This enables 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, and 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 cc38dc3..65e6390 100644 --- a/drivers/i2c/busses/i2c-piix4.c +++ b/drivers/i2c/busses/i2c-piix4.c @@ -845,6 +845,12 @@ 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++); + } + snprintf(adap->name, sizeof(adap->name), "SMBus PIIX4 adapter%s at %04x", name, smba); -- 2.7.4