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i2c: smbus: Prepare i2c_register_spd for usage on muxed segments 

If this is an adapter on a muxed bus segment, assume that each segment
is connected to a subset of the (> 8) overall memory slots. In this
case let's probe the maximum of 8 slots, however stop if the number
of overall populated slots is reached.

If we're not on a muxed segment and the total number of slots is > 8,
then warn because then not all SPD eeproms can be addressed.
Presumably the bus is muxed, but the mux config is missing.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
[wsa: removed a superfluous printout]
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
This commit is contained in:
Heiner Kallweit 2024-03-02 21:39:13 +01:00 committed by Wolfram Sang
parent eb52034436
commit 8821c83769
1 changed files with 12 additions and 7 deletions
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19
drivers/i2c/i2c-smbus.c
View File

@ -351,13 +351,18 @@ void i2c_register_spd(struct i2c_adapter *adap)
if (!dimm_count)
return;
dev_info(&adap->dev, "%d/%d memory slots populated (from DMI)\n",
dimm_count, slot_count);
if (slot_count > 8) {
dev_warn(&adap->dev,
"Systems with more than 8 memory slots not supported yet, not instantiating SPD\n");
return;
/*
* If we're a child adapter on a muxed segment, then limit slots to 8,
* as this is the max number of SPD EEPROMs that can be addressed per bus.
*/
if (i2c_parent_is_i2c_adapter(adap)) {
slot_count = 8;
} else {
if (slot_count > 8) {
dev_warn(&adap->dev,
"More than 8 memory slots on a single bus, contact i801 maintainer to add missing mux config\n");
return;
}
}
/*