RE: [PATCH v2 2/2] spi: add SPI controller driver for UniPhier SoC

[Keiji Hayashibara]

Hello Andy,

> -----Original Message-----
> From: linux-kernel-owner@xxxxxxxxxxxxxxx [mailto:linux-kernel-owner@xxxxxxxxxxxxxxx] On Behalf Of Andy
> Shevchenko
> Sent: Thursday, July 26, 2018 10:44 PM
> To: Hayashibara, Keiji/æå åä <hayashibara.keiji@xxxxxxxxxxxxx>
> Cc: Mark Brown <broonie@xxxxxxxxxx>; Rob Herring <robh+dt@xxxxxxxxxx>; Mark Rutland <mark.rutland@xxxxxxx>;
> Yamada, Masahiro/åç çå <yamada.masahiro@xxxxxxxxxxxxx>; linux-spi <linux-spi@xxxxxxxxxxxxxxx>; linux-arm
> Mailing List <linux-arm-kernel@xxxxxxxxxxxxxxxxxxx>; devicetree <devicetree@xxxxxxxxxxxxxxx>; Masami Hiramatsu
> <masami.hiramatsu@xxxxxxxxxx>; Jassi Brar <jaswinder.singh@xxxxxxxxxx>; Linux Kernel Mailing List
> <linux-kernel@xxxxxxxxxxxxxxx>; Hayashi, Kunihiko/æ éå <hayashi.kunihiko@xxxxxxxxxxxxx>
> Subject: Re: [PATCH v2 2/2] spi: add SPI controller driver for UniPhier SoC
> 
> On Thu, Jul 26, 2018 at 12:38 PM, Keiji Hayashibara <hayashibara.keiji@xxxxxxxxxxxxx> wrote:
> 
> >> > +       /* check if requested speed is too small */
> >> > +       if (ckrat > SSI_MAX_CLK_DIVIDER)
> >>
> >> > +               return -EINVAL;
> >>
> >> So, does this critical?
> >
> > If set the value to SSI_MAX_CLK_DIVIDER, the clock frequency will be set high.
> > I don't change it to high frequency, and it is daringly an error.
> > On the other hand, when changing to low frequency, I will change it automatically.
> 
> No. My point is, if somehow user asks for that condition to be happened you bail out, while when using clamp_val()
> you may continue to work at maximum limit, though issue warning to user, for example.

Thank you. I understood what you pointed out. 
However, I found this code unnecessary as pointed out by Radu, 
so I will delete it.

> >> > +
> >> > +       if (ckrat < SSI_MIN_CLK_DIVIDER)
> >> > +               ckrat = SSI_MIN_CLK_DIVIDER;
> >>
> >> clamp_val()  / max() ?
> >
> > I will modify it to use max().
> 
> See above.

This is also the same as above.

> --
> With Best Regards,
> Andy Shevchenko

-----------------
Best Regards,
Keiji Hayashibara