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Message-ID: <50814A5A.8070206@ti.com>
Date: Fri, 19 Oct 2012 14:40:58 +0200
From: Benoit Cousson <b-cousson@ti.com>
Organization: Texas Instruments
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To: Matt Porter <mporter@ti.com>
CC: "Philip, Avinash" <avinashphilip@ti.com>, <linux@arm.linux.org.uk>,
        <tony@atomide.com>, <linux-arm-kernel@lists.infradead.org>,
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        <nsekhar@ti.com>, <gururaja.hebbar@ti.com>
Subject: Re: [PATCH v2] arm/dts: AM33XX: Add SPI device tree data
References: <1347946228-25874-1-git-send-email-avinashphilip@ti.com> <50810E2F.5@ti.com> <20121019113016.GE25164@beef>
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Hi Matt,

On 10/19/2012 01:30 PM, Matt Porter wrote:
> On Fri, Oct 19, 2012 at 10:24:15AM +0200, Benoit Cousson wrote:
>> Hi Avinash,
>>
>> This look good to me except the: status = "disabled".
>>
>> The "disabled" should be reserved for variant that does not contain the IP.
>> Is it the case here?
> 
> http://comments.gmane.org/gmane.linux.drivers.devicetree/18968 is what
> I've been going by with the DTS support in the EDMA dmaengine series. It
> does make the most sense to only enable what you need in the
> <board>.dts.

Thanks, I missed that thread. That being said, there is no real rational
:-)
It seems to be a preference more than anything else.
I'm curious now, why powerpc was not really using that approach?

I'd rather explicitly disable an IP than assuming than it is disabled by
default and then enabling it in the board file. But again it is just a
different view point, since at the end it will have the same effect.

If we really want the disabled state to be the default state, why is it
not disabled in the DT fmwk by default?

Regards,
Benoit

> 
> -Matt
> 
>> On 09/18/2012 07:30 AM, Philip, Avinash wrote:
>>> Add McSPI data node to AM33XX device tree file. The McSPI module (and so
>>> as the driver) is reused from OMAP4.
>>>
>>> Signed-off-by: Philip, Avinash <avinashphilip@ti.com>
>>> Tested-by: Matt Porter <mporter@ti.com>
>>> ---
>>> Changes since v1:
>>>         - Corrected reg offset in reg DT entry.
>>>
>>> :100644 100644 ff3badb... 065fd54... M	arch/arm/boot/dts/am33xx.dtsi
>>>  arch/arm/boot/dts/am33xx.dtsi |   25 +++++++++++++++++++++++++
>>>  1 files changed, 25 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/arch/arm/boot/dts/am33xx.dtsi b/arch/arm/boot/dts/am33xx.dtsi
>>> index ff3badb..065fd54 100644
>>> --- a/arch/arm/boot/dts/am33xx.dtsi
>>> +++ b/arch/arm/boot/dts/am33xx.dtsi
>>> @@ -219,5 +219,30 @@
>>>  			interrupt-parent = <&intc>;
>>>  			interrupts = <91>;
>>>  		};
>>> +
>>> +		spi0: spi@48030000 {
>>> +			compatible = "ti,omap4-mcspi";
>>> +			#address-cells = <1>;
>>> +			#size-cells = <0>;
>>> +			reg = <0x48030000 0x400>;
>>> +			interrupt-parent = <&intc>;
>>> +			interrupt = <65>;
>>> +			ti,spi-num-cs = <2>;
>>> +			ti,hwmods = "spi0";
>>> +			status = "disabled";
>>> +
>>> +		};
>>> +
>>> +		spi1: spi@481a0000 {
>>> +			compatible = "ti,omap4-mcspi";
>>> +			#address-cells = <1>;
>>> +			#size-cells = <0>;
>>> +			reg = <0x481a0000 0x400>;
>>> +			interrupt-parent = <&intc>;
>>> +			interrupt = <125>;
>>> +			ti,spi-num-cs = <2>;
>>> +			ti,hwmods = "spi1";
>>> +			status = "disabled";
>>> +		};
>>>  	};
>>>  };
>>>
>>
>> --
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