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    SubjectRe: [PATCH v4 10/15] usb: phy: msm: Add device tree support and binding information
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    Hi, 

    On Thu, 2013-12-05 at 10:41 +0000, Mark Rutland wrote:
    > On Mon, Nov 18, 2013 at 12:54:37PM +0000, Ivan T. Ivanov wrote:
    > > Hi Mark,
    > >
    > > On Fri, 2013-11-15 at 16:38 +0000, Mark Rutland wrote:
    > > > On Tue, Nov 12, 2013 at 02:51:45PM +0000, Ivan T. Ivanov wrote:
    > > > > From: "Ivan T. Ivanov" <iivanov@mm-sol.com>
    > > > >
    > > > > Allows MSM OTG controller to be specified via device tree.
    > > > >
    > > > > Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
    > > > > Cc: devicetree@vger.kernel.org
    > > > > ---
    > > > > .../devicetree/bindings/usb/msm-hsusb.txt | 57 +++++++++++++-
    > > > > drivers/usb/phy/phy-msm-usb.c | 79 +++++++++++++++++---
    > > > > 2 files changed, 124 insertions(+), 12 deletions(-)
    >
    > [...]
    >
    > > > > +
    > > > > +- dr_mode: One of "host", "peripheral" or "otg". Defaults to "otg"
    > > >
    > > > If this has a default and thus isn't required, it should be listed as
    > > > optional.
    > >
    > > This is part of the standard USB bindings, Perhaps I could just
    > > refer to: Documentation/devicetree/bindings/usb/generic.txt
    >
    > That would be fine, but it should also be moved to the optional
    > properties section.

    Ok.

    >
    > >
    > >
    > > >
    > > > > +
    > > > > +- vdccx-supply: phandle to the regulator for the vdd supply for
    > > > > + digital circuit operation.
    > > > > +- v1p8-supply: phandle to the regulator for the 1.8V supply
    > > > > +- v3p3-supply: phandle to the regulator for the 3.3V supply
    > > > > +
    > > > > +- qcom,otg-control: OTG control (VBUS and ID notifications) can be one of
    > > > > + 1 - PHY control
    > > > > + 2 - PMIC control
    > > > > + 3 - User control (via debugfs)
    > > >
    > > > NAK. This does not seem like a description of the hardware, and given
    > > > the debugfs comment is fundamentally tied to the way Linux functions
    > > > today.
    > >
    > > I will remove option 3, but rest are really property of the chipset.
    >
    > Can you elaborate on the diffence please?

    Difference is how VBUS, ID changes, Accessory and Charger
    detection is handled. In older chips-sets they are handled
    by PHY controller, while now they are handled by external
    PMIC logic.

    >
    > >
    > > >
    > > > > +
    > > > > +Optional properties:
    > > > > +- qcom,phy-init-sequence: PHY configuration sequence. val, reg pairs
    > > > > + terminate with -1
    > > >
    > > > What is this? I'm really not keen on having arbitrary register/memory
    > > > poking sequences in the dt.
    > >
    > > This is related Device Mode Eye Diagram test and values used could be
    > > different between chipsets.
    >
    > Ok. Then we should encode the tuning data rather than adding a mechanism
    > to allow for writes to arbitrary addresses.

    Currently:

    for msm8226 sequence is < 0x44 0x80 0x68 0x81 0x24 0x82 0x13 0x83 >
    for msm8974 sequence is < 0x63 0x81 >

    I could reserve -1 as "do not program" value and document that
    values in this array will be written to ULPI interface with
    ULPI_EXT_VENDOR_SPECIFIC as base address.

    for msm8974 sequence will be < -1 0x63 >

    >
    > >
    > > >
    > > > Why does it need to be terminated? Surely the size of the property tells
    > > > you that it's terminated.
    > >
    > > Yes. -1 termination could be done in driver.
    >
    > Please do. There's no need for it to be in the DT.


    Thanks. Ivan

    >
    > Cheers,
    > Mark.
    > --
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