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SubjectRe: [PATCH] mtd: nand: document the NAND controller/NAND chip DT representation
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Hi,

On 31/03/16 16:19, Boris Brezillon wrote:
> On Thu, 31 Mar 2016 16:15:26 +0100
> Harvey Hunt <harvey.hunt@imgtec.com> wrote:
>
>> Hi Boris,
>>
>> On 31/03/16 14:57, Boris Brezillon wrote:
>>> Standardize the NAND controller/NAND chip DT representation. Now, all new
>>> NAND controller drivers should comply with this representation, even if
>>> they are only supporting a single NAND chip.
>>>
>>> Existing drivers can keep support for the old representation (where only
>>> the NAND chip was described), but are encouraged to also support the new
>>> one.
>>>
>>> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
>>> ---
>>> Documentation/devicetree/bindings/mtd/nand.txt | 37 +++++++++++++++++++++++++-
>>> 1 file changed, 36 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/mtd/nand.txt b/Documentation/devicetree/bindings/mtd/nand.txt
>>> index b53f92e..fbf5677 100644
>>> --- a/Documentation/devicetree/bindings/mtd/nand.txt
>>> +++ b/Documentation/devicetree/bindings/mtd/nand.txt
>>> @@ -1,4 +1,23 @@
>>> -* MTD generic binding
>>> +* NAND chip and NAND controller generic binding
>>> +
>>> +NAND controller/NAND chip representation:
>>> +
>>> +The NAND controller should be represented with it's own DT node, and all
>>
>> s/it's/its/
>
> Yep, I'll fix that.
>
>>
>>> +NAND chips attached to this controller should be defined as children nodes
>>> +of the NAND controller. This representation should be enforced even for
>>> +simple controllers supporting only one chip.
>>> +
>>> +Mandatory NAND controller properties:
>>> +- #address-cells: depends on your controller. Should at least be 1 to
>>> + encode the CS line id.
>>> +- #size-cells: depends on your controller. Put zero unless you need a
>>> + mapping between CS lines and dedicated memory regions
>>> +
>>> +Optional NAND controller properties
>>> +- ranges: only needed if you need to define a mapping between CS lines and
>>> + memory regions
>>> +
>>> +Optional NAND chip properties:
>>>
>>> - nand-ecc-mode : String, operation mode of the NAND ecc mode.
>>> Supported values are: "none", "soft", "hw", "hw_syndrome", "hw_oob_first",
>>> @@ -19,3 +38,19 @@ errors per {size} bytes".
>>> The interpretation of these parameters is implementation-defined, so not all
>>> implementations must support all possible combinations. However, implementations
>>> are encouraged to further specify the value(s) they support.
>>> +
>>> +Example:
>>> +
>>> + nand-controller {
>>> + #address-cells = <1>;
>>> + #size-cells = <0>;
>>> +
>>> + /* controller specific properties */
>>> +
>>> + nand@0 {
>>> + reg = <0>;
>>> + nand-ecc-mode = "soft_bch";
>>> +
>>> + /* controller specific properties */
>>
>> Did you mean "chip specific properties"?
>
> No, it's really "controller specific properties". Those are properties
> prefixed by the controller vendor name (like 'allwinner,rb' which is
> encoding the native ready/busy pin to be attached to this chip).
>

Okay, I see - I was somewhat confused by it being in the nand chip node,
but I understand what you mean now.

Thanks,

Harvey

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