[PATCH v8 2/2] memory: atmel-ebi: add DT bindings documentation

Boris Brezillon
2016-05-11T10:13:08Z

should be configured by the controller driver through the matrix and smc
syscon regmaps.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
---
.../bindings/memory-controllers/atmel,ebi.txt | 136 +++++++++++++++++++++
1 file changed, 136 insertions(+)
create mode 100644 Documentation/devicetree/bindings/memory-controllers/atmel,ebi.txt

diff --git a/Documentation/devicetree/bindings/memory-controllers/atmel,ebi.txt b/Documentation/devicetree/bindings/memory-controllers/atmel,ebi.txt
new file mode 100644
index 0000000..2fe9b5b
--- /dev/null
+++ b/Documentation/devicetree/bindings/memory-controllers/atmel,ebi.txt
@@ -0,0 +1,136 @@
+* Device tree bindings for Atmel EBI
+
+The External Bus Interface (EBI) controller is a bus where you can connect
+asynchronous (NAND, NOR, SRAM, ....) and synchronous memories (SDR/DDR SDRAMs).
+The EBI provides a glue-less interface to asynchronous memories through the SMC
+(Static Memory Controller).
+
+Required properties:
+
+- compatible: "atmel,at91sam9260-ebi"
+ "atmel,at91sam9261-ebi"
+ "atmel,at91sam9263-ebi0"
+ "atmel,at91sam9263-ebi1"
+ "atmel,at91sam9rl-ebi"
+ "atmel,at91sam9g45-ebi"
+ "atmel,at91sam9x5-ebi"
+ "atmel,sama5d3-ebi"
+
+- reg: Contains offset/length value for EBI memory mapping.
+ This property might contain several entries if the EBI
+ memory range is not contiguous
+
+- #address-cells: Must be 2.
+ The first cell encodes the CS.
+ The second cell encode the offset into the CS memory
+ range.
+
+- #size-cells: Must be set to 1.
+
+- ranges: Encodes CS to memory region association.
+
+- clocks: Clock feeding the EBI controller.
+ See clock-bindings.txt
+
+Children device nodes are representing device connected to the EBI bus.
+
+Required device node properties:
+
+- #reg: Contains the chip-select id, the offset and the length
+ of the memory region requested by the device.
+
+EBI bus configuration will be defined directly in the device subnode.
+
+Optional EBI/SMC properties:
+
+- atmel,smc-bus-width: width of the asynchronous device's data bus
+ 8, 16 or 32.
+ Default to 8 when undefined.
+
+- atmel,smc-byte-access-type "write" or "select" (see Atmel datasheet).
+ Default to "select" when undefined.
+
+- atmel,smc-read-mode "nrd" or "ncs".
+ Default to "ncs" when undefined.
+
+- atmel,smc-write-mode "nwe" or "ncs".
+ Default to "ncs" when undefined.
+
+- atmel,smc-exnw-mode "disabled", "frozen" or "ready".
+ Default to "disabled" when undefined.
+
+- atmel,smc-page-mode enable page mode if present. The provided value
+ defines the page size (supported values: 4, 8,
+ 16 and 32).
+
+- atmel,smc-tdf-mode: "normal" or "optimized". When set to
+ "optimized" the data float time is optimized
+ depending on the next device being accessed
+ (next device setup time is subtracted to the
+ current device data float time).
+ Default to "normal" when undefined.
+
+If at least one atmel,smc- property is defined the following SMC timing
+properties become mandatory. In the other hand, if none of the atmel,smc-
+properties are specified, we assume that the EBI bus configuration will be
+handled by the sub-device driver, and none of those properties should be
+defined.
+
+All the timings are expressed in nanoseconds (see Atmel datasheet for a full
+description).
+
+- atmel,smc-ncs-rd-setup-ns
+- atmel,smc-nrd-setup-ns
+- atmel,smc-ncs-wr-setup-ns
+- atmel,smc-nwe-setup-ns
+- atmel,smc-ncs-rd-pulse-ns
+- atmel,smc-nrd-pulse-ns
+- atmel,smc-ncs-wr-pulse-ns
+- atmel,smc-nwe-pulse-ns
+- atmel,smc-nwe-cycle-ns
+- atmel,smc-nrd-cycle-ns
+- atmel,smc-tdf-ns
+
+Example:
+
+ ebi: ebi@10000000 {
+ compatible = "atmel,sama5d3-ebi";
+ #address-cells = <2>;
+ #size-cells = <1>;
+ atmel,smc = <&hsmc>;
+ atmel,matrix = <&matrix>;
+ reg = <0x10000000 0x10000000
+ 0x40000000 0x30000000>;
+ ranges = <0x0 0x0 0x10000000 0x10000000
+ 0x1 0x0 0x40000000 0x10000000
+ 0x2 0x0 0x50000000 0x10000000
+ 0x3 0x0 0x60000000 0x10000000>;
+ clocks = <&mck>;
+
+ pinctrl-names = "default";
+ pinctrl-0 = <&pinctrl_ebi_addr>;
+
+ nor: flash@0,0 {
+ compatible = "cfi-flash";
+ #address-cells = <1>;
+ #size-cells = <1>;
+ reg = <0x0 0x0 0x1000000>;
+ bank-width = <2>;
+
+ atmel,smc-read-mode = "nrd";
+ atmel,smc-write-mode = "nwe";
+ atmel,smc-bus-width = <16>;
+ atmel,smc-ncs-rd-setup-ns = <0>;
+ atmel,smc-ncs-wr-setup-ns = <0>;
+ atmel,smc-nwe-setup-ns = <8>;
+ atmel,smc-nrd-setup-ns = <16>;
+ atmel,smc-ncs-rd-pulse-ns = <84>;
+ atmel,smc-ncs-wr-pulse-ns = <84>;
+ atmel,smc-nrd-pulse-ns = <76>;
+ atmel,smc-nwe-pulse-ns = <76>;
+ atmel,smc-nrd-cycle-ns = <107>;
+ atmel,smc-nwe-cycle-ns = <84>;
+ atmel,smc-tdf-ns = <16>;
+ };
+ };
+
--
2.7.4