On 6 December 2012 06:57, Ming Lei <tom.leim...@gmail.com> wrote:
> On Thu, Dec 6, 2012 at 12:49 AM, Roger Quadros <rog...@ti.com> wrote:
>> On 12/03/2012 05:00 AM, Ming Lei wrote:
>>> On Mon, Dec 3, 2012 at 12:02 AM, Andy Green <andy.gr...@linaro.org> wrote:
>>>> On 02/12/12 23:01, the mail apparently from Ming Lei included:
>>>>
>>>>> Power controller is an abstract on simple power on/off switch.
>>>>>
>>>>> One power controller can bind to more than one device, which
>>>>> provides power logically, for example, we can think one usb port
>>>>> in hub provides power to the usb device attached to the port, even
>>>>> though the power is supplied actually by other ways, eg. the usb
>>>>> hub is a self-power device. From hardware view, more than one
>>>>> device can share one power domain, and power controller can power
>>>>> on if one of these devices need to provide power, and power off if
>>>>> all these devices don't need to provide power.
>>>>
>>>>
>>>> What stops us using struct regulator here? If you have child regulators
>>>> supplied by a parent supply, isn't that the right semantic already without
>>>> introducing a whole new thing? Apologies if I missed the point.
>>>
>>> There are two purposes:
>>>
>>> One is to hide the implementation details of the power controller because
>>> the user doesn't care how it is implemented, maybe clock, regulator, gpio
>>> and other platform dependent stuffs involved, so the patch simplify the
>>> usage
>>> from the view of users.
>>>
>>
>> Which user are you talking about?
>
> Here it is the usb port device.
>
> At least, there are many boards which have hardwired and self-powered usb
> devices, so in theory they can benefits from the power controller. Maybe
> only regulator and clock can't be covered completely for other boards.
>
> The patch can make usb port deal with the 'power controller' only, and make it
> avoid to deal with regulators/clocks/... directly.
>
I am curious too, except for clocks and voltage supplies (regulators),
what other external resources does a chip need ?
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