Add documentation for new subnode properties, allowing bank configuration.
Based on u-boot implementation, but heavily reworked.
Also, fix size of SROMc mapping in the example.
Signed-off-by: Pavel Fedin <p.fe...@samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlow...@samsung.com>
---
.../bindings/arm/samsung/exynos-srom.txt | 73 +++++++++++++++++++++-
1 file changed, 71 insertions(+), 2 deletions(-)
diff --git a/Documentation/devicetree/bindings/arm/samsung/exynos-srom.txt
b/Documentation/devicetree/bindings/arm/samsung/exynos-srom.txt
index 33886d5..07c8507 100644
--- a/Documentation/devicetree/bindings/arm/samsung/exynos-srom.txt
+++ b/Documentation/devicetree/bindings/arm/samsung/exynos-srom.txt
@@ -5,8 +5,77 @@ Required properties:
- reg: offset and length of the register set
-Example:
+Optional properties:
+The SROM controller can be used to attach external peripherals. In this case
+extra properties, describing the bus behind it, should be specified as below:
+
+- #address-cells: Must be set to 2 to allow device address translation.
+ Address is specified as (bank#, offset).
+
+- #size-cells: Must be set to 1 to allow device size passing
+
+- ranges: Must be set up to reflect the memory layout with four integer values
+ per bank:
+ <bank-number> 0 <parent address of bank> <size>
+
+Sub-nodes:
+The actual device nodes should be added as subnodes to the SROMc node. These
+subnodes, except regular device specification, should contain the following
+properties, describing configuration of the relevant SROM bank:
+
+Required properties:
+- reg: bank number, base address (relative to start of the bank) and size of
+ the memory mapped for the device. Note that base address will be
+ typically 0 as this is the start of the bank.
+
+- samsung,srom-timing : array of 6 integers, specifying bank timings in the
+ following order: Tacp, Tcah, Tcoh, Tacc, Tcos, Tacs.
+ Each value is specified in cycles and has the following
+ meaning and valid range:
+ Tacp : Page mode access cycle at Page mode (0 - 15)
+ Tcah : Address holding time after CSn (0 - 15)
+ Tcoh : Chip selection hold on OEn (0 - 15)
+ Tacc : Access cycle (0 - 31, the actual time is N + 1)
+ Tcos : Chip selection set-up before OEn (0 - 15)
+ Tacs : Address set-up before CSn (0 - 15)
+
+Optional properties:
+- reg-io-width : data width in bytes (1 or 2). If omitted, default of 1 is
used.
+
+- samsung,srom-page-mode : page mode configuration for the bank:
+ 0 - normal (one data)
+ 1 - four data
+ If omitted, default of 0 is used.
+
+Example: basic definition, no banks are configured
+ sromc@12570000 {
+ compatible = "samsung,exynos-srom";
+ reg = <0x12570000 0x14>;
+ };
+
+Example: SROMc with SMSC911x ethernet chip on bank 3
sromc@12570000 {
+ #address-cells = <2>;
+ #size-cells = <1>;
+ ranges = <0 0 0x04000000 0x20000 // Bank0
+ 1 0 0x05000000 0x20000 // Bank1
+ 2 0 0x06000000 0x20000 // Bank2
+ 3 0 0x07000000 0x20000>; // Bank3
+
compatible = "samsung,exynos-srom";
- reg = <0x12570000 0x10>;
+ reg = <0x12570000 0x14>;
+
+ ethernet@3 {
+ compatible = "smsc,lan9115";
+ reg = <3 0 0x10000>; // Bank 3, offset = 0
+ phy-mode = "mii";
+ interrupt-parent = <&gpx0>;
+ interrupts = <5 8>;
+ reg-io-width = <2>;
+ smsc,irq-push-pull;
+ smsc,force-internal-phy;
+
+ samsung,srom-page-mode = <1>;
+ samsung,srom-timing = <9 12 1 9 1 1>;
+ };
};
--
2.4.4
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