[PATCH v2 03/22] usb: ulpi: Support device discovery via device properties

Stephen Boyd
2016-08-05T21:27:35Z

Quoting Peter Chen (2016-07-08 02:04:58)
> On Thu, Jul 07, 2016 at 03:20:54PM -0700, Stephen Boyd wrote:
> > @@ -39,6 +42,10 @@ static int ulpi_match(struct device *dev, struct device_driver *driver)
> > struct ulpi *ulpi = to_ulpi_dev(dev);
> > const struct ulpi_device_id *id;
> >
> > + /* Some ULPI devices don't have a product id so rely on OF match */
> > + if (ulpi->id.product == 0)
> > + return of_driver_match_device(dev, driver);
> > +
>
> How about using vendor id? It can't be 0, but pid may be 0.
> See: http://www.linux-usb.org/usb.ids

Heikki suggested a product id of 0 would mean we need to use DT
matching. Should it be changed to vendor id instead?

>
> > +static int ulpi_of_register(struct ulpi *ulpi)
> > +{
> > + struct device_node *np = NULL, *child;
> > +
> > + /* Find a ulpi bus underneath the parent or the parent of the parent */
> > + if (ulpi->dev.parent->of_node)
> > + np = of_find_node_by_name(ulpi->dev.parent->of_node, "ulpi");
> > + else if (ulpi->dev.parent->parent && ulpi->dev.parent->parent->of_node)
> > + np = of_find_node_by_name(ulpi->dev.parent->parent->of_node,
> > + "ulpi");
> > + if (!np)
> > + return 0;
> > +
> > + child = of_get_next_available_child(np, NULL);
> > + if (!child)
> > + return -EINVAL;
>
> You may need to call of_node_put on parent (np), not on child node
> below.

Fixed, thanks.

>
> > +
> > + ulpi->dev.of_node = child;
> > +
> > + return 0;
> > +}
> > +
> > +static int ulpi_read_id(struct ulpi *ulpi)
> > {
> > int ret;
> >
> > @@ -174,14 +218,39 @@ static int ulpi_register(struct device *dev, struct ulpi *ulpi)
> > ulpi->id.product = ulpi_read(ulpi, ULPI_PRODUCT_ID_LOW);
> > ulpi->id.product |= ulpi_read(ulpi, ULPI_PRODUCT_ID_HIGH) << 8;
> >
> > + return 0;
> > +}
> > +
>
> What does this API for? Why it still needs to be called after
> vid/pid gets from firmware?

Ideally we get the vid/pid from the ULPI registers instead of from
firmware. So we typically want to call ulpi_read_id() because most
likely the ulpi-vendor and ulpi-product properties are missing.