Hi,
On Fri, Feb 20, 2015 at 11:44:37PM +0800, zhangfei wrote:
> Hi, Balbi
>
> On 02/20/2015 10:41 PM, Felipe Balbi wrote:
>
> >>+static void hi6220_start_peripheral(struct hi6220_priv *priv, bool on)
> >>+{
> >>+ struct usb_otg *otg = priv->phy.otg;
> >>+
> >>+ if (!otg->gadget)
> >>+ return;
> >>+
> >>+ if (on)
> >>+ usb_gadget_connect(otg->gadget);
> >>+ else
> >>+ usb_gadget_disconnect(otg->gadget);
> >
> >why is the PHY fiddling with pullups ?
>
> We use this to enable/disable otg gadget mode.
I got that, but the pullups don't belong to the PHY, they belong to the
gadget.
> The gpio_id & gpio_vbus are used to distinguish otg gadget mode or
> host mode.
> When micro usb or otg device attached to otg, gpio_vbus falling down.
> And gpio_id = 1 is micro usb, gpio_id = 0 is otg device.
all of that I understood clearly :-)
> So when micro usb attached, we enable gadget mode; while micro usb
> detached, we disable gadget mode, and dwc2 will automatically set to
> host mode.
that's all fine, I'm concerned about letting the PHY fiddle with
something it doesn't own. If I am to change pullups rules in udc-core,
this is likely to break down miserably and I don't want to have to go
through that.
> >>+static void hi6220_detect_work(struct work_struct *work)
> >>+{
> >>+ struct hi6220_priv *priv =
> >>+ container_of(work, struct hi6220_priv, work.work);
> >>+ int gpio_id, gpio_vbus;
> >>+ enum usb_otg_state state;
> >>+
> >>+ if (!gpio_is_valid(priv->gpio_id) || !gpio_is_valid(priv->gpio_vbus))
> >>+ return;
> >>+
> >>+ gpio_id = gpio_get_value_cansleep(priv->gpio_id);
> >>+ gpio_vbus = gpio_get_value_cansleep(priv->gpio_vbus);
> >
> >looks like this should be using extcon
> Not used extcon before.
> However, we need gpio_vbus interrupt.
> Checked phy-tahvo.c and phy-omap-otg.c, not find extcon related with
> interrupt.
> Will investigate tomorrow.
drivers/extcon/extcon-gpio.c
> >>+ if (gpio_vbus == 0) {
> >>+ if (gpio_id == 1)
> >>+ state = OTG_STATE_B_PERIPHERAL;
> >>+ else
> >>+ state = OTG_STATE_A_HOST;
> >>+ } else {
> >>+ state = OTG_STATE_A_HOST;
> >>+ }
> >>+
> >>+ if (priv->state != state) {
> >>+ hi6220_start_peripheral(priv, state == OTG_STATE_B_PERIPHERAL);
> >>+ priv->state = state;
> >>+ }
> >>+}
> >>+
> >>+static irqreturn_t hiusb_gpio_intr(int irq, void *data)
> >>+{
> >>+ struct hi6220_priv *priv = (struct hi6220_priv *)data;
> >>+
> >>+ /* add debounce time */
> >>+ schedule_delayed_work(&priv->work, msecs_to_jiffies(100));
> >
> >this is really bad. We have threaded interrupt support, right ?
>
> Since we use two gpio to distinguish gadget mode or host mode.
> Debounce time can introduce more accuracy.
gpio_set_debounce() ?
> I think threaded interrupt can not be used for adding debounce time.
> Here add debounce is just for safety.
add the debounce to the gpio itself.
--
balbi
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