Re: [PATCH 2/6] i2c: piix4: use i2c_adapter_dev()

[Jean Delvare <jdelvare@suse.de>]

Hi Bartosz,

On Tue, 23 Dec 2025 11:08:19 +0100, Bartosz Golaszewski wrote:
> Use i2c_adapter_dev() where applicable in order to avoid direct
> dereferencing of struct device embedded within struct i2c_adapter.

I will confess that I don't know what is wrong with the current way of
embedding struct device in a more specific device structure. I seem to
recall it was fairly standard to do things this way back when we
implemented this in the i2c subsystem. But I will trust you that this
change is needed now.

> 
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
> ---
>  drivers/i2c/busses/i2c-piix4.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
> index ac3bb550303fe5893822af50c385004c9292e695..4fe0c49284646a9f2910939c98b51ee6777e8b52 100644
> --- a/drivers/i2c/busses/i2c-piix4.c
> +++ b/drivers/i2c/busses/i2c-piix4.c
> @@ -788,7 +788,7 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
>  	u8 prev_port;
>  	int retval;
>  
> -	retval = piix4_sb800_region_request(&adap->dev, &adapdata->mmio_cfg);
> +	retval = piix4_sb800_region_request(i2c_adapter_dev(adap), &adapdata->mmio_cfg);
>  	if (retval)
>  		return retval;
>  
> @@ -859,7 +859,7 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
>  		piix4_imc_wakeup();
>  
>  release:
> -	piix4_sb800_region_release(&adap->dev, &adapdata->mmio_cfg);
> +	piix4_sb800_region_release(i2c_adapter_dev(adap), &adapdata->mmio_cfg);
>  	return retval;
>  }
>  
> @@ -947,7 +947,7 @@ static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba,
>  	adap->dev.parent = &dev->dev;
>  
>  	if (has_acpi_companion(&dev->dev)) {
> -		acpi_preset_companion(&adap->dev,
> +		acpi_preset_companion(i2c_adapter_dev(adap),
>  				      ACPI_COMPANION(&dev->dev),
>  				      hw_port_nr);
>  	}
> 

Acked-by: Jean Delvare <jdelvare@suse.de>

I see that you left one occurrence:

	adap->dev.parent = &dev->dev;

I presume we'll need a wrapper for this construct as well?

Thanks,
-- 
Jean Delvare
SUSE L3 Support