RE: [PATCH v1 3/3] Bluetooth: hci_qca: WAR to handle WCN6750 HW issue

[Balakrishna Godavarthi (QUIC)]

Hi Marcel/Miao,

We are working on new driver, by 7/29 we will submit initial patch for review.

Regards
Bala
-----Original Message-----
From: Miao-chen Chou <mcchou@xxxxxxxxxxxx> 
Sent: Tuesday, May 10, 2022 8:47 AM
To: Balakrishna Godavarthi (QUIC) <quic_bgodavar@xxxxxxxxxxx>
Cc: Marcel Holtmann <marcel@xxxxxxxxxxxx>; Andy Gross <agross@xxxxxxxxxx>; robh+dt@xxxxxxxxxx; bjorn.andersson@xxxxxxxxxx; linux-arm-msm@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Johan Hedberg <johan.hedberg@xxxxxxxxx>; mka@xxxxxxxxxxxx; linux-bluetooth@xxxxxxxxxxxxxxx; Hemant Gupta (QUIC) <quic_hemantg@xxxxxxxxxxx>; Sai Teja Aluvala (Temp) (QUIC) <quic_saluvala@xxxxxxxxxxx>; quic_rjliao <quic_rjliao@xxxxxxxxxxx>; Alain Michaud <alainmichaud@xxxxxxxxxx>; Abhishek Pandit-Subedi <abhishekpandit@xxxxxxxxxxxx>
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@xxxxxxxxxxx> wrote:
>
> Hi Marcel,
>
> -----Original Message-----
> From: Marcel Holtmann <marcel@xxxxxxxxxxxx>
> Sent: Friday, April 29, 2022 8:24 PM
> To: Balakrishna Godavarthi (QUIC) <quic_bgodavar@xxxxxxxxxxx>
> Cc: Andy Gross <agross@xxxxxxxxxx>; robh+dt@xxxxxxxxxx; 
> bjorn.andersson@xxxxxxxxxx; linux-arm-msm@xxxxxxxxxxxxxxx; 
> devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Johan 
> Hedberg <johan.hedberg@xxxxxxxxx>; mka@xxxxxxxxxxxx; 
> linux-bluetooth@xxxxxxxxxxxxxxx; Hemant Gupta (QUIC) 
> <quic_hemantg@xxxxxxxxxxx>; Sai Teja Aluvala (Temp) (QUIC) 
> <quic_saluvala@xxxxxxxxxxx>; quic_rjliao <quic_rjliao@xxxxxxxxxxx>; 
> mcchou@xxxxxxxxxxxx
> 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@xxxxxxxxxxxx>
> > Signed-off-by: Sai Teja Aluvala <quic_saluvala@xxxxxxxxxxx>
> > Signed-off-by: Balakrishna Godavarthi <quic_bgodavar@xxxxxxxxxxx>
> > ---
> > 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
>