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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Thu, 20 Jan 2022 11:51:30 +0200
Message-ID: <CAHp75VcCpye1u3+PK=C3CT8fMHPSOsXTL5AhbLVy0YyGWfyfkQ@mail.gmail.com>
Subject: Re: [PATCH v6 1/2] spi: Add spi driver for Sunplus SP7021
To:     =?UTF-8?B?TGggS3VvIOmDreWKm+ixqg==?= <lh.Kuo@sunplus.com>
Cc:     Li-hao Kuo <lhjeff911@gmail.com>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Mark Brown <broonie@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        linux-spi <linux-spi@vger.kernel.org>,
        devicetree <devicetree@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        =?UTF-8?B?V2VsbHMgTHUg5ZGC6Iqz6aiw?= <wells.lu@sunplus.com>
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On Thu, Jan 20, 2022 at 11:22 AM Lh Kuo =E9=83=AD=E5=8A=9B=E8=B1=AA <lh.Kuo=
@sunplus.com> wrote:

...

> > > +       if (xfer->tx_buf)
> > > +               dma_unmap_single(dev, xfer->tx_dma, xfer->len, DMA_TO=
_DEVICE);
> > > +       if (xfer->rx_buf)
> > > +               dma_unmap_single(dev, xfer->rx_dma, xfer->len,
> > > + DMA_FROM_DEVICE);
> >
> > Why can't you use SPI core DMA mapping code?
>
> I didn't find the SPI core DMA mapping code for single maping.
> The method currently used is the general DMA single-map code usage method=
.

Why do you need single page mapping?
What's wrong with SG mapping that SPI core provides?

...

> > > +       device_set_node(&ctlr->dev, pdev->dev.fwnode);
> >
> > Use dev_fwnode() in the second argument.
>
> You mean as below ?
>
> device_set_node(&ctlr->dev, dev_fwnode(dev));

Yes.

--=20
With Best Regards,
Andy Shevchenko