Besides being used to interface with external memory devices,
the General-Purpose Memory Controller can be used to connect
Pseudo-SRAM devices such as ethernet controllers to OMAP2+
processors using the TI GPMC as a data bus.
This patch allows an ethernet chip to be defined as an GPMC
child device node.
Signed-off-by: Javier Martinez Canillas <javier.martinez@xxxxxxxxxxxxxxx>
---
Changes since v2:
- remove optional #address-cells and #size-cells since are not relevant for
ethernet chips; suggested by Jon Hunter.
Changes since v1:
- Improve the DT binding documentation explaining that even when the GPMC
maximum bus address width is 16-bit, it supports devices with 32-bit
registers address width and the device property especifying this has to
be set accordingly; suggested by Jon Hunter.
Documentation/devicetree/bindings/net/gpmc-eth.txt | 97 ++++++++++++++++++++
arch/arm/mach-omap2/gpmc.c | 8 ++
2 files changed, 105 insertions(+), 0 deletions(-)
create mode 100644 Documentation/devicetree/bindings/net/gpmc-eth.txt
diff --git a/Documentation/devicetree/bindings/net/gpmc-eth.txt b/Documentation/devicetree/bindings/net/gpmc-eth.txt
new file mode 100644
index 0000000..24cb4e4
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/gpmc-eth.txt
@@ -0,0 +1,97 @@
+Device tree bindings for Ethernet chip connected to TI GPMC
+
+Besides being used to interface with external memory devices, the
+General-Purpose Memory Controller can be used to connect Pseudo-SRAM devices
+such as ethernet controllers to processors using the TI GPMC as a data bus.
+
+Ethernet controllers connected to TI GPMC are represented as child nodes of
+the GPMC controller with an "ethernet" name.
+
+All timing relevant properties as well as generic GPMC child properties are
+explained in a separate documents. Please refer to
+Documentation/devicetree/bindings/bus/ti-gpmc.txt
+
+For the properties relevant to the ethernet controller connected to the GPMC
+refer to the binding documentation of the device. For example, the documentation
+for the SMSC 911x is Documentation/devicetree/bindings/net/smsc911x.txt
+
+Child nodes need to specify the GPMC bus address width using the "bank-width"
+property but is possible that an ethernet controller also has a property to
+specify the I/O registers address width. Even when the GPMC has a maximum 16-bit
+address width, it supports devices with 32-bit word registers.
+For example with an SMSC LAN911x/912x controller connected to the TI GPMC on an
+OMAP2+ board, "bank-width = <2>;" and "reg-io-width = <4>;".
+
+Required properties:
+- bank-width: Address width of the device in bytes. GPMC supports 8-bit
+ and 16-bit devices and so must be either 1 or 2 bytes.
+- compatible: Compatible string property for the ethernet child device.
+- gpmc,cs-on: Chip-select assertion time
+- gpmc,cs-rd-off: Chip-select de-assertion time for reads
+- gpmc,cs-wr-off: Chip-select de-assertion time for writes
+- gpmc,oe-on: Output-enable assertion time
+- gpmc,oe-off Output-enable de-assertion time
+- gpmc,we-on: Write-enable assertion time
+- gpmc,we-off: Write-enable de-assertion time
+- gpmc,access: Start cycle to first data capture (read access)
+- gpmc,rd-cycle: Total read cycle time
+- gpmc,wr-cycle: Total write cycle time
+- reg: Chip-select, base address (relative to chip-select)
+ and size of the memory mapped for the device.
+ Note that base address will be typically 0 as this
+ is the start of the chip-select.
+
+Optional properties:
+- gpmc,XXX Additional GPMC timings and settings parameters. See
+ Documentation/devicetree/bindings/bus/ti-gpmc.txt
+
+Example:
+
+gpmc: gpmc@6e000000 {
+ compatible = "ti,omap3430-gpmc";
+ ti,hwmods = "gpmc";
+ reg = <0x6e000000 0x1000>;
+ interrupts = <20>;
+ gpmc,num-cs = <8>;
+ gpmc,num-waitpins = <4>;
+ #address-cells = <2>;
+ #size-cells = <1>;
+
+ ranges = <5 0 0x2c000000 0x1000000>;
+
+ ethernet@5,0 {
+ compatible = "smsc,lan9221", "smsc,lan9115";
+ reg = <5 0 0xff>;
+ bank-width = <2>;
+
+ gpmc,mux-add-data;
+ gpmc,cs-on = <0>;
+ gpmc,cs-rd-off = <186>;
+ gpmc,cs-wr-off = <186>;
+ gpmc,adv-on = <12>;
+ gpmc,adv-rd-off = <48>;
+ gpmc,adv-wr-off = <48>;
+ gpmc,oe-on = <54>;
+ gpmc,oe-off = <168>;
+ gpmc,we-on = <54>;
+ gpmc,we-off = <168>;
+ gpmc,rd-cycle = <186>;
+ gpmc,wr-cycle = <186>;
+ gpmc,access = <114>;
+ gpmc,page-burst-access = <6>;
+ gpmc,bus-turnaround = <12>;
+ gpmc,cycle2cycle-delay = <18>;
+ gpmc,wr-data-mux-bus = <90>;
+ gpmc,wr-access = <186>;
+ gpmc,cycle2cycle-samecsen;
+ gpmc,cycle2cycle-diffcsen;
+
+ interrupt-parent = <&gpio6>;
+ interrupts = <16>;
+ vmmc-supply = <&vddvario>;
+ vmmc_aux-supply = <&vdd33a>;
+ reg-io-width = <4>;
+
+ smsc,save-mac-address;
+ };
+};
diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
index 898b44d..2bc276b 100644
--- a/arch/arm/mach-omap2/gpmc.c
+++ b/arch/arm/mach-omap2/gpmc.c
@@ -1559,6 +1559,14 @@ static int gpmc_probe_dt(struct platform_device *pdev)
}
}
+ for_each_node_by_name(child, "ethernet") {
+ ret = gpmc_probe_generic_child(pdev, child);
+ if (ret < 0) {
+ of_node_put(child);
+ return ret;
+ }
+ }
+
return 0;
}
#else
--
1.7.7.6
--
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