Subject: Re: [PATCH] booting-without-of: add more bindings for FSL UPM driver

From: Wolfgang Grandegger <[email-masked]>
Date: Mon, 09 Jun 2008 17:19:27 +0200

Segher Boessenkool wrote:
>> +      - chip-delay : may specify a delay value in milliseconds.
> 
> Delay for what?  The binding should say.  "chip-delay" is a bit
> too generic name as well, it could be more descriptive perhaps.

The chip-delay property defines an appropriate maximum delay 
time (tR) required for read operations if the R/B pin is not
connected. It's used as shown below:

+		/* Note: NAND support needs to be enabled in U-Boot */
+		upm@3,0 {
+			#address-cells = <0>;
+			#size-cells = <0>;
+			compatible = "fsl,upm-nand";
+			reg = <3 0x0 0x800>;
+			fsl,upm-addr-offset = <0x10>;
+			fsl,upm-cmd-offset = <0x08>;
+			chip-delay = <25>; // in micro-seconds
+
+			nand@0 {
+				#address-cells = <1>;
+				#size-cells = <1>;
+
+				partition@0 {
+					    label = "fs";
+					    reg = <0x00000000 0x01000000>;
+				};
+			};
+		};
+	};
+

> Shouldn't this be a property of the NAND device anyway, not the
> NAND controller?

Strictly speaking, it's a property of the NAND device. Therefore it 
should be inside the node nand@0, I thhink:

+			nand@0 {
+				#address-cells = <1>;
+				#size-cells = <1>;
+			        chip-delay = <25>; // in micro-seconds
+
+				partition@0 {
+					    label = "fs";
+					    reg = <0x00000000 0x01000000>;
+				};
+			};

Where should that be documented?

Wolfgang.