Re: [PATCH v4 01/29] Revert "treewide: Fix probing of devices in DT overlays"

Kalle Niemi
2025-11-28T10:15:08Z

On 11/27/25 03:54, Rob Herring wrote:
> On Tue, Nov 25, 2025 at 12:43 AM Matti Vaittinen
> <mazziesaccount@gmail.com> wrote:
>> On 24/11/2025 19:01, Rob Herring wrote:
>>> On Mon, Nov 24, 2025 at 10:44 AM Kalle Niemi <kaleposti@gmail.com> wrote:
>>>>
>>>> On 11/24/25 16:53, Rob Herring wrote:
>>>>> On Mon, Nov 24, 2025 at 8:48 AM Kalle Niemi <kaleposti@gmail.com> wrote:
>>>>>> On 10/15/25 10:13, Herve Codina wrote:
>>>>>>> From: Saravana Kannan <saravanak@google.com>
>>>>>>>
>>>>>>> This reverts commit 1a50d9403fb90cbe4dea0ec9fd0351d2ecbd8924.
>>>>>>>
>>>>>>> While the commit fixed fw_devlink overlay handling for one case, it
>>>>>>> broke it for another case. So revert it and redo the fix in a separate
>>>>>>> patch.
>>>>>>>
>>>>>>> Fixes: 1a50d9403fb9 ("treewide: Fix probing of devices in DT overlays")
>>>>>>> Reported-by: Herve Codina <herve.codina@bootlin.com>
>>>>>>> Closes: https://lore.kernel.org/lkml/CAMuHMdXEnSD4rRJ-o90x4OprUacN_rJgyo8x6=9F9rZ+-KzjOg@mail.gmail.com/
>>>>>>> Closes: https://lore.kernel.org/all/20240221095137.616d2aaa@bootlin.com/
>>>>>>> Closes: https://lore.kernel.org/lkml/20240312151835.29ef62a0@bootlin.com/
>>>>>>> Signed-off-by: Saravana Kannan <saravanak@google.com>
>>>>>>> Link: https://lore.kernel.org/lkml/20240411235623.1260061-2-saravanak@google.com/
>>>>>>> Signed-off-by: Herve Codina <herve.codina@bootlin.com>
>>>>>>> Acked-by: Mark Brown <broonie@kernel.org>
>>>>>>> ---
>>>>>>> drivers/bus/imx-weim.c | 6 ------
>>>>>>> drivers/i2c/i2c-core-of.c | 5 -----
>>>>>>> drivers/of/dynamic.c | 1 -
>>>>>>> drivers/of/platform.c | 5 -----
>>>>>>> drivers/spi/spi.c | 5 -----
>>>>>>> 5 files changed, 22 deletions(-)
>>>>>>>
>>>>>>> diff --git a/drivers/bus/imx-weim.c b/drivers/bus/imx-weim.c
>>>>>>> index 83d623d97f5f..87070155b057 100644
>>>>>>> --- a/drivers/bus/imx-weim.c
>>>>>>> +++ b/drivers/bus/imx-weim.c
>>>>>>> @@ -327,12 +327,6 @@ static int of_weim_notify(struct notifier_block *nb, unsigned long action,
>>>>>>> "Failed to setup timing for '%pOF'\n", rd->dn);
>>>>>>>
>>>>>>> if (!of_node_check_flag(rd->dn, OF_POPULATED)) {
>>>>>>> - /*
>>>>>>> - * Clear the flag before adding the device so that
>>>>>>> - * fw_devlink doesn't skip adding consumers to this
>>>>>>> - * device.
>>>>>>> - */
>>>>>>> - rd->dn->fwnode.flags &= ~FWNODE_FLAG_NOT_DEVICE;
>>>>>>> if (!of_platform_device_create(rd->dn, NULL, &pdev->dev)) {
>>>>>>> dev_err(&pdev->dev,
>>>>>>> "Failed to create child device '%pOF'\n",
>>>>>>> diff --git a/drivers/i2c/i2c-core-of.c b/drivers/i2c/i2c-core-of.c
>>>>>>> index eb7fb202355f..30b48a428c0b 100644
>>>>>>> --- a/drivers/i2c/i2c-core-of.c
>>>>>>> +++ b/drivers/i2c/i2c-core-of.c
>>>>>>> @@ -176,11 +176,6 @@ static int of_i2c_notify(struct notifier_block *nb, unsigned long action,
>>>>>>> return NOTIFY_OK;
>>>>>>> }
>>>>>>>
>>>>>>> - /*
>>>>>>> - * Clear the flag before adding the device so that fw_devlink
>>>>>>> - * doesn't skip adding consumers to this device.
>>>>>>> - */
>>>>>>> - rd->dn->fwnode.flags &= ~FWNODE_FLAG_NOT_DEVICE;
>>>>>>> client = of_i2c_register_device(adap, rd->dn);
>>>>>>> if (IS_ERR(client)) {
>>>>>>> dev_err(&adap->dev, "failed to create client for '%pOF'\n",
>>>>>>> diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
>>>>>>> index 2eaaddcb0ec4..b5be7484fb36 100644
>>>>>>> --- a/drivers/of/dynamic.c
>>>>>>> +++ b/drivers/of/dynamic.c
>>>>>>> @@ -225,7 +225,6 @@ static void __of_attach_node(struct device_node *np)
>>>>>>> np->sibling = np->parent->child;
>>>>>>> np->parent->child = np;
>>>>>>> of_node_clear_flag(np, OF_DETACHED);
>>>>>>> - np->fwnode.flags |= FWNODE_FLAG_NOT_DEVICE;
>>>>>>>
>>>>>>> raw_spin_unlock_irqrestore(&devtree_lock, flags);
>>>>>>>
>>>>>>> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
>>>>>>> index f77cb19973a5..ef9445ba168b 100644
>>>>>>> --- a/drivers/of/platform.c
>>>>>>> +++ b/drivers/of/platform.c
>>>>>>> @@ -739,11 +739,6 @@ static int of_platform_notify(struct notifier_block *nb,
>>>>>>> if (of_node_check_flag(rd->dn, OF_POPULATED))
>>>>>>> return NOTIFY_OK;
>>>>>>>
>>>>>>> - /*
>>>>>>> - * Clear the flag before adding the device so that fw_devlink
>>>>>>> - * doesn't skip adding consumers to this device.
>>>>>>> - */
>>>>>>> - rd->dn->fwnode.flags &= ~FWNODE_FLAG_NOT_DEVICE;
>>>>>>> /* pdev_parent may be NULL when no bus platform device */
>>>>>>> pdev_parent = of_find_device_by_node(parent);
>>>>>>> pdev = of_platform_device_create(rd->dn, NULL,
>>>>>>> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
>>>>>>> index 2e0647a06890..b22944a207c9 100644
>>>>>>> --- a/drivers/spi/spi.c
>>>>>>> +++ b/drivers/spi/spi.c
>>>>>>> @@ -4791,11 +4791,6 @@ static int of_spi_notify(struct notifier_block *nb, unsigned long action,
>>>>>>> return NOTIFY_OK;
>>>>>>> }
>>>>>>>
>>>>>>> - /*
>>>>>>> - * Clear the flag before adding the device so that fw_devlink
>>>>>>> - * doesn't skip adding consumers to this device.
>>>>>>> - */
>>>>>>> - rd->dn->fwnode.flags &= ~FWNODE_FLAG_NOT_DEVICE;
>>>>>>> spi = of_register_spi_device(ctlr, rd->dn);
>>>>>>> put_device(&ctlr->dev);
>>>>>>>
>>>>>> Sorry, some of you will receive this message now for second time. First
>>>>>> message was sent to older series of patches.
>>>>>> -
>>>>>>
>>>>>> Hello,
>>>>>>
>>>>>> Test system testing drivers for ROHM ICs bisected this commit to cause
>>>>>> BD71847 drivers probe to not be called.
>>>>> This driver (and overlay support) is in linux-next or something out of
>>>>> tree on top of linux-next?
>>>>>
>>>>> Rob
>>>> Yes the driver is in mainline linux: /drivers/mfd/rohm-bd718x7.c
>>> I don't see any support to apply overlays in that driver.
>> Ah. Sorry for the confusion peeps. I asked Kalle to report this without
>> proper consideration. 100% my bad.
>>
>> While the bd718x7 drive indeed is mainline (and tested), the actual
>> 'glue-code' doing the overlay is part of the downstream test
>> infrastructure. So yes, this is not a bug in upstream kernel - this
>> falls in the category of an upstream change causing downstream things to
>> break. So, feel free to say: "Go fix your code" :)
>>
>> Now that this is sorted, if someone is still interested in helping us to
>> get our upstream drivers tested - the downstream piece is just taking
>> the compiled device-tree overlay at runtime (via bin-attribute file),
>> and applying it using the of_overlay_fdt_apply(). The approach is
>> working for our testing purposes when the device is added to I2C/SPI
>> node which is already enabled. However, in case where we have the I2C
>> disabled, and enable it in the same overlay where we add the new device
>> - then the new device does not get probed.
>>
>> I would be really grateful if someone had a pointer for us.
> Seems to be fw_devlink related. I suppose if you turn it off it works?
> There's info about the dependencies in sysfs or maybe debugfs. I don't
> remember the details, but that should help to tell you why things
> aren't probing.
>
> I've dropped the changes for 6.18 for now. No one really seems to be
> in need of them yet AFAICT.
>
> Rob
Hello,

Thank you for the help. We are going to look into sysfs / debugfs as
soon as we have time.

I tried with this and result was the same, BD71847 was not probed:
[    0.000000] Kernel command line: console=ttyO0,115200n8 root=/dev/nfs
rw nfsroot=192.168.255.126:/home/user01/nfs,nfsvers=3
ip=192.168.255.1:192.168.255.126::255.255.255.0:bbb1:eth0 nfsrootdebug
fw_devlink=no

With todays linux-next the BD71847 got probed; I assume the changes got
dropped for the moment.

Kalle