Re: [PATCH v2 01/12] i2c: allow setting the parent device and OF node through the adapter struct

[Bartosz Golaszewski]

On Mon, 2 Mar 2026 11:38:27 +0100, Kalle Niemi <kaleposti@xxxxxxxxx> said:
> On 3/2/26 10:55, Bartosz Golaszewski wrote:
>> On Mon, Mar 2, 2026 at 8:47 AM Kalle Niemi <kaleposti@xxxxxxxxx> wrote:
>>> On 2/23/26 11:05, Bartosz Golaszewski wrote:
>>>> In order to stop i2c bus drivers from dereferencing the struct device
>>>> embedded in struct i2c_adapter, let's allow configuring the parent
>>>> device and OF-node of the adapter directly through dedicated fields.
>>>> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>
>>>> ---
>>> Hello,
>>> Automated driver test system bisected this commit to be the first bad
>>> commit, linux-next next-20260227 was tested. Failed tests include driver
>>> tests for ROHM PMIC and accelerometers, which are connected to
>>> BeagleBone Black.
>>> The failed driver tests all fail to first i2cget and the tests stop
>>> there: "Could not open file '/dev/i2c-2' or 'dev/i2c/2': No such file or
>>> directory".
>> Wolfram: well, now it would actually be useful to know which commit
>> exactly is the culprit so maybe splitting the changes is not a bad
>> idea after all.
>> Kalle: which i2c bus driver fails here? Any errors in kernel log?
>> Bart
>
> Hello Bart,
>
> i2c-1 and i2c-2 are failing. I am not seeing any i2c errors in kernel log. I got two failures without the dmesg available (this is bugged test sequence, and not a kernel crash), but those got the same stdout message "Could not open file ...." as all others.
>
> -Kalle
>

I meant what driver are you using but I suppose it's i2c-omap.

Can you try the following change and let me know if it fixes the issue?

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index dd8cec9b04c6..01656f82d2c6 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -1548,6 +1548,11 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
 	if (adap->timeout == 0)
 		adap->timeout = HZ;

+	if (!adap->dev.parent)
+		adap->dev.parent = adap->parent;
+	if (!adap->dev.of_node)
+		adap->dev.of_node = adap->of_node;
+
 	/* register soft irqs for Host Notify */
 	res = i2c_setup_host_notify_irq_domain(adap);
 	if (res) {
@@ -1561,11 +1566,6 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
 	adap->dev.type = &i2c_adapter_type;
 	device_initialize(&adap->dev);

-	if (!adap->dev.parent)
-		adap->dev.parent = adap->parent;
-	if (!adap->dev.of_node)
-		adap->dev.of_node = adap->of_node;
-
 	/*
 	 * This adapter can be used as a parent immediately after device_add(),
 	 * setup runtime-pm (especially ignore-children) before hand.

Bart