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SubjectRe: [PATCH v1 2/6] usb: otg: utils: add facilities in phy lib to support multiple PHYs of same type
On 01/22/2013 11:58 AM, Kishon Vijay Abraham I wrote:
> In order to add support for multipe PHY's of the same type, new API's
> for adding PHY and getting PHY has been added. Now the binding
> information for the PHY and controller should be done in platform file
> using usb_bind_phy API. And for getting a PHY, the device pointer of the
> USB controller and an index should be passed. Based on the binding
> information that is added in the platform file, usb_get_phy_dev will return the
> appropriate PHY.
> Already existing API's to add and get phy by type is not removed. These
> API's are deprecated and will be removed once all the platforms start to
> use the new API.
>
> Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
> ---
> drivers/usb/otg/otg.c | 114 ++++++++++++++++++++++++++++++++++++++++++++++-
> include/linux/usb/phy.h | 13 ++++++
> 2 files changed, 126 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/otg/otg.c b/drivers/usb/otg/otg.c
> index 492ba2f..1f30b22 100644
> --- a/drivers/usb/otg/otg.c
> +++ b/drivers/usb/otg/otg.c
> @@ -36,6 +36,20 @@ static struct usb_phy *__usb_find_phy(struct list_head *list,
> return ERR_PTR(-ENODEV);
> }
>
> +static struct usb_phy *__usb_find_phy_dev(struct device *dev,
> + struct list_head *list, u8 index)
> +{
> + struct usb_phy_bind *phy_bind = NULL;
> +
> + list_for_each_entry(phy_bind, list, list) {
> + if (!(strcmp(phy_bind->dev_name, dev_name(dev))) &&
> + phy_bind->index == index)
> + return phy_bind->phy;

If the PHY driver has not yet called usb_add_phy_dev() (e.g. driver not yet loaeded)
then this will return NULL.

> + }
> +
> + return ERR_PTR(-ENODEV);
> +}
> +
> static void devm_usb_phy_release(struct device *dev, void *res)
> {
> struct usb_phy *phy = *(struct usb_phy **)res;
> @@ -112,6 +126,69 @@ err0:
> EXPORT_SYMBOL(usb_get_phy);
>
> /**
> + * usb_get_phy_dev - find the USB PHY
> + * @dev - device that requests this phy
> + * @index - the index of the phy
> + *
> + * Returns the phy driver, after getting a refcount to it; or
> + * -ENODEV if there is no such phy. The caller is responsible for
> + * calling usb_put_phy() to release that count.
> + *
> + * For use by USB host and peripheral drivers.
> + */
> +struct usb_phy *usb_get_phy_dev(struct device *dev, u8 index)
> +{
> + struct usb_phy *phy = NULL;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&phy_lock, flags);
> +
> + phy = __usb_find_phy_dev(dev, &phy_bind_list, index);
> + if (IS_ERR(phy)) {
> + pr_err("unable to find transceiver\n");
> + goto err0;
> + }

Since NULL is not IS_ERR(), you will do a NULL pointer reference below.

In such cases we would want to use the deferred probe mechanism. So should we return
-EPROBE_DEFER?

> +
> + get_device(phy->dev);
> +
> +err0:
> + spin_unlock_irqrestore(&phy_lock, flags);
> +
> + return phy;
> +}
> +EXPORT_SYMBOL(usb_get_phy_dev);
> +

--
cheers,
-roger


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