Re: [PATCH v1 2/6] usb: otg: utils: add facilities in phy lib to support multiple PHYs of same type

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Hi,

On Tuesday 22 January 2013 07:37 PM, Roger Quadros wrote:
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@xxxxxx>
---
  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?

Good catch. I'll update the patch.

Thanks
Kishon
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