On Mon, Feb 26, 2018 at 10:28:45AM +1000, Andrew Cooks wrote:
> Enable the i2c-piix4 SMBus controller driver to enumerate I2C slave
> devices using ACPI. It builds on the related I2C mux device work
> in commit 8eb5c87a92c0 ("i2c: add ACPI support for I2C mux ports")
>
> In the i2c-piix4 driver the adapters are enumerated as:
> Main SMBus adapter Port 0, Port 2, ..., aux port (i.e., ASF adapter)
>
> However, in the AMD BKDG documentation[1], the implied order of ports is:
> Main SMBus adapter Port 0, ASF adapter, Port 2, Port 3, ...
>
> This ordering difference is unfortunate. We assume that ACPI
> developers will use the Linux ordering.
>
> [1] 52740 BIOS and Kernel Developer's Guide (BKDG) for AMD Family 16h
> Models 30h-3Fh Processors
>
> Signed-off-by: Andrew Cooks <andrew.cooks@xxxxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-piix4.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
> index 01f1610..9a6cdc8 100644
> --- a/drivers/i2c/busses/i2c-piix4.c
> +++ b/drivers/i2c/busses/i2c-piix4.c
> @@ -837,6 +837,12 @@ static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba,
> /* set up the sysfs linkage to our parent device */
> adap->dev.parent = &dev->dev;
>
> + if (has_acpi_companion(&dev->dev)) {
> + acpi_preset_companion(&adap->dev,
> + ACPI_COMPANION(&dev->dev),
> + piix4_adapter_count);
nit:
acpi_preset_companion(&adap->dev,
ACPI_COMPANION(&dev->dev),
piix4_adapter_count);
> + }
> +
> snprintf(adap->name, sizeof(adap->name),
> "SMBus PIIX4 adapter%s at %04x", name, smba);
Hope this helps,
Tobin
