[PATCH i2c-tools] TODO: add file and describe items for the 4.5 release

[PATCH i2c-tools] TODO: add file and describe items for the 4.5 release

[Wolfram Sang]

We need help, especially with tests, for the next release. To make this
visible, document the planned items and explain where and how people can
participate.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 TODO | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 TODO

diff --git a/TODO b/TODO
new file mode 100644
index 0000000..290e610
--- /dev/null
+++ b/TODO
@@ -0,0 +1,23 @@
+Items for the 4.5 release
+=========================
+
+[.] make i2c-tools accept bus paths (Brigham Campbell)
+	[x] patches available: https://lore.kernel.org/r/20260530-accept-device-path-v3-0-20c01b8f6726@brighamcampbell.com
+	[ ] reviews and tests needed, please help
+
+[.] add DDR5 support to decode-dimms (Stephen Horvath)
+	[x] patches available: https://lore.kernel.org/r/20260629-ddr5-v3-0-07f45075a51a@outlook.com.au
+	[ ] reviews and tests needed, please help
+
+[.] add document to describe the release process (Jean Delvare)
+	[.] he agreed to the idea and wants to provide it
+
+[ ] print I2C_M flags in PRINT_HEADER (maybe Benoît Monin)
+	Benoît agreed but did not know when he has time. So, if someone else
+	wants to do it, happy hacking!
+
+[ ] utilize CROSS_COMPILE (maybe Wolfram Sang)
+	Guenter Roeck once did it, but his repo is gone. Merges still exist:
+	https://github.com/arche67/i2c-tools/commit/60581c572354dd5dbe98b78e3a0431cbc1167330
+
+	But can be written from scratch, too, of course. Any volunteers?
-- 
2.51.0

Re: [PATCH i2c-tools] TODO: add file and describe items for the 4.5 release

[Brigham Campbell]

On Sun Jul 5, 2026 at 12:10 PM MDT, Wolfram Sang wrote:
> We need help, especially with tests, for the next release. To make this
> visible, document the planned items and explain where and how people can
> participate.

> +[.] make i2c-tools accept bus paths (Brigham Campbell)
> +	[x] patches available: https://lore.kernel.org/r/20260530-accept-device-path-v3-0-20c01b8f6726@brighamcampbell.com
> +	[ ] reviews and tests needed, please help

Noticed a minor conflict after rebasing onto master, so I rolled a v4:
https://lore.kernel.org/r/20260705-accept-device-path-v4-0-c62caa708a9e@brighamcampbell.com

This latest revision includes no functional changes from v3.

> +[.] add DDR5 support to decode-dimms (Stephen Horvath)
> +	[x] patches available: https://lore.kernel.org/r/20260629-ddr5-v3-0-07f45075a51a@outlook.com.au
> +	[ ] reviews and tests needed, please help

Stephen, it looks like your series applies cleanly on top of my v4. I'm
not familiar with decode-dimms, but I do have a laptop with DDR5 memory.
If you can provide some instructions for testing, I'd be happy to
exercise this new code and report back.

In case it's relevant, here's the output of `i2cdetect -l` on my system:

```
i2c-0	i2c       	Synopsys DesignWare I2C adapter 	I2C adapter
i2c-1	i2c       	Synopsys DesignWare I2C adapter 	I2C adapter
i2c-2	i2c       	i915 gmbus dpa                  	I2C adapter
i2c-3	i2c       	i915 gmbus dpb                  	I2C adapter
i2c-4	i2c       	i915 gmbus dpc                  	I2C adapter
i2c-5	i2c       	i915 gmbus dpd                  	I2C adapter
i2c-6	i2c       	i915 gmbus dpe                  	I2C adapter
i2c-7	i2c       	i915 gmbus tc1                  	I2C adapter
i2c-8	i2c       	i915 gmbus tc2                  	I2C adapter
i2c-9	i2c       	i915 gmbus tc3                  	I2C adapter
i2c-10	i2c       	i915 gmbus tc4                  	I2C adapter
i2c-11	i2c       	AUX A/DDI A/PHY A               	I2C adapter
i2c-12	i2c       	AUX USBC1/DDI TC1/PHY TC1       	I2C adapter
i2c-13	i2c       	AUX USBC2/DDI TC2/PHY TC2       	I2C adapter
i2c-14	i2c       	AUX USBC3/DDI TC3/PHY TC3       	I2C adapter
i2c-15	smbus     	SMBus I801 adapter at 0000:00:1f.4	SMBus adapter
i2c-16	i2c       	usbio-i2c.0                     	I2C adapter
i2c-17	i2c       	usbio-i2c.1                     	I2C adapter
```

Thanks,
Brigham

Re: [PATCH i2c-tools] TODO: add file and describe items for the 4.5 release

[Stephen Horvath]

Hi Brigham,

On 6/7/26 14:45, Brigham Campbell wrote:
> Stephen, it looks like your series applies cleanly on top of my v4. I'm
> not familiar with decode-dimms, but I do have a laptop with DDR5 memory.
> If you can provide some instructions for testing, I'd be happy to
> exercise this new code and report back.

If you've got the spd5118 kernel module loaded (which usually happens
automatically), you just have to run `sudo ./decode-dimms`. You can
manually bind spd5118 if it isn't autodetecting, your dimms should be on
your i801 bus (or PIIX4 for AMD), usually with an address between 0x50
to 0x57.

If you're willing to dump the eeprom too, the location is usually at
`/sys/bus/i2c/drivers/spd5118/<fill with bus-addr>/eeprom` and run it
through `hexdump -C` just to make it plain text.

Thanks!
Steve.

Re: [PATCH i2c-tools] TODO: add file and describe items for the 4.5 release

[Brigham Campbell]

On Sun Jul 5, 2026 at 11:19 PM MDT, Stephen Horvath wrote:
> If you've got the spd5118 kernel module loaded (which usually happens
> automatically), you just have to run `sudo ./decode-dimms`. You can
> manually bind spd5118 if it isn't autodetecting, your dimms should be on
> your i801 bus (or PIIX4 for AMD), usually with an address between 0x50
> to 0x57.

No, the spd5118 module doesn't appear to be loaded automatically:

```
$ lsmod | grep spd5118
$ zgrep SENSORS_SPD5118 /proc/config.gz
CONFIG_SENSORS_SPD5118=m
CONFIG_SENSORS_SPD5118_DETECT=y
```

Using `i2cdetect` on the i801 SMBus controller, I see that it reports no
attached i2c devices:

```
$ sudo ./tools/i2cdetect -y /dev/i2c-15
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:                         -- -- -- -- -- -- -- -- 
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
70: -- -- -- -- -- -- -- --                         
$ 
```

Interestingly, I see warnings in dmesg upon running the above i2cdetect
command. Taking a quick look at the kernel code, this appears to be
caused by some transient controller hardware busy state which is
overcome by the kernel's bus arbitration retry logic (See
`drivers/i2c/busses/i2c-i801.c:1552`). It's strange that a bus with no
devices attached would ever become busy...

```
...
[  +0.000009] i801_smbus 0000:00:1f.4: SMBus is busy, can't use it!
[  +0.000010] i801_smbus 0000:00:1f.4: SMBus is busy, can't use it!
[  +0.000010] i801_smbus 0000:00:1f.4: SMBus is busy, can't use it!
[  +0.000009] i801_smbus 0000:00:1f.4: SMBus is busy, can't use it!
[  +0.000010] i801_smbus 0000:00:1f.4: SMBus is busy, can't use it!
...
```

In any case, if I am unable to exercise your code, I would still be glad
to review it.

Cheers,
Brigham

Re: [PATCH i2c-tools] TODO: add file and describe items for the 4.5 release

[Benoît Monin]

Hi Wolfram,

On Sunday, 5 July 2026 at 20:10:42 CEST, Wolfram Sang wrote:
> We need help, especially with tests, for the next release. To make this
> visible, document the planned items and explain where and how people can
> participate.
> 
[...]
> +[ ] print I2C_M flags in PRINT_HEADER (maybe Benoît Monin)
> +	Benoît agreed but did not know when he has time. So, if someone else
> +	wants to do it, happy hacking!
> +
I'll try to send a patch for that today.

Best regards,
-- 
Benoît Monin, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com