From: Alan Stern <stern-nwvwT67g6+6dFdvTe/nMLpVzexx5G7lz@public.gmane.org>
To: Martin Blumenstingl
<martin.blumenstingl-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>
Cc: linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
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Subject: Re: [PATCH usb-next v9 2/8] usb: add a flag to skip PHY initialization to struct usb_hcd
Date: Mon, 12 Feb 2018 10:15:40 -0500 (EST) [thread overview]
Message-ID: <Pine.LNX.4.44L0.1802121013360.1411-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <20180211210651.2046-3-martin.blumenstingl-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>
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-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>
> ---
> --- 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.
Alan Stern
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next prev parent reply other threads:[~2018-02-12 15:15 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-11 21:06 [PATCH usb-next v9 0/8] initialize (multiple) PHYs for a HCD Martin Blumenstingl
[not found] ` <20180211210651.2046-1-martin.blumenstingl-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>
2018-02-11 21:06 ` [PATCH usb-next v9 1/8] dt-bindings: usb: add the documentation for USB HCDs Martin Blumenstingl
2018-02-11 21:06 ` [PATCH usb-next v9 2/8] usb: add a flag to skip PHY initialization to struct usb_hcd Martin Blumenstingl
[not found] ` <20180211210651.2046-3-martin.blumenstingl-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>
2018-02-12 15:15 ` Alan Stern [this message]
[not found] ` <Pine.LNX.4.44L0.1802121013360.1411-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2018-02-12 19:25 ` Martin Blumenstingl
[not found] ` <CAFBinCBnea-Nt73Lz6K+hKub++Upxa6ot8o857rG3GeuLugZYw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2018-02-12 19:42 ` Alan Stern
2018-02-11 21:06 ` [PATCH usb-next v9 3/8] usb: core: add a wrapper for the USB PHYs on the HCD Martin Blumenstingl
2018-02-11 21:06 ` [PATCH usb-next v9 4/8] usb: core: hcd: integrate the PHY wrapper into the HCD core Martin Blumenstingl
2018-02-11 21:06 ` [PATCH usb-next v9 5/8] usb: host: xhci-mtk: remove custom USB PHY handling Martin Blumenstingl
2018-02-11 21:06 ` [PATCH usb-next v9 6/8] usb: host: ehci-platform: " Martin Blumenstingl
2018-02-11 21:06 ` [PATCH usb-next v9 7/8] usb: host: ohci-platform: " Martin Blumenstingl
2018-02-11 21:06 ` [PATCH usb-next v9 8/8] usb: core: hcd: remove support for initializing a single PHY Martin Blumenstingl
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