From: Heiner Kallweit <hkallweit1@gmail.com>
To: Wolfram Sang <wsa@kernel.org>, Andi Shyti <andi.shyti@kernel.org>,
Jean Delvare <jdelvare@suse.com>
Cc: "linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>
Subject: [PATCH v2] i2c: smbus: Prepare i2c_register_spd for usage on muxed segments
Date: Sat, 2 Mar 2024 21:39:13 +0100 [thread overview]
Message-ID: <d0b4aa2e-8b5d-4c27-8aab-164a089d95bd@gmail.com> (raw)
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>
---
v2:
- Make comments / messages more descriptive
- Remove second patch of the series to ask for testing on lkml
- change dev_err to dev_warn
---
drivers/i2c/i2c-smbus.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c
index 74807c6db..c45d09782 100644
--- a/drivers/i2c/i2c-smbus.c
+++ b/drivers/i2c/i2c-smbus.c
@@ -351,13 +351,20 @@ 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;
+ }
+ dev_info(&adap->dev, "%d/%d memory slots populated (from DMI)\n",
+ dimm_count, slot_count);
}
/*
--
2.44.0
next reply other threads:[~2024-03-02 20:39 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-02 20:39 Heiner Kallweit [this message]
2024-03-04 7:46 ` [PATCH v2] i2c: smbus: Prepare i2c_register_spd for usage on muxed segments Wolfram Sang
2024-03-04 20:20 ` Heiner Kallweit
2024-03-04 20:46 ` Wolfram Sang
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