Re: [PATCH v4] iio : Add cm3218 smbus ara and acpi support

From: Mika Westerberg
Date: Mon Nov 27 2017 - 06:42:32 EST


On Sat, Nov 25, 2017 at 02:00:34PM +0000, Jonathan Cameron wrote:
> > There does not seem to be any way in ACPI to tell which "connection" is
> > used to describe ARA so that part currently is something each driver
> > needs to handle as they know the device the best. I don't think we have
> > any means to handle it in generic way in I2C core except to provide some
> > helpers that work on top of i2c_setup_smbus_alert() but understand ACPI
> > resources. Say provide function like this:
> >
> > int acpi_i2c_setup_smbus_alert(struct i2c_adapter *adapter, int index);
> >
> > Which then extracts automatically I2cSerialBus connection from "index"
> > and calls i2c_setup_smbus_alert() accordingly.
> >
> > In the long run we could introduce _DSD property that can be used to
> > name the connection in the same way DT does;
> >
> > Name (_CRS, ResourceTemplate () {
> > I2cSerialBus () { ... } // ARA
> > I2cSerialBus () { ... } // normal device address
> > })
> >
> > Name (_DSD, Package () {
> > ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
> > Package () {
> > Package () {"smbus_alert", 0} // Where 0 means the first I2cSerialBus
> > ...
> > }
> > })
> >
> > But it does not help the existing systems.
>
> I'm curious - how would we go about promoting this piece of common sense?

I guess a proper patch series including relevant mailing lists (like
linux-acpi and linux-i2c) would be a good starting point :)