Hi Andy, On Tue, 10 Mar 2020 at 08:51, Andy Shevchenko < andriy.shevche...@linux.intel.com> wrote: > > On Sun, Mar 08, 2020 at 09:44:37PM -0600, Simon Glass wrote: > > Devices need to report various identifiers in the ACPI tables. Rather than > > hard-coding these in drivers it is typically better to put them in the > > device tree. > > > > Add a binding file to describe this. > > ... > > > +Device bindings are described by their own individual binding files. > > + > > +U-Boot provides for some optional properties which are documented here. See > > +also hid-over-i2c.txt which describes HID devices. > > + > > + - acpi,has-power-resource : (boolean) true if this device has a power resource. > > + This causes a PRIC (ACPI PowerResource) to be written containing the > > What is PRIC? > > > + properties provided by this binding, to describe how to handle powering the > > + device up and down using GPIOs > > > + - acpi,compatible : compatible string to report > > Hmm... I didn't get this. Is it ACPI _CID?
Will add a pointer to the Linux ACPI docs for this. > > > + - acpi,desc : Contains the string to use as the _DDN (DOS (Disk Operating > > + System) Device Name) > > > + - acpi,hid : Contains the string to use as the HID (Hardware ID) > > + identifier _HID > > HID can be dropped to avoid confusion with below. OK I am actually dropping the next line. > > > + - hid-descr-addr : HID register offset (for Human Interface Devices) > > > + - acpi,probed : Tells U-Boot to add 'linux,probed' to the ACPI tables so that > > + Linux will not re-init the device > > Why? How do we know that Linux will work correctly? Again, we must not depend > on the OS behaviour. The wording is incorrect, will update. This is effectively an 'optional' device. > > > + - acpi,uid : _UID value for device > > + > > + > > +Example > > +------- > > + > > +synaptics_touchpad: synaptics-touchpad@2c { > > + compatible = "hid-over-i2c"; > > + reg = <0x2c>; > > + acpi,hid = "PNP0C50"; > > + acpi,desc = "Synaptics Touchpad"; > > + interrupts-extended = <&acpi_gpe GPIO_18_IRQ > > + IRQ_TYPE_EDGE_FALLING>; > > + acpi,probed; > > + hid-descr-addr = <0x20>; > > +}; Regards, Simon