linux-kernel - Re: [v5,3/5] USB: ohci: da8xx: Allow a regulator to handle VBUS

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Date:   Tue, 22 Nov 2016 15:18:26 +0100
From:   Axel Haslam <ahaslam@...libre.com>
To:     David Lechner <david@...hnology.com>
Cc:     Greg KH <gregkh@...uxfoundation.org>,
        Alan Stern <stern@...land.harvard.edu>,
        Kevin Hilman <khilman@...nel.org>, kishon@...com,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [v5,3/5] USB: ohci: da8xx: Allow a regulator to handle VBUS

On Mon, Nov 21, 2016 at 5:29 PM, David Lechner <david@...hnology.com> wrote:
> On 11/21/2016 04:22 AM, Axel Haslam wrote:
>>
>> Hi David,
>>
>> Thanks for the review,
>>
>
> You're welcome.
>
>>>>
>>>> @@ -160,15 +212,41 @@ static void ohci_da8xx_ocic_handler(struct
>>>> da8xx_ohci_root_hub *hub,
>>>>                 hub->set_power(port, 0);
>>>>  }
>>>>
>>>> +static int ohci_da8xx_regulator_event(struct notifier_block *nb,
>>>> +                               unsigned long event, void *data)
>>>> +{
>>>> +       struct da8xx_ohci_hcd *da8xx_ohci =
>>>> +                               container_of(nb, struct da8xx_ohci_hcd,
>>>> nb);
>>>> +       struct device *dev = da8xx_ohci->hcd->self.controller;
>>>> +
>>>> +       if (event & REGULATOR_EVENT_OVER_CURRENT) {
>>>> +               dev_warn(dev, "over current event\n");
>>>
>>>
>>>
>>> Won't this result in duplicate overcurrent warnings in the kernel log? It
>>> seems like in previous version of this patch series, we would get an
>>> overcurrent error from the core usb driver.
>>
>>
>> you mean in the regulator driver? i did not make changes to core usb.
>> but, no,  i did not add a print in the fixed regulator driver itself.
>> Since
>> the regulator is  a separate driver, and could be implemented with or
>> without
>> a trace, i think its better to leave this print. It shows that the usb
>> driver
>> has well received the notification.
>>
>
> No, I mean in drivers/usb/core/hub.c. There is
>
>         if (status & USB_PORT_STAT_OVERCURRENT)
>                 dev_err(&port_dev->dev, "over-current condition\n");
>
> and
>
>         if (status & HUB_STATUS_OVERCURRENT)
>                 dev_err(hub_dev, "over-current condition\n");
>
> In ohci_da8xx_hub_control(), we are setting RH_PS_POCI and RH_PS_OCIC, so
> these messages will be printed via the core hub driver. We don't need to
> print another message from the same event.
>
>

Hi David

I did a couple of tests, and i don't get those prints do you get them?.
What i understand is that they happen when we get a hub event that is
reporting the over current. Which is what the root hub of the davinci system
does not have, and why we use gpios instead).

Regards,
Axel.

>