Patchwork [1/3] ARM: dts: mxs: set dcp to "disabled" by default

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Submitter Lothar Waßmann
Date Aug. 8, 2013, 1:30 p.m.
Message ID <1375968629-10091-2-git-send-email-LW@KARO-electronics.de>
Download mbox | patch
Permalink /patch/265729/
State New
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Comments

Lothar Waßmann - Aug. 8, 2013, 1:30 p.m.
Reintroduce 'status = "disabled"' for the dcp node that was dropped by
commit 519d8b1a "Added support for Freescale's DCP co-processor".

Explicitly enable it in imx28-evk which is referenced in the commit
message of that commit.

Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
---
 arch/arm/boot/dts/imx28-evk.dts |    4 ++++
 arch/arm/boot/dts/imx28.dtsi    |    3 ++-
 2 files changed, 6 insertions(+), 1 deletions(-)
Shawn Guo - Aug. 12, 2013, 11:05 a.m.
On Thu, Aug 08, 2013 at 03:30:27PM +0200, Lothar Waßmann wrote:
> Reintroduce 'status = "disabled"' for the dcp node that was dropped by
> commit 519d8b1a "Added support for Freescale's DCP co-processor".

For IP blocks that do not have pins to be routed on boards, it should be
fine to have it enabled in <soc>.dtsi.

Shawn

> 
> Explicitly enable it in imx28-evk which is referenced in the commit
> message of that commit.
> 
> Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
> ---
>  arch/arm/boot/dts/imx28-evk.dts |    4 ++++
>  arch/arm/boot/dts/imx28.dtsi    |    3 ++-
>  2 files changed, 6 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/arm/boot/dts/imx28-evk.dts b/arch/arm/boot/dts/imx28-evk.dts
> index dff2279..ac790bb 100644
> --- a/arch/arm/boot/dts/imx28-evk.dts
> +++ b/arch/arm/boot/dts/imx28-evk.dts
> @@ -361,3 +361,7 @@
>  		default-brightness-level = <6>;
>  	};
>  };
> +
> +&dcp {
> +	status = "okay";
> +};
> diff --git a/arch/arm/boot/dts/imx28.dtsi b/arch/arm/boot/dts/imx28.dtsi
> index e459d63..ea99d09 100644
> --- a/arch/arm/boot/dts/imx28.dtsi
> +++ b/arch/arm/boot/dts/imx28.dtsi
> @@ -794,9 +794,10 @@
>  			};
>  
>  			dcp: dcp@80028000 {
> +				compatible = "fsl-dcp";
>  				reg = <0x80028000 0x2000>;
>  				interrupts = <52 53 54>;
> -				compatible = "fsl-dcp";
> +				status = "disabled";
>  			};
>  
>  			pxp: pxp@8002a000 {
> -- 
> 1.7.2.5
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Lothar Waßmann - Aug. 12, 2013, 12:05 p.m.
Hi,

Shawn Guo writes:
> On Thu, Aug 08, 2013 at 03:30:27PM +0200, Lothar Waßmann wrote:
> > Reintroduce 'status = "disabled"' for the dcp node that was dropped by
> > commit 519d8b1a "Added support for Freescale's DCP co-processor".
> 
> For IP blocks that do not have pins to be routed on boards, it should be
> fine to have it enabled in <soc>.dtsi.
> 
That means that when a new driver is added, it will start wasting
resources on all board using that SoC unless the board maintainers
explicitly disable that driver in DTB.

I would prefer things to be the other way:
New drivers (no matter whether for chip-internal or external hardware)
should require to be explicitly enabled for those platforms on which
they are being used.


Lothar Waßmann
Kumar Gala - Aug. 12, 2013, 2:17 p.m.
On Aug 12, 2013, at 7:05 AM, Lothar Waßmann wrote:

> Hi,
> 
> Shawn Guo writes:
>> On Thu, Aug 08, 2013 at 03:30:27PM +0200, Lothar Waßmann wrote:
>>> Reintroduce 'status = "disabled"' for the dcp node that was dropped by
>>> commit 519d8b1a "Added support for Freescale's DCP co-processor".
>> 
>> For IP blocks that do not have pins to be routed on boards, it should be
>> fine to have it enabled in <soc>.dtsi.
>> 
> That means that when a new driver is added, it will start wasting
> resources on all board using that SoC unless the board maintainers
> explicitly disable that driver in DTB.
> 
> I would prefer things to be the other way:
> New drivers (no matter whether for chip-internal or external hardware)
> should require to be explicitly enabled for those platforms on which
> they are being used.

But that enablement should be in the kernel and not the device tree.  The device tree is describing the HW, if the DCP exists and is usable w/o an external IO than by default it should be enabled in the SoC .dts

- k

--
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

Patch

diff --git a/arch/arm/boot/dts/imx28-evk.dts b/arch/arm/boot/dts/imx28-evk.dts
index dff2279..ac790bb 100644
--- a/arch/arm/boot/dts/imx28-evk.dts
+++ b/arch/arm/boot/dts/imx28-evk.dts
@@ -361,3 +361,7 @@ 
 		default-brightness-level = <6>;
 	};
 };
+
+&dcp {
+	status = "okay";
+};
diff --git a/arch/arm/boot/dts/imx28.dtsi b/arch/arm/boot/dts/imx28.dtsi
index e459d63..ea99d09 100644
--- a/arch/arm/boot/dts/imx28.dtsi
+++ b/arch/arm/boot/dts/imx28.dtsi
@@ -794,9 +794,10 @@ 
 			};
 
 			dcp: dcp@80028000 {
+				compatible = "fsl-dcp";
 				reg = <0x80028000 0x2000>;
 				interrupts = <52 53 54>;
-				compatible = "fsl-dcp";
+				status = "disabled";
 			};
 
 			pxp: pxp@8002a000 {