linux-kernel - Re: [PATCH/RFT v2 12/17] USB: ochi-da8xx: Use a regulator for vbus/overcurrent

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Message-ID: <CAKXjFTOxQ58rThpPw9t73k-BBZ8YKGvMhWfAG1r+3kC=GJVxWg@mail.gmail.com>
Date:   Tue, 25 Oct 2016 10:24:50 +0200
From:   Axel Haslam <ahaslam@...libre.com>
To:     David Lechner <david@...hnology.com>
Cc:     Greg KH <gregkh@...uxfoundation.org>,
        Johan Hovold <johan@...nel.org>, robh+dt@...nel.org,
        Sekhar Nori <nsekhar@...com>,
        Alan Stern <stern@...land.harvard.edu>,
        Kevin Hilman <khilman@...libre.com>,
        Sergei Shtylyov <sshtylyov@...mvista.com>,
        Mark Brown <broonie@...nel.org>,
        Alexandre Bailon <abailon@...libre.com>,
        linux-usb@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH/RFT v2 12/17] USB: ochi-da8xx: Use a regulator for vbus/overcurrent

On Tue, Oct 25, 2016 at 3:39 AM, David Lechner <david@...hnology.com> wrote:
> On 10/24/2016 11:46 AM, ahaslam@...libre.com wrote:
>>
>> From: Axel Haslam <ahaslam@...libre.com>
>>
>> Currently, the da8xx ohci driver uses a set of gpios and callbacks in
>> board files to handle vbus and overcurrent irqs form the power supply.
>> However, this does not play nice when moving to a DT based boot were
>> we wont have board files.
>>
>> Instead of requesting and handling the gpio, use the regulator framework
>> to take care of enabling and disabling vbus power.
>> This has the benefit
>> that we dont need to pass any more platform data to the driver:
>>
>> These will be handled by the regulator framework:
>> set_power   ->  regulator_enable/regulator_disable
>> get_power   ->  regulator_is_enabled
>> get_oci     ->  regulator_get_mode
>> ocic_notify ->  regulator notification
>>
>> We can keep the default potpgt and use the regulator start delay instead:
>> potpgt      -> regulator startup delay time
>>
>> The hawk board does not have a GPIO/OVERCURRENT gpio to control vbus,
>> (they should not have been decleared/reserved) so, just remove those
>> definitions from the hwk board file.
>>
>> Signed-off-by: Axel Haslam <ahaslam@...libre.com>
>> ---
>
>
>
> How do you recover after an overcurrent event?
>
> I have configured a fixed-regulator using device-tree, but similar to the
> configuration in the board files here. However, when I shorted out the VBUS
> and caused an overcurrent event, I see nothing in the kernel log saying that
> there was an overcurrent event and after I remove the short, the regulator
> is never turned back on.
>
>

You should have the patch to fix gpiolib, and you should declare the
over current gpio on the regulator as such:
(if the pin is enabled high you should add oc-active-high);

       vbus_fixed: fixed-regulator-vbus {
               compatible = "regulator-fixed";
               gpio = <&gpio 109 0>;
               oc-gpio = <&gpio 36 0>;
               regulator-boot-on;
               enable-active-high;
               regulator-name = "vbus";
               regulator-min-microvolt = <5000000>;
               regulator-max-microvolt = <5000000>;
       };


Question: Do you see that the over current gpio was requested
in debugfs/gpio? and, do you see the interrupt in /proc/interrupts?

If you unplug and plug in back the usb device it should work again.
also you can unbind and bind it should also start to work:
something like:

echo usb1 >/sys/bus/usb/drivers/usb/unbind
echo usb1 >/sys/bus/usb/drivers/usb/bind


>
>> @@ -163,7 +198,6 @@ static int ohci_da8xx_hub_control(struct usb_hcd *hcd,
>> u16 typeReq, u16 wValue,
>>                                   u16 wIndex, char *buf, u16 wLength)
>>  {
>>         struct device *dev              = hcd->self.controller;
>> -       struct da8xx_ohci_root_hub *hub = dev_get_platdata(dev);
>
>
> nit: unnecessary whitespace change
>
>>         int temp;
>>
>>         switch (typeReq) {
>
>