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Date:   Fri, 13 Jan 2023 13:44:34 +0100
Message-Id: <CPR2LS3SJQ3I.Z7UY505COG3@otso>
Cc:     <linux-arm-msm@vger.kernel.org>,
        <~postmarketos/upstreaming@lists.sr.ht>,
        <phone-devel@vger.kernel.org>, "Andy Gross" <agross@kernel.org>,
        "Bjorn Andersson" <andersson@kernel.org>,
        "Konrad Dybcio" <konrad.dybcio@linaro.org>,
        "Kishon Vijay Abraham I" <kishon@kernel.org>,
        <linux-phy@lists.infradead.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 2/3] phy: qcom-qmp-combo: Add config for SM6350
From:   "Luca Weiss" <luca.weiss@fairphone.com>
To:     "Dmitry Baryshkov" <dmitry.baryshkov@linaro.org>,
        "Vinod Koul" <vkoul@kernel.org>, "Johan Hovold" <johan@kernel.org>
References: <20221130081430.67831-1-luca.weiss@fairphone.com>
 <20221130081430.67831-2-luca.weiss@fairphone.com>
 <Y6xP4YRAp68TfxFi@hovoldconsulting.com> <Y8BIX+js1ircJyb9@matsya>
 <cf968a25-02f7-d402-530b-eb379b707e54@linaro.org>
In-Reply-To: <cf968a25-02f7-d402-530b-eb379b707e54@linaro.org>
Precedence: bulk

Hi Dmitry,

On Thu Jan 12, 2023 at 8:33 PM CET, Dmitry Baryshkov wrote:
> On 12/01/2023 19:50, Vinod Koul wrote:
> > On 28-12-22, 15:17, Johan Hovold wrote:
> >> Luca, Vinod,
> >>
> >> On Wed, Nov 30, 2022 at 09:14:28AM +0100, Luca Weiss wrote:
> >>> Add the tables and config for the combo phy found on SM6350.
> >>>
> >>> Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
> >>> ---
> >>> Changes since v2:
> >>> * Drop dp_txa/dp_txb changes, not required
> >>> * Fix dp_dp_phy offset
> >>>
> >>>   drivers/phy/qualcomm/phy-qcom-qmp-combo.c | 126 +++++++++++++++++++=
+++
> >>>   1 file changed, 126 insertions(+)
> >>>
> >>> diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-combo.c b/drivers/phy/=
qualcomm/phy-qcom-qmp-combo.c
> >>> index 77052c66cf70..6ac0c68269dc 100644
> >>> --- a/drivers/phy/qualcomm/phy-qcom-qmp-combo.c
> >>> +++ b/drivers/phy/qualcomm/phy-qcom-qmp-combo.c
> >>
> >>> @@ -975,6 +1039,19 @@ static const char * const sc7180_usb3phy_reset_=
l[] =3D {
> >>>   	"phy",
> >>>   };
> >>>  =20
> >>> +static const struct qmp_combo_offsets qmp_combo_offsets_v3 =3D {
> >>> +	.com		=3D 0x0000,
> >>> +	.txa		=3D 0x1200,
> >>> +	.rxa		=3D 0x1400,
> >>> +	.txb		=3D 0x1600,
> >>> +	.rxb		=3D 0x1800,
> >>> +	.usb3_serdes	=3D 0x1000,
> >>> +	.usb3_pcs_misc	=3D 0x1a00,
> >>> +	.usb3_pcs	=3D 0x1c00,
> >>> +	.dp_serdes	=3D 0x1000,
> >>
> >> I would have expected this to be 0x2000 as that's what the older
> >> platforms have been using for the dp serdes table so far. Without acce=
ss
> >> to any documentation it's hard to tell whether everyone's just been
> >> cargo-culting all along or if there's actually something there at offs=
et
> >> 0x2000.
>
> usb3_serdes is 0x1000, so dp_serdes equal to 0x1000 is definitely an typo=
.
>
> Judging from the downstream dtsi, the DP PHY starts at offset 0x2000. So=
=20
> dp_serdes is equal to 0x2000, dp_phy =3D 0x2a00, ln_tx1 =3D 0x2200, ln_tx=
2 =3D=20
> 0x2600.

Can you share how you got to the 0x2000 offset? You can see my
(potentially wrong) reasoning for 0x1000 a few messages ago[0].

The only 0x2000-something I could find now while looking at it again is
"#define USB3_DP_PHY_DP_DP_PHY_PD_CTL 0x2a18" which becomes
USB3_DP_DP_PHY_PD_CTL in the driver but this is seemingly not used at
all in my msm-4.19 tree.

Also if you have any idea on how to test it at runtime without actually
having to get all the type-C functionality up I'd be happy to try that.
Unfortunately I believe there's still quite some bits missing to
actually get DP out via the USB-C port - which I imagine would trigger
the PHY setup.

[0] https://lore.kernel.org/linux-arm-msm/CPDIYQ3SSY3E.I0Y0NMIED0WO@otso/

Regards
Luca

>
> >>
> >> Vinod, could you shed some light on this as presumably you have access
> >> to some documentation?
> >>
> >>> +	.dp_dp_phy	=3D 0x2a00,
> >=20
> > No sorry, I dont have access to this version...
> >=20
>
> --=20
> With best wishes
> Dmitry