
The temp sensor i2c address can be derived from the SPD i2c address, so 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.
Note: Thermal sensors on DDR4 DIMM's are instantiated from the ee1004 driver.
Signed-off-by: Heiner Kallweit hkallweit1@gmail.com Link: https://lore.kernel.org/r/68113672-3724-44d5-9ff8-313dd6628f8c@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Stable-dep-of: f42c97027fb7 ("eeprom: at24: fix memory corruption race condition") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/misc/eeprom/at24.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+)
diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c index dbbf7db4ff2f4..e6d688817b106 100644 --- a/drivers/misc/eeprom/at24.c +++ b/drivers/misc/eeprom/at24.c @@ -581,6 +581,31 @@ static unsigned int at24_get_offset_adj(u8 flags, unsigned int byte_len) } }
+static void at24_probe_temp_sensor(struct i2c_client *client) +{ + struct at24_data *at24 = i2c_get_clientdata(client); + struct i2c_board_info info = { .type = "jc42" }; + int ret; + u8 val; + + /* + * Byte 2 has value 11 for DDR3, earlier versions don't + * support the thermal sensor present flag + */ + ret = at24_read(at24, 2, &val, 1); + if (ret || val != 11) + return; + + /* Byte 32, bit 7 is set if temp sensor is present */ + ret = at24_read(at24, 32, &val, 1); + if (ret || !(val & BIT(7))) + return; + + info.addr = 0x18 | (client->addr & 7); + + i2c_new_client_device(client->adapter, &info); +} + static int at24_probe(struct i2c_client *client) { struct regmap_config regmap_config = { }; @@ -780,6 +805,10 @@ static int at24_probe(struct i2c_client *client) } }
+ /* If this a SPD EEPROM, probe for DDR3 thermal sensor */ + if (cdata == &at24_data_spd) + at24_probe_temp_sensor(client); + pm_runtime_idle(dev);
if (writable)