On Mon, Oct 12, 2015 at 11:32:31AM -0700, Dustin Byford wrote: > I've been trying to consider the options, perhaps you can help my > understanding. Using the i801 driver as an example, the device is PCI > and the companion is associated with the PCI dev. The driver creates > another device for the I2C interface (parented by the PCI device) by > calling i2c_add_adapter(). The I2C dev has no ACPI companion. > > In the case of an I2C mux port, I've used acpi_preset_companion() to > associate each mux port I2C device with a ACPI node. Unlike the i801, > which has a single port, these companions are one per channel. It's not > an option to associate them all with the I2C mux device. > > It seems like the options are to: > > a) Special case the I2C mux to use the per-port I2C companions as I've > done here. > > b) Move (or copy?) the companion from the i801 PCI dev to the i801 I2C > dev. Then we would always look in the same place for the companion. > I think this approach has some advantages, at least it would make > more sense if an I2C PCI controller had more than one I2C port, but > I'm not sure that case exists. I didn't pursue this approach because > it was specifically avoided in change b34bb1ee. > > > What do you think? I'd be happy to try out any ideas you have. I would favour b) because that follows DT (the I2C host controller device and I2C adapter share the same DT node as far as I can tell). Neither of them have similar concept of I2C adapter as we have in Linux (which is the "virtual" device on top of the I2C host controller). -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
