RE: [PATCH 4/4] arm64: dts: lx2160a: update fspi node

[Yogesh Narayan Gaur]

Hi Boris,

> -----Original Message-----
> From: Boris Brezillon [mailto:boris.brezillon@xxxxxxxxxxx]
> Sent: Thursday, October 4, 2018 2:48 PM
> To: Yogesh Narayan Gaur <yogeshnarayan.gaur@xxxxxxx>
> Cc: linux-mtd@xxxxxxxxxxxxxxxxxxx; marek.vasut@xxxxxxxxx; vigneshr@xxxxxx;
> linux-spi@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; robh@xxxxxxxxxx;
> mark.rutland@xxxxxxx; shawnguo@xxxxxxxxxx; linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx; computersforpeace@xxxxxxxxx;
> frieder.schrempf@xxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH 4/4] arm64: dts: lx2160a: update fspi node
> 
> On Thu,  4 Oct 2018 14:18:40 +0530
> Yogesh Gaur <yogeshnarayan.gaur@xxxxxxx> wrote:
> 
> > Flash mt35xu512aba connected to FlexSPI controller supports
> > 1-1-8 protocol.
> > Added flag spi-rx-bus-width and spi-tx-bus-width with values as
> > 8 and 1 respectively for both flashes connected at CS0 and CS1.
> >
> > Signed-off-by: Yogesh Gaur <yogeshnarayan.gaur@xxxxxxx>
> > ---
> >  arch/arm64/boot/dts/freescale/fsl-lx2160a-rdb.dts | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/arch/arm64/boot/dts/freescale/fsl-lx2160a-rdb.dts
> > b/arch/arm64/boot/dts/freescale/fsl-lx2160a-rdb.dts
> > index 901ca346..817175a 100644
> > --- a/arch/arm64/boot/dts/freescale/fsl-lx2160a-rdb.dts
> > +++ b/arch/arm64/boot/dts/freescale/fsl-lx2160a-rdb.dts
> > @@ -42,6 +42,8 @@
> >  		m25p,fast-read;
> >  		spi-max-frequency = <20000000>;
> >  		reg = <0>;
> > +		spi-rx-bus-width = <8>;
> > +		spi-tx-bus-width = <1>;
> 
> Why 1? The flash is already flagged with SPI_NOR_OCTAL_READ, which means
> only the read path will use 1-1-8 mode, so you can safely set spi-tx-bus-width
> here and let the framework choose the appropriate mode based on the flash
> capabilities.

Ok.

> 
> >  	};
> >
> >  	mt35xu512aba1: flash@1 {
> > @@ -51,6 +53,8 @@
> >  		m25p,fast-read;
> >  		spi-max-frequency = <20000000>;
> >  		reg = <1>;
> > +		spi-rx-bus-width = <8>;
> > +		spi-tx-bus-width = <1>;
> >  	};
> >  };
> >