Re: [PATCH] phy: omap-usb2: add explicit PHY comparator API

[Vinod Koul <vkoul@kernel.org>]

On 31-08-26, 19:14, Ivaylo Dimitrov wrote:
> 
> 
> On 27.08.26 г. 18:51 ч., Vinod Koul wrote:
> > On 22-07-26, 08:36, Ivaylo Dimitrov wrote:
> > > The existing omap_usb2_set_comparator() API locates the OMAP USB2 PHY
> > > instance by calling usb_get_phy(USB_PHY_TYPE_USB2), assuming there is a
> > > single USB2 PHY registered in the system.
> > > 
> > > This assumption no longer holds on systems with multiple USB2 PHY
> > > providers. In such cases, the global lookup may return a different USB2
> > > PHY instance, causing the OMAP driver to perform an invalid container_of()
> > > conversion when accessing its private data.
> > > 
> > > Introduce omap_usb2_set_phy_comparator(), allowing callers to explicitly
> > > specify the OMAP USB2 PHY instance to associate with a phy_companion.
> > > The new helper validates that the supplied USB PHY is an OMAP USB2 PHY
> > > before accessing its private data.
> > 
> > Well the name can cause ambiguity with old API. Second I would like to
> > see users of this API as well
> > 
> 
> Would `omap_usb2_set_comparator_for_phy()` be clearer? Or could you
> suggest a better name?

Yes that would be okay

> Regarding the user of the API, let me provide some background.
> 
> Currently, the cpcap-charger driver uses the old omap_usb2_set_comparator()
> API. On mapphone devices there are two
> USB-PHY devices, phy_omap_usb2 and phy_cpcap_usb. The old API selects
> the first USB2 PHY probed, which is not guaranteed to be the OMAP PHY.
> 
> I have also added DCP detection and extcon support to the CPCAP PHY, and
> I'm working on proper charging current limiting in cpcap-charger. For that,
> the charger driver needs to be able to explicitly select the OMAP
> PHY from DT and register for its PHY events, in order to properly limit
> the current in case of DCP/gadget/OTG connection.
> 
> With the DT configuration, cpcap-charger has the specific PHY instance
> available and can use the new API. For legacy configurations without a
> PHY specified in DT, it will continue to use the existing API.
> 
> The relevant changes are:
> 
> DCP detection/extcon support in the CPCAP PHY:
> https://lkml.org/lkml/2026/7/11/600
> 
> `cpcap-charger` changes (currently out-of-tree):
> https://git.maemo.org/leste-upstream-forks/droid4-linux/commit/0261cbb724d875ee4aa2e5af34caead39e5e47fb
> 
> I initially kept the cpcap-charger change separate since the two
> patches look somewhat unrelated. I also wanted to see whether the
> approach in this patch is acceptable in principle before preparing the
> cpcap-charger changes for upstreaming.
> 
> Would you prefer me to send a series with the $subject patch and the
> cpcap-charger changes, including the required DT schema changes?
> 
> Thanks and regards,
> Ivo
> 

-- 
~Vinod

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