Re: [PATCH 11/11] dt: Exynos: add Snow SPI NOR node.

Marek Vasut
2015-06-04T15:30:05Z

On Thursday, June 04, 2015 at 04:04:18 AM, Krzysztof Kozlowski wrote:
> On 04.06.2015 06:26, Michal Suchanek wrote:
> > The Snow has onboard SPI NOR flash which contains the bootloader.
> >
> > Add DT node for this flash chip. The flash is rated 133MHz but the pl330
> > controller can transfer only up to 128 bytes at this speed so use more
> > conservative settings. Even at 40MHz pl330 can transfer at most 64k with
> > the current driver.
> >
> > Signed-off-by: Michal Suchanek <hramrach@gmail.com>
> > ---
> >
> > arch/arm/boot/dts/exynos5250-snow.dts | 12 ++++++++++++
> > 1 file changed, 12 insertions(+)
> >
> > diff --git a/arch/arm/boot/dts/exynos5250-snow.dts
> > b/arch/arm/boot/dts/exynos5250-snow.dts index 1fa72cf..38e4cda 100644
> > --- a/arch/arm/boot/dts/exynos5250-snow.dts
> > +++ b/arch/arm/boot/dts/exynos5250-snow.dts
> > @@ -691,6 +691,18 @@
> >
> > num-cs = <1>;
> > cs-gpios = <&gpa2 5 0>;
> > status = "okay";
> >
> > + flash: m25p80@0 {
>
> The indentation looks odd. This should be at the same level as "status".
>
> > + #address-cells = <1>;
> > + #size-cells = <1>;
> > + compatible = "jedec,spi-nor";
> > + reg = <0>;
> > + spi-max-frequency = <40000000>;
>
> So actually you wanted 133 MHz but as a workaround for DMA issue you use
> 40 MHz, right? Could you add here a small TODO note in comment about it?

I disagree. There is a problem, the problem should actually be analyzed and
fixed, not just postponed with some TODO nonsense.

Best regards,
Marek Vasut