Re: [PATCH v6 07/12] usb: otg: add OTG/dual-role core

From: Peter Chen
Date: Sun Apr 17 2016 - 22:16:56 EST


On Fri, Apr 15, 2016 at 02:00:46PM +0300, Roger Quadros wrote:
> On 15/04/16 12:25, Peter Chen wrote:
> > On Tue, Apr 05, 2016 at 05:05:12PM +0300, Roger Quadros wrote:
> >> + * usb_otg_register() - Register the OTG/dual-role device to OTG core
> >> + * @dev: OTG/dual-role controller device.
> >> + * @config: OTG configuration.
> >> + *
> >> + * Registers the OTG/dual-role controller device with the USB OTG core.
> >> + *
> >> + * Return: struct usb_otg * if success, ERR_PTR() if error.
> >> + */
> >> +struct usb_otg *usb_otg_register(struct device *dev,
> >> + struct usb_otg_config *config)
> >> +{
> >> + struct usb_otg *otg;
> >> + struct otg_wait_data *wait;
> >> + int ret = 0;
> >> +
> >> + if (!dev || !config || !config->fsm_ops)
> >> + return ERR_PTR(-EINVAL);
> >> +
> >> + /* already in list? */
> >> + mutex_lock(&otg_list_mutex);
> >> + if (usb_otg_get_data(dev)) {
> >> + dev_err(dev, "otg: %s: device already in otg list\n",
> >> + __func__);
> >> + ret = -EINVAL;
> >> + goto unlock;
> >> + }
> >> +
> >> + /* allocate and add to list */
> >> + otg = kzalloc(sizeof(*otg), GFP_KERNEL);
> >> + if (!otg) {
> >> + ret = -ENOMEM;
> >> + goto unlock;
> >> + }
> >> +
> >> + otg->dev = dev;
> >> + otg->caps = config->otg_caps;
> >> +
> >> + if ((otg->caps->hnp_support || otg->caps->srp_support ||
> >> + otg->caps->adp_support) && !config->otg_work)
> >> + dev_info(dev, "otg: limiting to dual-role\n");
> >
> > What does above mean? Customized otg_work item may be dual-role,
> > may be full otg.
>
> I'm checking for !config->otg_work so we're sure of using the
> default dual-role only work function.
>

I see. But whether it is dual-role or fully otg should depend on
otg->caps, the work item may be different according to design.
Besides, your code seems to depend on one of the otg capabilities
for dual-role.

--

Best Regards,
Peter Chen