Re: [PATCH 3/4 v3][RFC] arm64: renesas: Add initial r8a7795 SoC support

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Geert,

On Thursday 20 August 2015 09:43:34 Geert Uytterhoeven wrote:
> On Wed, Aug 19, 2015 at 11:29 PM, Laurent Pinchart wrote:
> >> > Also, while you're thinking about the perfect clock binding, please do
> >> > consider dropping clock-output-names if you can. Specifying clock-names
> >> > alongside the clocks property inside of the consumer node is a bit more
> >> > elegant in my opinion. This is also a bit easier if you think about
> >> > expressing your clock data with C inside of your provider driver.
> >> 
> >> Makes sense. I don't think anything relies on the "clock-output-names"
> >> ... currently.
> >> 
> >> I was going to use it for identifying the GIC clock, though:
> >> 
> >> --- a/drivers/clk/shmobile/clk-mstp.c
> >> +++ b/drivers/clk/shmobile/clk-mstp.c
> >> @@ -144,6 +144,9 @@ cpg_mstp_clock_register(const char *name, const char
> >> *paren init.name = name;
> >> 
> >>         init.ops = &cpg_mstp_clock_ops;
> >>         init.flags = CLK_IS_BASIC | CLK_SET_RATE_PARENT;
> >> 
> >> +       /* INTC-SYS is the module clock of the GIC, and must not be
> >> disabled */
> >> +       if (!strcmp(name, "intc-sys"))
> >> +               init.flags |= CLK_ENABLE_HAND_OFF;
> >> 
> >>         init.parent_names = &parent_name;
> >>         init.num_parents = 1;
> >> 
> >> (FTR, on R-Car Gen3 the clock is called "intc-ap", not "intc-sys",
> >> doh...).
> >> 
> >> This does put some reliance on (undocumented) naming in DT, though, so
> >> not
> >> having the "clock-output-names" would solve that.
> > 
> > Using the clock name is indeed very messy, let's avoid that.
> > 
> >> However, while "intc-sys"/"intc-ap" (if existent) is always MSTP408,
> >> MSTP408 is used for other modules on R-Car Gen1 and most older SoCs. so
> >> it would complicate the driver code.
> > 
> > How about setting the flag based on information provided in DT ?
> 
> Like scanning DT for the GIC, and looking for its clock?
> 
> I don't want to add an explicit flag in DT, as it's not a hardware property,
> but a deficiency of the current GIC driver/subsystem.

What are the changes we can fix the GIC driver in a reasonable time frame ?

-- 
Regards,

Laurent Pinchart