Hi Andy,
On Tue, 10 Mar 2020 at 08:51, Andy Shevchenko < andriy.shevchenko@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_IRQIRQ_TYPE_EDGE_FALLING>;acpi,probed;hid-descr-addr = <0x20>;+};
Regards, Simon