On 16/06/15 23:53, Stephen Boyd wrote:

On 05/21/2015 09:44 AM, Srinivas Kandagatla wrote:

quoted

diff --git a/Documentation/devicetree/bindings/nvmem/nvmem.txt b/Documentation/devicetree/bindings/nvmem/nvmem.txt
new file mode 100644
index 0000000..ecea654
--- /dev/null
+++ b/Documentation/devicetree/bindings/nvmem/nvmem.txt

@@ -0,0 +1,84 @@
+= NVMEM Data Device Tree Bindings =
+
+This binding is intended to represent the location of hardware
+configuration data stored in NVMEMs.

It would be worthwhile spelling out what NVMEM stands for.

quoted

+
+On a significant proportion of boards, the manufacturer has stored
+some data on NVMEM, for the OS to be able to retrieve these information
+and act upon it. Obviously, the OS has to know about where to retrieve
+these data from, and where they are stored on the storage device.
+
+This document is here to document this.
+
+= Data providers =
+Contains bindings specific to provider drivers and data cells as children
+to this node.

children of this node?

Yep, will fix the text

quoted

+
+Optional properties:
+ read-only: Mark the provider as read only.
+
+= Data cells =
+These are the child nodes of the provider which contain data cell
+information like offset and size in nvmem provider.
+
+Required properties:
+reg:	specifies the offset in byte within that storage device, start bit
+	in the byte and the length in bits of the data we care about.
+	There could be more then one offset-length pairs in this property.

s/then/than/

Yep.

quoted

+
+Optional properties:
+
+bit-offset: specifies the offset in bit within the address range specified
+	by reg property. Can take values from 0-7.
+nbits: specifies number of bits this cell occupies starting from bit-offset.
+

Hopefully the consumer knows the endianness of the data stored.

As we read byte-byte, does it matter, as long as consumer gets them in 
the same order as its stored.

quoted

+For example:
+
+	/* Provider */
+	qfprom: qfprom at 00700000 {
+		...
+
+		/* Data cells */
+		tsens_calibration: calib at 404 {
+			reg = <0x404 0x10>;
+		};
+
+		tsens_calibration_bckp: calib_bckp at 504 {
+			reg = <0x504 0x11>;
+			bit-offset = 6;
+			nbits = 128;
+		};
+
+		pvs_version: pvs-version at 6 {
+			reg = <0x6 0x2>
+			bit-offset = 7;
+			nbits = 2;
+		};
+
+		speed_bin: speed-bin at c{
+			reg = <0xc 0x1>;
+			bit-offset = 2;
+			nbits	= 3;
+
+		};
+		...
+	};
+
+= Data consumers =
+Are device nodes which consume nvmem data cells/providers.
+
+Required-properties:
+nvmem-cell: list of phandle to the nvmem data cells.
+nvmem-cell-names: names for the each nvmem-cell specified
+
+Optional-properties:
+nvmem	: list of phandles to nvmem providers.
+nvmem-names: names for the each nvmem provider.

Is nvmem-names required if nvmem is used?

Yes, will fix it.