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

[Nicolas Ferre]

Le 03/12/2014 15:56, Nicolas Ferre a écrit :
> 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.

Well... no real information, specify right here what a "generic device" is.

>> +				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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