Re: [PATCH RFC 3/4] xhci: Tune PHY for the DWC3-Exynos host controller

From: Vivek Gautam
Date: Tue Apr 15 2014 - 08:54:29 EST


Hi Heikki,


On Tue, Dec 10, 2013 at 7:25 PM, Heikki Krogerus
<heikki.krogerus@xxxxxxxxxxxxxxx> wrote:

Giving life to this thread after long time.

> Hi,
>
> On Tue, Dec 10, 2013 at 04:25:25PM +0530, Vivek Gautam wrote:
>> @@ -170,6 +189,15 @@ static int xhci_plat_probe(struct platform_device *pdev)
>> }
>>
>> /*
>> + * The parent of the xhci-plat device may pass in a PHY via
>> + * platform data. If it exists, store it in our struct usb_hcd
>> + * so that we can use it later.
>> + */
>> + phy_generic = dev_get_platdata(&pdev->dev);
>> + if (phy_generic)
>> + xhci->shared_hcd->phy_generic = *phy_generic;
>
> Getting the handle to the phy from platform data like this is not
> going to work for long. It should be possible to get it normally with
> phy_get(). It's not going to be possible to get the handle from the
> platform data like this if the xhci-hcd platform device is created
> from ACPI or DT. You are also not considering case where you have two
> phys.
>
> Vivek, I have made a patch set for the phy framework allowing
> associations between the phys and their users to be made in same way
> gpios and clk make them. With those you should be able to create a
> lookup entry to the phy framework in drivers/usb/dwc3/host.c. Then we
> could use phy_get() here already. Please check them. Subject of the
> thread:
>
> "phy: remove the need for the phys to know about their users"

I had seen your patches in the mailing list, but i don't see any
updated version of these patches.
Are you planning to work on this above mentioned patch-series any time soon ?

Or, should i try to find a different approach for handling the phy
from the host controller (child of DWC3 in this case, which has the
phys).

>
> The lookup table can then be added in drivers/usb/dwc3/host.c with
> something like this:
>
> int dwc3_host_init(struct dwc3 *dwc)
> {
> struct platform_device *xhci;
> struct phy_lookup_table *table;
> ...
> table->dev_id = dev_name(&xhci->dev);
> if (dwc->usb2_generic_phy)
> table->table[0].phy_name = dev_name(&dwc->usb2_generic_phy->dev);
> if (dwc->usb3_generic_phy)
> table->table[1].phy_name = dev_name(&dwc->usb3_generic_phy->dev);
> phy_add_lookup_table(table);
> ...
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