Re: [PATCH 1/2] spi: rockchip: add support for "cs-gpios" dts property

[jeffy]

Hi Geert,

On 06/12/2017 04:18 PM, Geert Uytterhoeven wrote:
> On Mon, Jun 12, 2017 at 9:15 AM, Shawn Lin <shawn.lin@xxxxxxxxxxxxxx> wrote:
> > On 2017/6/12 14:14, Jeffy Chen wrote:
> > > Support using "cs-gpios" property to specify cs gpios.
> > >
> > > Signed-off-by: Jeffy Chen <jeffy.chen@xxxxxxxxxxxxxx>
>
> > > index 83da493..02171b2 100644
> > > --- a/Documentation/devicetree/bindings/spi/spi-rockchip.txt
> > > +++ b/Documentation/devicetree/bindings/spi/spi-rockchip.txt
> > > @@ -17,6 +17,7 @@ Required Properties:
> > >           region.
> > >    - interrupts: The interrupt number to the cpu. The interrupt specifier
> > > format
> > >                  depends on the interrupt controller.
> > > +- cs-gpios : Specifies the gpio pins to be used for chipselects.
> >
> > It's not a required property, otherwise how other boards work as your
> > patch 2 only add this for rk3399-gru.
>
> > > --- a/drivers/spi/spi-rockchip.c
> > > +++ b/drivers/spi/spi-rockchip.c
>
> > > @@ -297,6 +302,50 @@ static void rockchip_spi_set_cs(struct spi_device
> > > *spi, bool enable)
> > >          pm_runtime_put_sync(rs->dev);
> > >    }
> > >    +static int rockchip_spi_setup(struct spi_device *spi)
> > > +{
> > > +       int ret = 0;
> > > +       unsigned long flags = (spi->mode & SPI_CS_HIGH) ?
> > > +                             GPIOF_OUT_INIT_LOW : GPIOF_OUT_INIT_HIGH;
> > > +       struct rockchip_spi_data *data = spi_get_ctldata(spi);
> > > +
> > > +       if (!gpio_is_valid(spi->cs_gpio))
> > > +               return 0;
>
> > return -EINVAL?
>
> Isn't this check meant to fall back to hardware CS if no cs-gpios property
> is present?

Thanks for your comment, and yes it is. I'll add a comment in the code 
to explain it :)
> Gr{oetje,eeting}s,
>
>                          Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                  -- Linus Torvalds