i2c: smbus: Support up to 8 SPD EEPROMs

JIRA: https://issues.redhat.com/browse/RHEL-47257

commit 13e3a51
Author: Jean Delvare <jdelvare@suse.de>
Date:   Tue Nov 14 15:13:28 2023 +0100

    i2c: smbus: Support up to 8 SPD EEPROMs

    I originally restricted i2c_register_spd() to only support systems
    with up to 4 memory slots, so that we can experiment with it on
    a limited numbers of systems. It's been more than 3 years and it
    seems to work just fine, so the time has come to lift this arbitrary
    limitation.

    The maximum number of memory slots which can be connected to a single
    I2C segment is 8, so support that many SPD EEPROMs. Any system with
    more than 8 memory slots would have either multiple SMBus channels
    or SMBus multiplexing, so it would need dedicated care. We'll get to
    that later as needed.

    Signed-off-by: Jean Delvare <jdelvare@suse.de>
    Signed-off-by: Wolfram Sang <wsa@kernel.org>

Signed-off-by: David Arcari <darcari@redhat.com>

Author: darcari

drivers/i2c/i2c-smbus.c

@@ -310,8 +310,8 @@ EXPORT_SYMBOL_GPL(i2c_free_slave_host_notify_device);
  * target systems are the same.
  * Restrictions to automatic SPD instantiation:
  *  - Only works if all filled slots have the same memory type
- *  - Only works for DDR2, DDR3 and DDR4 for now
- *  - Only works on systems with 1 to 4 memory slots
+ *  - Only works for DDR, DDR2, DDR3 and DDR4 for now
+ *  - Only works on systems with 1 to 8 memory slots
  */
 #if IS_ENABLED(CONFIG_DMI)
 void i2c_register_spd(struct i2c_adapter *adap)
@@ -356,9 +356,9 @@ void i2c_register_spd(struct i2c_adapter *adap)
 	dev_info(&adap->dev, "%d/%d memory slots populated (from DMI)\n",
 		 dimm_count, slot_count);
 
-	if (slot_count > 4) {
+	if (slot_count > 8) {
 		dev_warn(&adap->dev,
-			 "Systems with more than 4 memory slots not supported yet, not instantiating SPD\n");
+			 "Systems with more than 8 memory slots not supported yet, not instantiating SPD\n");
 		return;
 	}