Re: [PATCH v6] usb: gadget: mv: Add USB 3.0 device driver for Marvell PXA2128 chip.

[Yu Xu <yuxu42@xxxxxxxxx>]

Hi Balbi,

2012/6/15 Felipe Balbi <balbi@xxxxxx>:
> Hi,
>
> On Wed, Jun 06, 2012 at 04:21:59PM +0800, Yu Xu wrote:
>> +static int mv_u3d_start(struct usb_gadget *g,
>> +             struct usb_gadget_driver *driver)
>> +{
>> +     struct mv_u3d *u3d = container_of(g, struct mv_u3d, gadget);
>> +     unsigned long flags;
>> +
>> +     if (u3d->driver)
>> +             return -EBUSY;
>> +
>> +     spin_lock_irqsave(&u3d->lock, flags);
>> +
>> +     /* hook up the driver ... */
>> +     driver->driver.bus = NULL;
>> +     u3d->driver = driver;
>> +     u3d->gadget.dev.driver = &driver->driver;
>> +
>> +     u3d->ep0_dir = USB_DIR_OUT;
>> +
>> +     spin_unlock_irqrestore(&u3d->lock, flags);
>> +
>> +     u3d->vbus_valid_detect = 1;
>> +
>> +     return 0;
>> +}
>> +
>> +static int mv_u3d_stop(struct usb_gadget *g,
>> +             struct usb_gadget_driver *driver)
>> +{
>> +     struct mv_u3d *u3d = container_of(g, struct mv_u3d, gadget);
>> +     unsigned long flags;
>> +
>> +     u3d->vbus_valid_detect = 0;
>> +     spin_lock_irqsave(&u3d->lock, flags);
>> +
>> +     mv_u3d_enable(u3d);
>> +     mv_u3d_controller_stop(u3d);
>> +     /* stop all usb activities */
>> +     u3d->gadget.speed = USB_SPEED_UNKNOWN;
>> +     mv_u3d_stop_activity(u3d, driver);
>> +     mv_u3d_disable(u3d);
>> +
>> +     spin_unlock_irqrestore(&u3d->lock, flags);
>> +
>> +     u3d->gadget.dev.driver = NULL;
>> +     u3d->driver = NULL;
>> +
>> +     return 0;
>> +}
>
> the whole idea of udc_start() and udc_stop() is that you only power up
> your controller when you know that you will need it. So on driver probe
> you shouldn't really enable your clocks or configure anything and
> instead, should move it all here. This is exactly the place you know
> your controller will be needed, because you're probing a gadget driver.
>
> Other that that, it's all good.
>
We enable clock to access the usb controller register to read the address of
op_regs and uvc_regs, and store to the mv_u3d structure. Then we disable
clock. This is the only purpose of clock enable/disable in probe, but not intend
to enable and configure usb controller in probe:)

> --
> balbi

Thanks,
Yu Xu
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