Subject: [linux-sunxi] Re: [PATCH 5/5] ARM: sun5i: Add C.H.I.P DTS

From: [email-masked] (Hans de Goede)
Date: Tue, 22 Sep 2015 15:01:58 +0200

Hi,

On 22-09-15 14:57, Chen-Yu Tsai wrote:
> On Tue, Sep 22, 2015 at 8:47 PM, Maxime Ripard
> <[email-masked]> wrote:

<snip>

>>>> +&usb_otg {
>>>> +       dr_mode = "otg";
>>>> +       status = "okay";
>>>> +};
>>>> +
>>>> +&usbphy {
>>>> +       pinctrl-names = "default";
>>>> +       pinctrl-0 = <&chip_id_det_pin>;
>>>> +       status = "okay";
>>>> +
>>>> +       usb0_id_det-gpio = <&pio 6 2 GPIO_ACTIVE_HIGH>; /* PG2 */
>>>
>>> Better leave a comment here saying VBUS detection requires AXP209
>>> usb-power-supply support.
>>
>> Does it? It can be powered by a battery, with or without VBUS, and
>> that wouldn't be tied to the fact that the power-supply is USB or
>> something else.
>
> The AXP209 VBUS / USB power-supply also doubles for VBUS detection,
> which on most boards is done using a separate GPIO pin. Hans posted
> support for the AXP20X power-supply driver, and support in the usb
> phy driver using it for VBUS detection.

Ack.

> In short, this is not about "power supply" but VBUS detection. IIRC,
> if no VBUS detection method is provided, the phy driver just waits a
> period of time after an ID pin change and then considers VBUS invalid.

Right, but that is a hack for boards with no / broken vbus detection
(or vbus control), we really want to use vbus-det where available,
so I agree that a TODO comment here would be good.

Regards,

Hans