Re: [PATCH 0/3] Add a host power device

[Philippe Mathieu-Daudé]

Hi Jian,

On 19/9/22 19:21, Jian Zhang wrote:
> This patchset adds a host power device and added it into the g220a
> mahcine. The BMC have a important is to control the power of the host,
> usually it is nessary in a hardware platform.
>
> The BMC(soc) usually had a output pin to control the power of the host,
> and a input pin to get the power status of the host.
>
> The host power device is a generic device to simulate the host power,
> accept the power control command from the BMC and report the power
> status.
>
> Test on the g220a machine, the host power control command can be simply
> work.
>
> Jian Zhang (3):
>    hw/gpio/aspeed_gpio: Add gpios in/out init
>    hw/misc/host_power: Add a simple host power device
>    hw/arm/aspeed: g220a: Add host-power device

"power-good" is just a TYPE_LED object, but it doesn't seem you are
really interested in using it.

My understanding of your "power-button" is a latching switch.

This could be indeed useful. I'd name this model TYPE_LATCHING_SWITCH
and put it in hw/misc/latching-switch.c (since it is external to a
SoC). It has one input and one output. Naming them is not particularly
useful IMHO. The triggering edge should be a property (it might have
a default, positive/negative), and the switch state must to be in
vmstate for the object to be migratable.

("power-good"/"power-button" is what this particular board choose to
use the latch switch input/output for).

Do you mind renaming your series accordingly ("latching switch"),
and adding the vmstate?

Also I'd reorder your series as 2,1,3:
- introduce the new device
- prepare aspeed_gpio
- wire aspeed_g220a

Regards,

Phil.