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

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Date:   Mon, 21 Nov 2016 10:29:14 -0600
From:   David Lechner <david@...hnology.com>
To:     Axel Haslam <ahaslam@...libre.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 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.