Re: [PATCH 2/2] memory: ti-aemif: add bindings for AEMIF driver
From: ivan.khoronzhuk
Date: Tue Dec 03 2013 - 05:52:35 EST
On 11/29/2013 05:10 PM, Santosh Shilimkar wrote:
On Friday 29 November 2013 10:00 AM, Grygorii Strashko wrote:
Hi Kumar Gala,
On 11/22/2013 11:06 PM, Kumar Gala wrote:
On Nov 20, 2013, at 1:03 PM, ivan.khoronzhuk <ivan.khoronzhuk@xxxxxx> wrote:
On 11/20/2013 08:21 PM, Jean-Christophe PLAGNIOL-VILLARD wrote:
+ the chip select signal.
+ Minimum value is 1 (0 treated as 1).
+
+- ti,cs-wsetup: write setup width, ns
+ Time between the beginning of a memory cycle
+ and the activation of write strobe.
+ Minimum value is 1 (0 treated as 1).
+
+- ti,cs-wstrobe: write strobe width, ns
+ Time between the activation and deactivation of
+ the write strobe.
+ Minimum value is 1 (0 treated as 1).
+
+- ti,cs-whold: write hold width, ns
+ Time between the deactivation of the write
+ strobe and the end of the cycle (which may be
+ either an address change or the deactivation of
+ the chip select signal.
+ Minimum value is 1 (0 treated as 1).
+
+If any of the above parameters are absent, current parameter value will be taken
+from the corresponding HW reg.
+
+The name for cs node must be in format csN, where N is the cs number.
this is wired we should use reg instead to represent the cs as done for SPI
or a an other property
Best Regards,
J.
Ok, I will add new property cs-chipselect like following :
ti,cs-chipselect: number of chipselect. Indicates on the
aemif driver which chipselect is used
for accessing the memory.
For compatibles "ti,davinci-aemif" and
"ti,keystone-aemif" it can be in range [0-3].
For compatible "ti,omap-L138-aemif" range is [2-5].
Is it OK?
Why do you need this? As it was mentioned just use reg:
So you’d have something like:
memory-controller@21000A00 {
…
nand:cs2@2 {
reg = <2 0 0>;
ranges;
...
}:
};
I'd prefer to continue with "ti,cs-chipselect" (this is more human friendly definition, as for me),
but if you insist - it can be changed as:
memory-controller@21000A00 {
compatible = "ti,keystone-aemif";
...
cs2 {
compatible = "ti,aemif-cs";
reg = <2>;
...
}
cs0 {
compatible = "ti,aemif-cs";
reg = <0>;
...
}
However, I’m confused by the example in which you have:
+ nand@0,0x8000000 {
+ compatible = "ti,davinci-nand";
+ reg = <0 0x8000000 0x4000000
+ 1 0x0000000 0x0000100>;
+
+ .. see davinci-nand.txt
+ };
What chipselects is this on 0 & 1?
As I described in https://lkml.org/lkml/2013/11/26/282 we are not encoding CS number in reg
- it's memory partition number.
Also, I'd like to note that we *DO NOT introduce* NAND device bindings here.
The Davinci NAND bindings was introduced and accepted more then one year ago, and
we've just updated its a bit (keeping full compatibility) and reused
(see https://lkml.org/lkml/2013/11/21/182).
And the CS number is encoded for Davinci NAND node using standalone property
"ti,davinci-chipselect" and we need to provide (2) two memory ranges to it,
as result we can't encode CS number in "reg" for AEMIF child devices (NAND/NOR/etc),
as it will break bindings compatibility.
In this document, NAND node is used just as an example of child node.
The above should have been really captured in the commit log to get a better
picture. No way on earth, a reviewer can figure out whether this is new bindings
or copy of bindings already used.
Regards,
Santosh
Ok, I will add it.
--
Regards,
Ivan Khoronzhuk
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