Re: [PATCH] PCI/pwrctrl: tc9563: take i2c adapter module reference

[Bjorn Helgaas <helgaas@kernel.org>]

On Thu, Jul 16, 2026 at 03:25:32PM +0200, Johan Hovold wrote:
> The i2c subsystem currently blocks during adapter deregistration
> whenever there are consumers holding a reference.
> 
> Switch to using of_get_i2c_adapter_by_node() which also takes a
> reference to the adapter module so that an attempt to unload the module
> while in use fails gracefully instead of blocking uninterruptibly.
> 
> Signed-off-by: Johan Hovold <johan@kernel.org>

Applied to pci/pwrctrl for v7.3, thanks!

Gemini suggested minor commit log rewording, let me know if it makes it
worse.  I do like the impact being mentioned in the subject:

  PCI/pwrctrl: tc9563: Avoid uninterruptible hang on in-use I2C module unload

  The I2C subsystem blocks during adapter deregistration if there are
  consumers actively holding a reference.

  Switch to of_get_i2c_adapter_by_node(), which also takes a reference to the
  adapter module, so an attempt to unload the module while in use will fail
  gracefully instead of blocking uninterruptibly.

> ---
>  drivers/pci/pwrctrl/pci-pwrctrl-tc9563.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/pci/pwrctrl/pci-pwrctrl-tc9563.c b/drivers/pci/pwrctrl/pci-pwrctrl-tc9563.c
> index 1555e8a9b3ca..e6a8abd9da8e 100644
> --- a/drivers/pci/pwrctrl/pci-pwrctrl-tc9563.c
> +++ b/drivers/pci/pwrctrl/pci-pwrctrl-tc9563.c
> @@ -548,7 +548,7 @@ static int tc9563_pwrctrl_probe(struct platform_device *pdev)
>  		return dev_err_probe(dev, ret, "Failed to read i2c-parent property\n");
>  
>  	i2c_node = of_parse_phandle(dev->of_node, "i2c-parent", 0);
> -	tc9563->adapter = of_find_i2c_adapter_by_node(i2c_node);
> +	tc9563->adapter = of_get_i2c_adapter_by_node(i2c_node);
>  	of_node_put(i2c_node);
>  	if (!tc9563->adapter)
>  		return dev_err_probe(dev, -EPROBE_DEFER, "Failed to find I2C adapter\n");
> @@ -556,7 +556,7 @@ static int tc9563_pwrctrl_probe(struct platform_device *pdev)
>  	tc9563->client = i2c_new_dummy_device(tc9563->adapter, addr);
>  	if (IS_ERR(tc9563->client)) {
>  		dev_err(dev, "Failed to create I2C client\n");
> -		put_device(&tc9563->adapter->dev);
> +		i2c_put_adapter(tc9563->adapter);
>  		return PTR_ERR(tc9563->client);
>  	}
>  
> @@ -624,7 +624,7 @@ static int tc9563_pwrctrl_probe(struct platform_device *pdev)
>  	tc9563_pwrctrl_power_off(&tc9563->pwrctrl);
>  remove_i2c:
>  	i2c_unregister_device(tc9563->client);
> -	put_device(&tc9563->adapter->dev);
> +	i2c_put_adapter(tc9563->adapter);
>  	return ret;
>  }
>  
> @@ -636,7 +636,7 @@ static void tc9563_pwrctrl_remove(struct platform_device *pdev)
>  
>  	tc9563_pwrctrl_power_off(&tc9563->pwrctrl);
>  	i2c_unregister_device(tc9563->client);
> -	put_device(&tc9563->adapter->dev);
> +	i2c_put_adapter(tc9563->adapter);
>  }
>  
>  static const struct of_device_id tc9563_pwrctrl_of_match[] = {
> -- 
> 2.54.0
>