Hi Alan,
On Mon, Feb 12, 2018 at 4:15 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
> On Sun, 11 Feb 2018, Martin Blumenstingl wrote:
>
>> The USB HCD core driver parses the device-tree node for "phys" and
>> "usb-phys" properties. It also manages the power state of these PHYs
>> automatically.
>> However, drivers may opt-out of this behavior by setting "phy" or
>> "usb_phy" in struct usb_hcd to a non-null value. An example where this
>> is required is the "Qualcomm USB2 controller", implemented by the
>> chipidea driver. The hardware requires that the PHY is only powered on
>> after the "reset completed" event from the controller is received.
>>
>> A follow-up patch will allow the USB HCD core driver to manage more than
>> one PHY. Add a new "bool skip_phy_initialization" field to struct
>> usb_hcd so drivers can opt-out of any PHY management provided by the USB
>> HCD core driver. The new field will be used in that patch as well.
>>
>> This also updates the existing drivers so they use the new flag if they
>> want to opt out of the PHY management provided by the USB HCD core
>> driver. This means that for these drivers the new "multiple PHY"
>> handling (which will be added in a follow-up patch) will be disabled as
>> well.
>>
>> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
>> ---
>
>> --- a/include/linux/usb/hcd.h
>> +++ b/include/linux/usb/hcd.h
>> @@ -98,6 +98,12 @@ struct usb_hcd {
>> */
>> const struct hc_driver *driver; /* hw-specific hooks */
>>
>> + /*
>> + * do not manage the PHY state in the HCD core, instead let the driver
>> + * handle this (for example if the PHY can only be turned on after a
>> + * specific event)
>> + */
>> + bool skip_phy_initialization;
>
> Instead of declaring this as a bool at some random location in the
> structure, it would be better to make this a bitflag along with the
> other ones that get set at registration. For example, it could come
> right after the remove_phy flag.
I'll move it to the other bitflags as suggested - thanks for pointing this out!
just to save you from reviewing this over and over again:
- I'll move the skip_phy_initialization field below remove_phy
- it's new definition will be "unsigned skip_phy_initialization:1"
- do you see any issues with the rest of the patch (the "concept" of
using a flag to skip all kinds of PHY initialization)?
Regards
Martin
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