Javier Hi Jon, On 14/03/2013, at 21:43, Jon Hunter <jon-hunter@xxxxxx> wrote: > > On 03/14/2013 03:33 PM, Javier Martinez Canillas wrote: >> 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 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 | 101 ++++++++++++++++++++ >> arch/arm/mach-omap2/gpmc.c | 8 ++ >> 2 files changed, 109 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..8c8be58 >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/net/gpmc-eth.txt >> @@ -0,0 +1,101 @@ >> +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 > > Should we add "reg-io-width" here and say can be 2 or 4 and to refer to > the above description? > I'm not sure about that, this property is not used (neither relevant) to the GPMC driver but is used by the smsc911x driver. Other Ethernet chips could not need that (e.g: supports only 32 bit word accesses) or can have a different property. Uses should check the documentation binding for the connected device. >> + >> +Optional properties for partiton table parsing: >> +- #address-cells: should be set to 1 >> +- #size-cells: should be set to 1 > > Sorry should have caught this earlier. The above is not relevant for > ethernet. > I should have catch that before sending the first version! I took the properties from your gpmc-nor.txt documentation and this is a left over. Will send a v3 removing that. Sorry for being so carelessly... > Otherwise looks good. > > Cheers > Jon Thanks a lot and best regards, Javier-- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
