2016-07-20 14:44 GMT+02:00 Rob Herring <robh@xxxxxxxxxx>: > On Tue, Jul 19, 2016 at 03:36:34PM +0200, Mirza Krak wrote: >> From: Mirza Krak <mirza.krak@xxxxxxxxx> >> >> Document the devicetree bindings for NOR bus driver found on Tegra20 and >> Tegra30 SOCs >> >> Signed-off-by: Mirza Krak <mirza.krak@xxxxxxxxx> >> --- >> .../devicetree/bindings/bus/nvidia,tegra20-nor.txt | 73 ++++++++++++++++++++++ >> 1 file changed, 73 insertions(+) >> create mode 100644 Documentation/devicetree/bindings/bus/nvidia,tegra20-nor.txt >> >> diff --git a/Documentation/devicetree/bindings/bus/nvidia,tegra20-nor.txt b/Documentation/devicetree/bindings/bus/nvidia,tegra20-nor.txt >> new file mode 100644 >> index 0000000..9ee4a66 >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/bus/nvidia,tegra20-nor.txt >> @@ -0,0 +1,73 @@ >> +Device tree bindings for NVIDIA Tegra20/30 NOR Bus >> + >> +The NOR controller supports a number of memory types, including synchronous NOR, >> +asynchronous NOR, and other flash memories with similar interfaces, such as >> +MuxOneNAND. One could also connect high speed devices like FPGAs, DSPs, >> +CAN chips, Wi-Fi chips etc. >> + >> +The actual devices are instantiated from the child nodes of a NOR node. >> + >> +Required properties: >> + >> + - compatible: should be "nvidia,tegra20-nor", "nvidia,tegra30-nor" >> + - reg: Should contain NOR controller registers location and length. >> + - clocks: Must contain one entry, for the module clock. >> + See ../clocks/clock-bindings.txt for details. >> + - resets : Must contain an entry for each entry in reset-names. >> + See ../reset/reset.txt for details. >> + - reset-names : Must include the following entries: >> + - nor >> + - #address-cells: Must be set to 2 to allow memory address translation >> + - #size-cells: Must be set to 1 to allow CS address passing >> + - ranges: Must be set up to reflect the memory layout with four integer >> + values for each chip-select line in use. >> + - nvidia,config: This property represents the SNOR_CONFIG_0 register. >> + >> +Note that the NOR controller does not have any internal chip-select address >> +decoding and if you want to access multiple devices external chip-select >> +decoding must be provided. > > Then what are the 2 chip selects in ranges? > > Rob Those two chip selects are actually a representation of a external decoding logic based on what we use on our board. Even though it the NOR controller only supports one single chip select I wanted to give an example on how one could create more chip-selects with an external logic and what it would look like in the device tree representation. I realize that the bindings should include above explanation or something similar. -- Med Vänliga Hälsningar / Best Regards Mirza Krak mirza.krak@xxxxxxxxx Mobile: +46730280622 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
