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From:   Miao-chen Chou <mcchou@chromium.org>
Date:   Mon, 9 May 2022 20:17:13 -0700
Message-ID: <CABmPvSFiAC474WthmMX0nE20UEOxUD5dEYBVbiKh7HOovCnCkA@mail.gmail.com>
Subject: Re: [PATCH v1 3/3] Bluetooth: hci_qca: WAR to handle WCN6750 HW issue
To:     "Balakrishna Godavarthi (QUIC)" <quic_bgodavar@quicinc.com>
Cc:     Marcel Holtmann <marcel@holtmann.org>,
        Andy Gross <agross@kernel.org>,
        "robh+dt@kernel.org" <robh+dt@kernel.org>,
        "bjorn.andersson@linaro.org" <bjorn.andersson@linaro.org>,
        "linux-arm-msm@vger.kernel.org" <linux-arm-msm@vger.kernel.org>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        "mka@chromium.org" <mka@chromium.org>,
        "linux-bluetooth@vger.kernel.org" <linux-bluetooth@vger.kernel.org>,
        "Hemant Gupta (QUIC)" <quic_hemantg@quicinc.com>,
        "Sai Teja Aluvala (Temp) (QUIC)" <quic_saluvala@quicinc.com>,
        quic_rjliao <quic_rjliao@quicinc.com>,
        Alain Michaud <alainmichaud@google.com>,
        Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
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Hi Bala,

When is the estimated start date and timeline of the driver development?

Thanks,
Miao

On Fri, Apr 29, 2022 at 8:09 PM Balakrishna Godavarthi (QUIC)
<quic_bgodavar@quicinc.com> wrote:
>
> Hi Marcel,
>
> -----Original Message-----
> From: Marcel Holtmann <marcel@holtmann.org>
> Sent: Friday, April 29, 2022 8:24 PM
> To: Balakrishna Godavarthi (QUIC) <quic_bgodavar@quicinc.com>
> Cc: Andy Gross <agross@kernel.org>; robh+dt@kernel.org; bjorn.andersson@l=
inaro.org; linux-arm-msm@vger.kernel.org; devicetree@vger.kernel.org; linux=
-kernel@vger.kernel.org; Johan Hedberg <johan.hedberg@gmail.com>; mka@chrom=
ium.org; linux-bluetooth@vger.kernel.org; Hemant Gupta (QUIC) <quic_hemantg=
@quicinc.com>; Sai Teja Aluvala (Temp) (QUIC) <quic_saluvala@quicinc.com>; =
quic_rjliao <quic_rjliao@quicinc.com>; mcchou@chromium.org
> Subject: Re: [PATCH v1 3/3] Bluetooth: hci_qca: WAR to handle WCN6750 HW =
issue
>
> Hi Balakrishna,
>
> > The patch is workaround for hardware issue on WCN6750.
> > On WCN6750 sometimes observed AON power source takes 100ms time to
> > fully discharge voltage during OFF. As WCN6750 is combo chip for WLAN
> > and BT. If any of the tech area ON is triggered during discharge
> > phase, it fails to turn ON.
> > To overcome this hardware issue, During BT ON, driver check for
> > WLAN_EN pin status. If it high, it will pull BT_EN to high immediately
> > else it will wait for 100ms assuming WLAN was just powered OFF and
> > then BT_EN will be pulled to high.
> >
> > Fixes: d8f97da1b92d2 ("Bluetooth: hci_qca: Add support for QTI
> > Bluetooth chip wcn6750")
> > Reviewed-by: Miao-chen Chou <mcchou@chromium.org>
> > Signed-off-by: Sai Teja Aluvala <quic_saluvala@quicinc.com>
> > Signed-off-by: Balakrishna Godavarthi <quic_bgodavar@quicinc.com>
> > ---
> > drivers/bluetooth/hci_qca.c | 30 ++++++++++++++++++++++++------
> > 1 file changed, 24 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> > index eab34e2..c3862d1 100644
> > --- a/drivers/bluetooth/hci_qca.c
> > +++ b/drivers/bluetooth/hci_qca.c
> > @@ -219,6 +219,7 @@ struct qca_serdev {
> >       struct hci_uart  serdev_hu;
> >       struct gpio_desc *bt_en;
> >       struct gpio_desc *sw_ctrl;
> > +     struct gpio_desc *wlan_en;
> >       struct clk       *susclk;
> >       enum qca_btsoc_type btsoc_type;
> >       struct qca_power *bt_power;
>
> I am really against these intermixing of Bluetooth and WiFi details. Ther=
e is work ongoing to do some sequence power procedure. Maybe that is someth=
ing you should look into. This is a mess.
>
> And again, we are still hacking around hci_qca.c instead of writing a cle=
an serdev only driver for this hardware. I have the feeling that nobody lis=
tens to review comments these days. It is just hacking patches together to =
get hardware enabled somehow and then disappear.
>
> [Bala]: We are working on serdev like driver for our QCA platform.  We ar=
e in initial stages of discussion, and soon we will start the driver develo=
pment work.
> In mean to stop stability or functional issues we are trying to add these=
 HACKs in QCA driver.
>
> Regards
>
> Marcel
>