Re: [PATCH v3 06/11] memory: atmel-ebi: add DT bindings documentation

[Nicolas Ferre]

Le 01/12/2014 11:27, Boris Brezillon a écrit :
> The EBI (External Bus Interface) is used to access external peripherals
> (NOR, SRAM, NAND, and other specific devices like ethernet controllers).
> Each device is assigned a CS line and an address range and can have its
> own configuration (timings, access mode, bus width, ...).
> This driver provides a generic DT binding to configure a device according
> to its requirements.
> For specific device controllers (like the NAND one) the SMC timings
> should be configured by the controller driver through the matrix and smc
> syscon regmaps.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
> ---
>  .../bindings/memory-controllers/atmel-ebi.txt      | 155 +++++++++++++++++++++
>  1 file changed, 155 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..3749ea1
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/memory-controllers/atmel-ebi.txt
> @@ -0,0 +1,155 @@
> +* 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 though the SMC
> +(Static Memory Controller).
> +Synchronous memories (and some asynchronous memories like NANDs) can be
> +attached to specialized controllers which are responsible for configuring the
> +bus appropriately according to the connected device.
> +In the other hand, the bus interface can be automated for simple asynchronous
> +devices.
> +
> +Required properties:
> +
> +- compatible:		"atmel,at91sam9260-ebi"
> +			"atmel,at91sam9261-ebi"
> +			"atmel,at91sam9263-ebi0"
> +			"atmel,at91sam9263-ebi1"

Ditto: 9263 twice.

> +			"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
> +
> +Child chip-select (cs) nodes contain the memory devices nodes connected to
> +such as NOR (e.g. cfi-flash) and NAND.
> +There might be board specific devices like FPGAs.
> +You'll define you device requirements in these child nodes.
> +
> +Required child cs node properties:
> +
> +- #address-cells:	Must be 2.
> +
> +- #size-cells:		Must be 1.
> +
> +- ranges:		Empty property indicating that child nodes can inherit
> +			memory layout.
> +
> +Optional child cs node properties:
> +- atmel,generic-dev		boolean property specifying if the device is
> +				a generic device.
> +				The following properties are only parsed if
> +				this property is present.
> +				Specialized devices are attached to specialized
> +				controllers which are responsible for
> +				configuring the bus appropriately.
> +				Here are some examples of specialized
> +				controllers: NAND, CompactFlash, SDR-SDRAM.
> +
> +- atmel,bus-width:		width of the asynchronous device's data bus
> +				8, 16 or 32.
> +				8 if not present.
> +
> +- atmel,byte-access-type	"write" or "select" (see Atmel datasheet).
> +				"select" if not present.
> +
> +- atmel,read-mode		"nrd" or "ncs".
> +				"ncs" is not present.
> +
> +- atmel,write-mode		"nwe" or "ncs".
> +				"ncs" is not present.
> +
> +- atmel,exnw-mode		"disabled", "frozen" or "ready".
> +				"disabled" if not present.
> +
> +- atmel,page-mode		enable page mode if present. The provided value
> +				defines the page size (supported values: 4, 8,
> +				16 and 32).
> +
> +Optional device timings expressed in nanoseconds (if the property is not
> +present 0 is assumed):
> +
> +- atmel,ncs-rd-setup-ns
> +- atmel,nrd-setup-ns
> +- atmel,ncs-wr-setup-ns
> +- atmel,nwe-setup-ns
> +- atmel,ncs-rd-pulse-ns
> +- atmel,nrd-pulse-ns
> +- atmel,ncs-wr-pulse-ns
> +- atmel,nwe-pulse-ns
> +- atmel,nwe-cycle-ns
> +- atmel,nrd-cycle-ns
> +- atmel,tdf-ns
> +
> +- atmel,tdf-optimized		data float optimized mode. If present the data
> +				float time is optimized depending on the next
> +				device being accessed (next device setup
> +				time is substracted to the current devive data

Typo: subtract, device

> +				float time).
> +
> +
> +
> +Example:
> +
> +	ebi: ebi@10000000 {
> +		compatible = "atmel,sama5d3-ebi", "simple-bus";
> +		#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>;
> +
> +		cs@0 {
> +			#address-cells = <2>;
> +			#size-cells = <1>;
> +			ranges;
> +			atmel,generic-dev;
> +			atmel,read-mode = "nrd";
> +			atmel,write-mode = "nwe";
> +			atmel,bus-width = <16>;
> +			atmel,ncs-rd-setup-ns = <0>;
> +			atmel,ncs-wr-setup-ns = <0>;
> +			atmel,nwe-setup-ns = <8>;
> +			atmel,nrd-setup-ns = <16>;
> +			atmel,ncs-rd-pulse-ns = <84>;
> +			atmel,ncs-wr-pulse-ns = <84>;
> +			atmel,nrd-pulse-ns = <76>;
> +			atmel,nwe-pulse-ns = <76>;
> +			atmel,nrd-cycle-ns = <107>;
> +			atmel,nwe-cycle-ns = <84>;
> +			atmel,tdf-ns = <16>;
> +
> +			nor: flash@0,0 {
> +				compatible = "cfi-flash";
> +				#address-cells = <1>;
> +				#size-cells = <1>;
> +				reg = <0x0 0x0 0x1000000>;
> +				bank-width = <2>;
> +			};
> +		};
> +	};
> +
> 


-- 
Nicolas Ferre
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