lkml.org 
[lkml]   [2014]   [Dec]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH v3 06/11] memory: atmel-ebi: add DT bindings documentation
    On Wed, 3 Dec 2014 15:56:54 +0100
    Nicolas Ferre <nicolas.ferre@atmel.com> wrote:

    > 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@free-electrons.com>
    > > ---
    > > .../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.

    Actually that's not a duplicated compatible (see the ebi0/ebi1 at the
    end): sam9263 embeds 2 EBIs, and they have different numbers of chip
    selects, hence the different compatible string.

    I'll add an "atmel,at91sam9rl-ebi" string.

    >
    > > + "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

    Yep, I'll those typos.




    --
    Boris Brezillon, Free Electrons
    Embedded Linux and Kernel engineering
    http://free-electrons.com


    \
     
     \ /
      Last update: 2014-12-03 21:01    [W:5.806 / U:0.180 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site