Re: [PATCH V2] clk: mxs: Fix invalid 32-bit access to frac registers

Mike Turquette
2015-01-28T01:51:49Z

Quoting Marek Vasut (2015-01-21 15:39:01)
> On Wednesday, January 21, 2015 at 05:16:03 PM, Zhi Li wrote:
> > On Sun, Dec 28, 2014 at 4:26 AM, Stefan Wahren <stefan.wahren@i2se.com> wrote:
> > > According to i.MX23 and i.MX28 reference manual the fractional
> > > clock control registers must be addressed by byte instructions.
> >
> > I don't think mx23 and mx28 have such limitation. I will double check
> > with IC team about this.
> > RTL is generated from a xml file. All registers implement is unified.
> > I don't think only clock control register have such limitation and
> > other registers not.
>
> Hi,
>
> Section 10.8.24 in the MX28 datasheet (Fractional Clock Control Register 0)
> states otherwise, but maybe the documentation is simply not matching the
> silicon.
>
> Here's a quote:
> "
> This register controls the 9-phase fractional clock dividers. The fractional
> clock frequencies are a product of the values in these registers. NOTE: This
> register can only be addressed by byte instructions. Addressing word or half-
> word are not allowed.
> "
>
> I also recall seeing weird behavior when these registers were accessed by word
> access in U-Boot, so I believe the datasheet is correct.

Hi Frank,

Are you satisfied with this patch?

Regards,
Mike

>
> Best regards,
> Marek Vasut