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, and we assume that ACPI
developers will use the Linux ordering, as follows:
Device(SBUS) {
Name(_ADR, 0x00140000)
Name(_HID, "SMB0001")
Device(CH00) {
Name(_ADR, 0) // main SMBus adapter, Port 0
Name (_STR, Unicode ("Main SMBus adapter, Port 0"))
}
Device(CH01) {
Name(_ADR, 1) // main SMBus Port 2 (Port 1 label is undefined)
Name (_STR, Unicode ("Main SMBus adapter, Port 2"))
}
Device (CH02) {
Name(_ADR, 2) // ASF adapter (what Linux calls 'aux port')
Name (_STR, Unicode ("AUX / ASF SMBus adapter"))
}
}
[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>
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
---
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);
+ }
+
snprintf(adap->name, sizeof(adap->name),
"SMBus PIIX4 adapter%s at %04x", name, smba);
--
2.7.4
