Hello.
On 06/25/2014 12:44 PM, Vivek Gautam wrote:
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 9ffecd5..453d89e 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1582,6 +1582,9 @@ struct xhci_hcd {
u32 port_status_u0;
/* Compliance Mode Timer Triggered every 2 seconds */
#define COMP_MODE_RCVRY_MSECS 2000
+ /* phys for the controller */
+ struct phy *phy2_gen;
+ struct phy *phy3_gen;
};
I don't think adding new variables here and restricting most of this
logic to xhci-plat.c (in the next patch) is the best way to do it.
Indeed.
Actually, I haven't given enough thought to this...
There's no conceptual reason why other host controllers (e.g. xhci-pci
or even EHCI) could not have a similar need to tune their PHY after
reset. PHYs are universal to all host controllers.
There is already a 'phy' member in struct usb_hcd which I think is
mostly unused right now. I think it would be much less
confusing/redundant to reuse that member for this purpose (you could
still set it up from xhci_plat_probe(), and then call it from
hcd_bus_resume() or something like that).
That member has type 'struct usb_phy *' while here we have 'struct phy *'
-- feel the difference.
I have already tried adding 'struct phy *gen_phy' to 'struct usb_hcd',
So the 'struct phy *' available in the usb_hcd is requested in usb_add_hcd().
This is requested with the constant string 'usb' :
struct phy *phy = phy_get(hcd->self.controller, "usb");
This can get the phy with string 'usb' only if, either the host
controller has a device node wherein the phys are given.
Yes, that was the plan. Currently, the PHY driver for which this was
written can be probed from the device tree only.
Even in this case one can't give same constant string for two
different phys, UTMI+ and PIPE3 phy, isn't it ?
Yes, you're right. I didn't really consider the case of some host needing
2 distinct PHY.
Or, the other way can be when host gets a lookup table to look into to
find the relevant phys, something like
Heikki has suggested:
usb: dwc3: host: convey the PHYs to xhci
(https://lkml.org/lkml/2014/6/5/585) and related patch series.
Well, AFAIK the look-up table method is already provided by the current
PHY core for non-DT use cases; this doesn't seem to have changed with that
patch set, does it?
So if we use this second approach, we would need to override the
'phy_get()' that has been done in usb_add_hcd()
in xhci_plat_probe(), and then use them in later operations.
I guess it'd probably be simpler to ignore the 'gen_phy' member of 'struct
usb_hcd' in your case (if it gets eventually added).
WBR, Sergei
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