Re: [PATCH v5 01/16] dt-bindings: mtd: gpmc-onenand: Update properties description

From: Roger Quadros <rogerq@ti.com>
To: Ladislav Michl <ladis@linux-mips.org>,
	Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: Rob Herring <robh@kernel.org>,
	Aaro Koskinen <aaro.koskinen@iki.fi>,
	Tony Lindgren <tony@atomide.com>,
	Peter Ujfalusi <peter.ujfalusi@ti.com>,
	Kyungmin Park <kyungmin.park@samsung.com>,
	linux-mtd@lists.infradead.org, linux-omap@vger.kernel.org,
	devicetree@vger.kernel.org
Subject: Re: [PATCH v5 01/16] dt-bindings: mtd: gpmc-onenand: Update properties description
Date: Fri, 15 Dec 2017 12:18:59 +0200	[thread overview]
Message-ID: <23d7ad3c-e6cd-3ba6-269a-1788371d13c3@ti.com> (raw)
In-Reply-To: <20171130130907.GA16809@lenoch>

Ladislav,

On 30/11/17 15:09, Ladislav Michl wrote:
> On Thu, Nov 30, 2017 at 11:25:44AM +0100, Boris Brezillon wrote:
>> +Rob and the DT ML
>>
>> On Wed, 15 Nov 2017 17:24:58 +0100
>> Ladislav Michl <ladis@linux-mips.org> wrote:
>>
>>> Compatible property is required for OMAP2+ mtd driver. Also
>>> add INT pin gpio description and delete unused dma-channel
>>> property.
>>>
>>> Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
>>> Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
>>> Acked-by: Roger Quadros <rogerq@ti.com>
>>> ---
>>>
>>> Changes in v5:
>>> - renamed R/B pin to INT pin
>>>
>>> Changes in v4:
>>> - new patch
>>>
>>> Changes in v3: None
>>> Changes in v2: None
>>>
>>>  Documentation/devicetree/bindings/mtd/gpmc-onenand.txt | 6 ++++--
>>>  1 file changed, 4 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/mtd/gpmc-onenand.txt b/Documentation/devicetree/bindings/mtd/gpmc-onenand.txt
>>> index b6e8bfd024f4..e9f01a963a0a 100644
>>> --- a/Documentation/devicetree/bindings/mtd/gpmc-onenand.txt
>>> +++ b/Documentation/devicetree/bindings/mtd/gpmc-onenand.txt
>>> @@ -9,13 +9,14 @@ Documentation/devicetree/bindings/memory-controllers/omap-gpmc.txt
>>>  
>>>  Required properties:
>>>  
>>> + - compatible:		"ti,omap2-onenand"
>>
>> Don't you break backward compat by adding this new requirement?
> 
> I was told it is okay in this case as OneNAND conversion to DT is unfinished.
> There was compat fixup code in earlier versions of patchset and it was dropped
> later. If others see it opposite way I can add it back.
> 

If it is possible not to break backward compatibility then we shouldn't.
Only if things are getting real messy because of the poor way the earlier DT
implementation was done we can consider it as an exception.

I thought we rely on GPMC timings entirely from the DT now and so things don't
work with older DT nodes?

>>>   - reg:			The CS line the peripheral is connected to
>>> - - gpmc,device-width	Width of the ONENAND device connected to the GPMC
>>> + - gpmc,device-width:	Width of the ONENAND device connected to the GPMC
>>>  			in bytes. Must be 1 or 2.
>>>  
>>>  Optional properties:
>>>  
>>> - - dma-channel:		DMA Channel index
>>> + - int-gpios:		GPIO specifier for the INT pin.
>>>  
>>>  For inline partition table parsing (optional):
>>>  
>>> @@ -35,6 +36,7 @@ Example for an OMAP3430 board:
>>>  		#size-cells = <1>;
>>>  
>>>  		onenand@0 {
>>> +			compatible = "ti,omap2-onenand";
>>>  			reg = <0 0 0>; /* CS0, offset 0 */
>>>  			gpmc,device-width = <2>;
>>>  

-- 
cheers,
-roger

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

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