On 01/21/2013 03:34 PM, kishon wrote:
> On Monday 21 January 2013 06:51 PM, Roger Quadros wrote:
>> On 01/16/2013 05:01 PM, Kishon Vijay Abraham I wrote:
>>> Added an API devm_usb_get_phy_by_phandle(), to get usb phy by passing a
>>> device node phandle value. This function will return a pointer to
>>> the phy on success, -EPROBE_DEFER if there is a device_node for the
>>> phandle,
>>> but the phy has not been added, or a ERR_PTR() otherwise.
>>>
>>> Cc: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
>>> Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx>
>>> ---
>>> drivers/usb/otg/otg.c | 77
>>> +++++++++++++++++++++++++++++++++++++++++++++++
>>> include/linux/usb/phy.h | 8 +++++
>>> 2 files changed, 85 insertions(+)
>>>
>>> diff --git a/drivers/usb/otg/otg.c b/drivers/usb/otg/otg.c
>>> index dbf2043..e9799bb 100644
>>> --- a/drivers/usb/otg/otg.c
>>> +++ b/drivers/usb/otg/otg.c
>>> @@ -13,7 +13,9 @@
>>> #include <linux/export.h>
>>> #include <linux/err.h>
>>> #include <linux/device.h>
>>> +#include <linux/module.h>
>>> #include <linux/slab.h>
>>> +#include <linux/of.h>
>>>
>>> #include <linux/usb/otg.h>
>>>
>>> @@ -34,6 +36,20 @@ static struct usb_phy *__usb_find_phy(struct
>>> device *dev, u8 index)
>>> return ERR_PTR(-ENODEV);
>>> }
>>>
>>> +static struct usb_phy *__of_usb_find_phy(struct device_node *node)
>>> +{
>>> + struct usb_phy *phy;
>>> +
>>> + list_for_each_entry(phy, &phy_list, head) {
>>> + if (node != phy->dev->of_node)
>>> + continue;
>>> +
>>> + return phy;
>>> + }
>>> +
>>> + return ERR_PTR(-ENODEV);
>>> +}
>>> +
>>> static void devm_usb_phy_release(struct device *dev, void *res)
>>> {
>>> struct usb_phy *phy = *(struct usb_phy **)res;
>>> @@ -109,6 +125,67 @@ err0:
>>> }
>>> EXPORT_SYMBOL(usb_get_phy);
>>>
>>> + /**
>>> + * devm_usb_get_phy_by_phandle - find the USB PHY by phandle
>>> + * @dev - device that requests this phy
>>> + * @phandle - name of the property holding the phy phandle value
>>> + * @index - the index of the phy
>>> + *
>>> + * Returns the phy driver associated with the given phandle value,
>>> + * after getting a refcount to it, -ENODEV if there is no such phy or
>>> + * -EPROBE_DEFER if there is a phandle to the phy, but the device is
>>> + * not yet loaded. While at that, it also associates the device with
>>> + * the phy using devres. On driver detach, release function is invoked
>>> + * on the devres data, then, devres data is freed.
>>> + *
>>> + * For use by USB host and peripheral drivers.
>>> + */
>>> +struct usb_phy *devm_usb_get_phy_by_phandle(struct device *dev,
>>> + const char *phandle, u8 index)
>>> +{
>>> + struct usb_phy *phy = NULL, **ptr;
>>> + unsigned long flags;
>>> + struct device_node *node;
>>> +
>>> + if (!dev->of_node) {
>>> + dev_dbg(dev, "device does not have a device node entry\n");
>>> + return ERR_PTR(-EINVAL);
>>> + }
>>> +
>>> + node = of_parse_phandle(dev->of_node, phandle, index);
>>> + if (!node) {
>>> + dev_dbg(dev, "failed to get %s phandle in %s node\n", phandle,
>>> + dev->of_node->full_name);
>>> + return ERR_PTR(-ENODEV);
>>> + }
>>> +
>>> + ptr = devres_alloc(devm_usb_phy_release, sizeof(*ptr), GFP_KERNEL);
>>> + if (!ptr) {
>>> + dev_dbg(dev, "failed to allocate memory for devres\n");
>>> + return ERR_PTR(-ENOMEM);
>>> + }
>>
>> I fail to understand why you need ptr at all and why do devres_alloc()
>> for it.
>
> Thats how we create a "managed device resource". You can have a look at
> Documentation/driver-model/devres.txt and drivers/base/devres.c.
OK, I get it now. You might want to update the text file too since you
are adding a automagically managed interface.
regards,
-roger
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