From:   Neeraj sanjay kale <neeraj.sanjaykale@nxp.com>
To:     Greg KH <gregkh@linuxfoundation.org>
CC:     "davem@davemloft.net" <davem@davemloft.net>,
        "edumazet@google.com" <edumazet@google.com>,
        "kuba@kernel.org" <kuba@kernel.org>,
        "pabeni@redhat.com" <pabeni@redhat.com>,
        "robh+dt@kernel.org" <robh+dt@kernel.org>,
        "krzysztof.kozlowski+dt@linaro.org" 
        <krzysztof.kozlowski+dt@linaro.org>,
        "marcel@holtmann.org" <marcel@holtmann.org>,
        "johan.hedberg@gmail.com" <johan.hedberg@gmail.com>,
        "luiz.dentz@gmail.com" <luiz.dentz@gmail.com>,
        "jirislaby@kernel.org" <jirislaby@kernel.org>,
        "alok.a.tiwari@oracle.com" <alok.a.tiwari@oracle.com>,
        "hdanton@sina.com" <hdanton@sina.com>,
        "ilpo.jarvinen@linux.intel.com" <ilpo.jarvinen@linux.intel.com>,
        "leon@kernel.org" <leon@kernel.org>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-bluetooth@vger.kernel.org" <linux-bluetooth@vger.kernel.org>,
        "linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>,
        Amitkumar Karwar <amitkumar.karwar@nxp.com>,
        Rohit Fule <rohit.fule@nxp.com>,
        Sherry Sun <sherry.sun@nxp.com>
Subject: Re: [PATCH v5] Bluetooth: NXP: Add protocol support for NXP Bluetooth
 chipsets
Thread-Topic: [PATCH v5] Bluetooth: NXP: Add protocol support for NXP
 Bluetooth chipsets
Thread-Index: AQHZR4/1Uya9NEuwq0+Oa9nMQHXKXA==
Date:   Thu, 23 Feb 2023 14:06:01 +0000
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Hi Greg,

Thank you again for the feedback.
I will work on this and submit a new patch again.

Thanks,
Neeraj

>=20
> On Thu, Feb 23, 2023 at 01:57:58PM +0000, Neeraj sanjay kale wrote:
> > Hi Greg,
> >
> > Thank you for your feedback.
> >
> > >
> > > > +
> > > > +static int init_baudrate =3D 115200;
> > >
> > > and neither will this, as you need to support multiple devices in
> > > the system, your driver should never be only able to work with one
> device.
> > > Please make these device-specific things, not the same for the whole
> driver.
> > >
> >
> > I am using this init_baudrate as a module parameter static int
> > init_baudrate =3D 115200; module_param(init_baudrate, int, 0444);
> > MODULE_PARM_DESC(init_baudrate, "host baudrate after FW download:
> > default=3D115200");
>=20
> Ah, totally missed that.
>=20
> That is not ok, sorry, this is not the 1990's, we do not use module param=
eters
> for drivers as that obviously does not work at all for when you have mult=
iple
> devices controlled by that driver.  Please make this all dynamic and "jus=
t
> work" properly for all devices.
>=20
> > We need this parameter configurable since different chip module vendors
> using the same NXP chipset, configure these chips differently.
>=20
> Then you are pushing the configuration to userspace for someone else to p=
ut
> on their boot command line?  that's crazy, please never do that.
>=20
> > For example, module vendor A distributes his modules based on NXP
> 88w8987 chips with a different configuration compared to module vendor B
> (based on NXP 88w8987), and the init_baudrate is one of the important
> distinctions between them.
>=20
> Then put that logic in DT where it belongs.
>=20
> > If we are able to keep this init_baudrate configurable, while compiling
> btnxpuart.ko as module, we will be able to support such baudrate variatio=
ns.
>=20
> Again, no, that's not how tty or serial devices work.
>=20
> thanks,
>=20
> greg k-h