Re: [PATCH] ARM: dts: da850-evm: add clock properties to the nand node

[David Lechner]

On 02/06/2018 12:16 PM, David Lechner wrote:
> On 02/06/2018 07:51 AM, Sekhar Nori wrote:
> > On Tuesday 06 February 2018 06:38 PM, Bartosz Golaszewski wrote:
> > > 2018-02-06 12:07 GMT+01:00 Sekhar Nori <nsekhar@xxxxxx>:
> > > > On Monday 05 February 2018 09:22 PM, Bartosz Golaszewski wrote:
> > > > > From: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
> > > > >
> > > > > Make nand work with the common clock framework by specifying which
> > > > > clock should be used and what name to look up.
> > > > >
> > > > > Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
> > > > > ---
> > > > > Â arch/arm/boot/dts/da850-evm.dts | 3 +++
> > > > > Â 1 file changed, 3 insertions(+)
> > > > >
> > > > > diff --git a/arch/arm/boot/dts/da850-evm.dts b/arch/arm/boot/dts/da850-evm.dts
> > > > > index a86a8a1816f2..2602ad8e99ee 100644
> > > > > --- a/arch/arm/boot/dts/da850-evm.dts
> > > > > +++ b/arch/arm/boot/dts/da850-evm.dts
> > > > > @@ -296,6 +296,9 @@
> > > > > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ reg = <0 0x02000000 0x02000000
> > > > > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 1 0x00000000 0x00008000>;
> > > > >
> > > > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ clocks = <&psc0 3>;
> > > > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ clock-names = "aemif";
> > > >
> > > > Looks like this is being added only to satisfy the devm_clk_get() call
> > > > in nand_davinci_probe() which I think is superfluous since we also
> > > > enable the same clock in aemif_probe().
> > > >
> > > > Perhaps the better solution is to drip the clk code in
> > > > drivers/mtd/nand/davinci_nand.c and shift legacy code to start using
> > > > drivers/memory/aemif.c as well? This way we can also drop
> > > > arch/arm/mach-davinci/aemif.c
> > > >
> > > > Thanks,
> > > > Sekhar
> > >
> > > Yes, this sounds good, but I think we should leave it for later as an
> > > additional improvement, once everything else is in place. I think
> > > these patches should be applied together with David's series in order
> > > to not break the support on davinci boards and the aemif work would go
> > > in later as a follow-up. How about that?
> >
> > No, I dont think we should add temporary hacks to DT to work around
> > driver issues (I do think its a hack since the clock belongs to aemif
> > module not NAND flash).
> >
> > An easier driver hack might be to not treat devm_clk_get() failure in
> > davinci_nand.c as catastrophic. It will safely fail in DT case and we
> > should get the clock in legacy boot case.
> >
> > I think we are looking at a driver update dependency anyway.
>
> It looks like keystone.dtsi is using the clock-ranges property in the
> aemif node to pass the clock to child nodes. Could we not do the same
> in da850.dtsi?

Bartosz, please try this instead of your patch.

FYI, this is just following the existing memory-controllers/ti-aemif.txt
device tree bindings, so not a "hack".

---
diff --git a/arch/arm/boot/dts/da850.dtsi b/arch/arm/boot/dts/da850.dtsi
index 3a1f2ce..ff9d807 100644
--- a/arch/arm/boot/dts/da850.dtsi
+++ b/arch/arm/boot/dts/da850.dtsi
@@ -796,6 +796,8 @@
 		ranges = <0 0 0x60000000 0x08000000
 			  1 0 0x68000000 0x00008000>;
 		clocks = <&psc0 3>;
+		clock-names = "aemif";
+		clock-ranges;
 		status = "disabled";
 	};
 	memctrl: memory-controller@b0000000 {
---