Re: [PATCH V5] dmaengine: Loongson1: Add Loongson1 dmaengine driver

From: Kelvin Cheung <keguang.zhang@gmail.com>
To: Vinod Koul <vkoul@kernel.org>
Cc: Greg KH <gregkh@linuxfoundation.org>,
	dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH V5] dmaengine: Loongson1: Add Loongson1 dmaengine driver
Date: Wed, 21 Jul 2021 20:22:10 +0800	[thread overview]
Message-ID: <CAJhJPsV211=Y_wrXqaiWz7Tqhvbj-ETwSNWqLcbt8PHi8=JMLA@mail.gmail.com> (raw)
In-Reply-To: <YPa/DsO1vWcXKJKd@matsya>

Hi Vinod, Greg,

Vinod Koul <vkoul@kernel.org> 于2021年7月20日周二 下午8:18写道：
>
> On 20-07-21, 13:48, Greg KH wrote:
> > On Tue, Jul 20, 2021 at 05:13:53PM +0530, Vinod Koul wrote:
> > > On 17-07-21, 19:39, Greg KH wrote:
> > > > On Sat, Jul 17, 2021 at 08:09:45PM +0530, Vinod Koul wrote:
> > > > > On 17-07-21, 18:57, Kelvin Cheung wrote:
> > > > > > Vinod Koul <vkoul@kernel.org> 于2021年7月14日周三 下午1:14写道：
> > > > > > >
> > > > > > > On 04-07-21, 23:33, Keguang Zhang wrote:
> > > > > > >
> > > > > > > > +static struct platform_driver ls1x_dma_driver = {
> > > > > > > > +     .probe  = ls1x_dma_probe,
> > > > > > > > +     .remove = ls1x_dma_remove,
> > > > > > > > +     .driver = {
> > > > > > > > +             .name   = "ls1x-dma",
> > > > > > > > +     },
> > > > > > > > +};
> > > > > > > > +
> > > > > > > > +module_platform_driver(ls1x_dma_driver);
> > > > > > >
> > > > > > > so my comment was left unanswered, who creates this device!
> > > > > >
> > > > > > Sorry!
> > > > > > This patch will create the device: https://patchwork.kernel.org/patch/12281691
> > > > >
> > > > > Greg, looks like the above patch creates platform devices in mips, is
> > > > > that the right way..?
> > > >
> > > > I do not understand, what exactly is the question?
> > >
> > > So this patch was adding Loongson1 dmaengine driver which is a platform
> > > device. I asked about the platform device and was told that [1] creates
> > > the platform device. I am not sure if that is the recommended way given
> > > that you have been asking people to not use platform devices.
> >
> > Yes, but this link:
> >
> > > [1]: https://patchwork.kernel.org/patch/12281691
> >
> > Does look like a "real" platform device in that you have fixed resources
> > for the device and no way to discover it on your own.
> >
> > But why are you not using DT for this?  That looks like the old platform
> > data files.
>
> Apparently I was told that this platform does not use DT :( Looking at
> it it should.. Maybe Kelvin can explain why..

Yes, the DT support of Loongson32 is still on the way.
Therefore, I have to use the old way to let the driver work.
I will update this driver once this platform supports DT.

>
> --
> ~Vinod

-- 
Best regards,

Kelvin Cheung