Re: [PATCH] spi: dw: Set default value if reg-io-width isn't specified

[Kunihiko Hayashi]

Hi Serge,

On 2023/08/08 7:57, Serge Semin wrote:
> On Mon, Aug 07, 2023 at 09:16:21AM +0900, Kunihiko Hayashi wrote:
> > According to the dt-bindings, the default value of reg-io-width is 4.
> > However, the value becomes zero when reg-io-width isn't specified.
>
> This semantic is implied by the dw_read_io_reg() and dw_write_io_reg()
> methods. It doesn't seem like that much necessary duplicating it in the
> property parse procedure, if not to say - redundant.

I see. Currently since the variable reg_io_width has no other references
other than dw_{read, write}_io_reg(), it means the default value is taken
if this is zero.

So, I think we should be careful when actually using the value of
this variable.

Thank you,

> -Serge(y)
>
> > Should set the actual value to dws->reg_io_width, considering it
> > referenced.
> >
> > Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@xxxxxxxxxxxxx>
> > ---
> >   drivers/spi/spi-dw-mmio.c | 4 +++-
> >   1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/spi/spi-dw-mmio.c b/drivers/spi/spi-dw-mmio.c
> > index a963bc96c223..7eafc07ef7aa 100644
> > --- a/drivers/spi/spi-dw-mmio.c
> > +++ b/drivers/spi/spi-dw-mmio.c
> > @@ -369,7 +369,9 @@ static int dw_spi_mmio_probe(struct platform_device
> *pdev)
> >   
> >   	dws->max_freq = clk_get_rate(dwsmmio->clk);
> >   
> > -	device_property_read_u32(&pdev->dev, "reg-io-width",
> &dws->reg_io_width);
> > +	if (device_property_read_u32(&pdev->dev, "reg-io-width",
> > +				     &dws->reg_io_width))
> > +		dws->reg_io_width = 4;
> >   
> >   	num_cs = 4;
> >   
> > --
> > 2.25.1

---
Best Regards
Kunihiko Hayashi