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Date:   Thu, 13 Oct 2022 19:11:12 +0000
From:   "mka@chromium.org" <mka@chromium.org>
To:     "Balakrishna Godavarthi (QUIC)" <quic_bgodavar@quicinc.com>
Cc:     Miao-chen Chou <mcchou@chromium.org>,
        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>,
        "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>,
        "Rocky Liao (QUIC)" <quic_rjliao@quicinc.com>,
        Alain Michaud <alainmichaud@google.com>,
        Abhishek Pandit-Subedi <abhishekpandit@chromium.org>,
        Zhengping Jiang <jiangzp@google.com>
Subject: Re: [PATCH v1 3/3] Bluetooth: hci_qca: WAR to handle WCN6750 HW issue
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On Wed, Jun 22, 2022 at 07:27:21AM +0000, Balakrishna Godavarthi (QUIC) wrote:
> Hi Marcel/Miao,
> 
> We are working on new driver, by 7/29 we will submit initial patch for review.

Has this ever been sent? I skimmed through the list archives and couldn't find it.

> -----Original Message-----
> From: Miao-chen Chou <mcchou@chromium.org> 
> Sent: Tuesday, May 10, 2022 8:47 AM
> To: Balakrishna Godavarthi (QUIC) <quic_bgodavar@quicinc.com>
> Cc: Marcel Holtmann <marcel@holtmann.org>; Andy Gross <agross@kernel.org>; robh+dt@kernel.org; bjorn.andersson@linaro.org; linux-arm-msm@vger.kernel.org; devicetree@vger.kernel.org; linux-kernel@vger.kernel.org; Johan Hedberg <johan.hedberg@gmail.com>; mka@chromium.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>
> Subject: Re: [PATCH v1 3/3] Bluetooth: hci_qca: WAR to handle WCN6750 HW issue
> 
> 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@linaro.org; linux-arm-msm@vger.kernel.org; 
> > devicetree@vger.kernel.org; linux-kernel@vger.kernel.org; Johan 
> > Hedberg <johan.hedberg@gmail.com>; mka@chromium.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. There is work ongoing to do some sequence power procedure. Maybe that is something you should look into. This is a mess.
> >
> > And again, we are still hacking around hci_qca.c instead of writing a clean serdev only driver for this hardware. I have the feeling that nobody listens 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 are in initial stages of discussion, and soon we will start the driver development work.
> > In mean to stop stability or functional issues we are trying to add these HACKs in QCA driver.
> >
> > Regards
> >
> > Marcel
> >