:orphan:
.. raw:: html
.. dtcompatible:: atmel,sam-smc
.. _dtbinding_atmel_sam_smc:
atmel,sam-smc
#############
Vendor: :ref:`Atmel Corporation `
.. note::
An implementation of a driver matching this compatible is available in
:zephyr_file:`drivers/memc/memc_sam_smc.c`.
Description
***********
.. code-block:: none
Atmel Static Memory Controller (SMC).
The SMC allows to interface with static-memory mapped external devices such as
SRAM, PSRAM, PROM, EPROM, EEPROM, LCD Module, NOR Flash and NAND Flash.
The SMC is clocked through the Master Clock (MCK) which is controlled by the
Power Management Controller (PMC).
The SMC controller can have up to 4 children defining the connected external
memory devices. The reg property is set to the device's Chip Select.
Device Tree example taken from the sam4_xplained board:
&smc {
status = "okay";
pinctrl-0 = <&smc_default>;
pinctrl-names = "default";
is66wv51216dbll@0 {
reg = <0>;
atmel,smc-write-mode = "nwe";
atmel,smc-read-mode = "nrd";
atmel,smc-setup-timing = <1 1 1 1>;
atmel,smc-pulse-timing = <6 6 6 6>;
atmel,smc-cycle-timing = <7 7>;
};
};
The above example configures a is66wv51216dbll-55 device. The device is a
low power static RAM which uses NWE and NRD signals connected to the WE
and OE inputs respectively. Assuming that MCK is 120MHz (cpu at full speed)
each MCK cycle will be equivalent to 8ns. Since the memory full cycle is
55ns, as per specification, it requires atmel,smc-cycle-timing of at least
7 pulses (56ns). The atmel,smc-cycle-timing is composed of three parts:
setup, pulse and hold. The setup is used to address the memory. The pulse
is the time used to read/write. The hold is used to release memory. For the
is66wv51216dbll-55 a minimum setup of 5ns (1 cycle) with at least 45ns
(6 cycles) for CPU read/write and no hold time is required.
Note: Since no hold parameter is available at SMC the atmel,smc-cycle-timing
should have additional cycles to accommodate for hold values.
No Hold Time:
cycle-timing (7) = setup (1) + pulse (6) + hold (0)
With 3 Hold Times:
cycle-timing (10) = setup (1) + pulse (6) + hold (3)
Finally, in order to make the memory available you will need to define new
memory device/s in DeviceTree:
sram1: sram@60000000 {
compatible = "zephyr,memory-region", "mmio-sram";
device_type = "memory";
reg = <0x60000000 DT_SIZE_K(512)>;
zephyr,memory-region = "SRAM1";
};
Properties
**********
Top level properties
====================
These property descriptions apply to "atmel,sam-smc"
nodes themselves. This page also describes child node
properties in the following sections.
.. tabs::
.. group-tab:: Node specific properties
Properties not inherited from the base binding file.
.. list-table::
:widths: 1 1 4
:header-rows: 1
* - Name
- Type
- Details
* - ``pinctrl-0``
- ``phandles``
- .. code-block:: none
Pin configuration/s for the first state. Content is specific to the
selected pin controller driver implementation.
* - ``pinctrl-1``
- ``phandles``
- .. code-block:: none
Pin configuration/s for the second state. See pinctrl-0.
* - ``pinctrl-2``
- ``phandles``
- .. code-block:: none
Pin configuration/s for the third state. See pinctrl-0.
* - ``pinctrl-3``
- ``phandles``
- .. code-block:: none
Pin configuration/s for the fourth state. See pinctrl-0.
* - ``pinctrl-4``
- ``phandles``
- .. code-block:: none
Pin configuration/s for the fifth state. See pinctrl-0.
* - ``pinctrl-names``
- ``string-array``
- .. code-block:: none
Names for the provided states. The number of names needs to match the
number of states.
.. group-tab:: Deprecated node specific properties
Deprecated properties not inherited from the base binding file.
(None)
.. group-tab:: Base properties
Properties inherited from the base binding file, which defines
common properties that may be set on many nodes. Not all of these
may apply to the "atmel,sam-smc" compatible.
.. list-table::
:widths: 1 1 4
:header-rows: 1
* - Name
- Type
- Details
* - ``reg``
- ``array``
- .. code-block:: none
Information used to address the device. The value is specific to
the device (i.e. is different depending on the compatible
property).
The "reg" property is typically a sequence of (address, length) pairs.
Each pair is called a "register block". Values are
conventionally written in hex.
For details, see "2.3.6 reg" in Devicetree Specification v0.4.
This property is **required**.
See :ref:`zephyr:dt-important-props` for more information.
* - ``clocks``
- ``phandle-array``
- .. code-block:: none
Information about the device's clock providers. In general, this property
should follow conventions established in the dt-schema binding:
https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/clock/clock.yaml
This property is **required**.
* - ``#address-cells``
- ``int``
- .. code-block:: none
This property encodes the number of cells used by address fields
in "reg" properties in this node's children.
For details, see "2.3.5 #address-cells and #size-cells" in Devicetree
Specification v0.4.
This property is **required**.
Constant value: ``1``
* - ``#size-cells``
- ``int``
- .. code-block:: none
This property encodes the number of cells used by size fields in
"reg" properties in this node's children.
For details, see "2.3.5 #address-cells and #size-cells" in Devicetree
Specification v0.4.
This property is **required**.
* - ``status``
- ``string``
- .. code-block:: none
Indicates the operational status of the hardware or other
resource that the node represents. In particular:
- "okay" means the resource is operational and, for example,
can be used by device drivers
- "disabled" means the resource is not operational and the system
should treat it as if it is not present
For details, see "2.3.4 status" in Devicetree Specification v0.4.
Legal values: ``'ok'``, ``'okay'``, ``'disabled'``, ``'reserved'``, ``'fail'``, ``'fail-sss'``
See :ref:`zephyr:dt-important-props` for more information.
* - ``compatible``
- ``string-array``
- .. code-block:: none
This property is a list of strings that essentially define what
type of hardware or other resource this devicetree node
represents. Each device driver checks for specific compatible
property values to find the devicetree nodes that represent
resources that the driver should manage.
The recommended format is "vendor,device", The "vendor" part is
an abbreviated name of the vendor. The "device" is usually from
the datasheet.
The compatible property can have multiple values, ordered from
most- to least-specific. Having additional values is useful when the
device is a specific instance of a more general family, to allow the
system to match the most specific driver available.
For details, see "2.3.1 compatible" in Devicetree Specification v0.4.
This property is **required**.
See :ref:`zephyr:dt-important-props` for more information.
* - ``reg-names``
- ``string-array``
- .. code-block:: none
Optional names given to each register block in the "reg" property.
For example:
/ {
soc {
#address-cells = <1>;
#size-cells = <1>;
uart@1000 {
reg = <0x1000 0x2000>, <0x3000 0x4000>;
reg-names = "foo", "bar";
};
};
};
The uart@1000 node has two register blocks:
- one with base address 0x1000, size 0x2000, and name "foo"
- another with base address 0x3000, size 0x4000, and name "bar"
* - ``interrupts``
- ``array``
- .. code-block:: none
Information about interrupts generated by the device, encoded as an array
of one or more interrupt specifiers. The format of the data in this property
varies by where the device appears in the interrupt tree. Devices with the same
"interrupt-parent" will use the same format in their interrupts properties.
For details, see "2.4 Interrupts and Interrupt Mapping" in
Devicetree Specification v0.4.
See :ref:`zephyr:dt-important-props` for more information.
* - ``interrupts-extended``
- ``compound``
- .. code-block:: none
Extended interrupt specifier for device, used as an alternative to
the "interrupts" property.
For details, see "2.4 Interrupts and Interrupt Mapping" in
Devicetree Specification v0.4.
* - ``interrupt-names``
- ``string-array``
- .. code-block:: none
Optional names given to each interrupt generated by a device.
The interrupts themselves are defined in either "interrupts" or
"interrupts-extended" properties.
For details, see "2.4 Interrupts and Interrupt Mapping" in
Devicetree Specification v0.4.
* - ``interrupt-parent``
- ``phandle``
- .. code-block:: none
If present, this refers to the node which handles interrupts generated
by this device.
For details, see "2.4 Interrupts and Interrupt Mapping" in
Devicetree Specification v0.4.
* - ``label``
- ``string``
- .. code-block:: none
Human readable string describing the device. Use of this property is
deprecated except as needed on a case-by-case basis.
For details, see "4.1.2 Miscellaneous Properties" in Devicetree
Specification v0.4.
See :ref:`zephyr:dt-important-props` for more information.
* - ``clock-names``
- ``string-array``
- .. code-block:: none
Optional names given to each clock provider in the "clocks" property.
* - ``dmas``
- ``phandle-array``
- .. code-block:: none
DMA channel specifiers relevant to the device.
* - ``dma-names``
- ``string-array``
- .. code-block:: none
Optional names given to the DMA channel specifiers in the "dmas" property.
* - ``io-channels``
- ``phandle-array``
- .. code-block:: none
IO channel specifiers relevant to the device.
* - ``io-channel-names``
- ``string-array``
- .. code-block:: none
Optional names given to the IO channel specifiers in the "io-channels" property.
* - ``mboxes``
- ``phandle-array``
- .. code-block:: none
Mailbox / IPM channel specifiers relevant to the device.
* - ``mbox-names``
- ``string-array``
- .. code-block:: none
Optional names given to the mbox specifiers in the "mboxes" property.
* - ``power-domains``
- ``phandle-array``
- .. code-block:: none
Power domain specifiers relevant to the device.
* - ``power-domain-names``
- ``string-array``
- .. code-block:: none
Optional names given to the power domain specifiers in the "power-domains" property.
* - ``#power-domain-cells``
- ``int``
- .. code-block:: none
Number of cells in power-domains property
* - ``zephyr,deferred-init``
- ``boolean``
- .. code-block:: none
Do not initialize device automatically on boot. Device should be manually
initialized using device_init().
* - ``wakeup-source``
- ``boolean``
- .. code-block:: none
Property to identify that a device can be used as wake up source.
When this property is provided a specific flag is set into the
device that tells the system that the device is capable of
wake up the system.
Wake up capable devices are disabled (interruptions will not wake up
the system) by default but they can be enabled at runtime if necessary.
* - ``zephyr,pm-device-runtime-auto``
- ``boolean``
- .. code-block:: none
Automatically configure the device for runtime power management after the
init function runs.
* - ``zephyr,disabling-power-states``
- ``phandles``
- .. code-block:: none
List of power states that will disable this device power.
Child node properties
=====================
.. list-table::
:widths: 1 1 4
:header-rows: 1
* - Name
- Type
- Details
* - ``reg``
- ``int``
- .. code-block:: none
The device's SMC Chip Select number.
Valid range: 0 - 3
This property is **required**.
See :ref:`zephyr:dt-important-props` for more information.
* - ``atmel,smc-write-mode``
- ``string``
- .. code-block:: none
Select which signal is used for the write operation, either the chip
select (ncs) or a dedicated write enable pin (nwe). The data is put
on the bus during the pulse and hold steps of that signal.
The internal data buffers are switched to output mode after the NCS_WR
or NWE setup time.
This property is **required**.
Legal values: ``'ncs'``, ``'nwe'``
* - ``atmel,smc-read-mode``
- ``string``
- .. code-block:: none
Select which signal is used for the read operation, either the chip
select (ncs) or a dedicated output enable pin (nrd). The data is read
from the bus during the pulse and hold steps of that signal.
This property is **required**.
Legal values: ``'ncs'``, ``'nrd'``
* - ``atmel,smc-setup-timing``
- ``array``
- .. code-block:: none
This value is used to setup memory region (set address). The setup
values is an array of the signals NWE, NCS_WR, NRD and NCS_RD
where each value is configured in terms of MCK cycles. The SMC
controller allows use of setups value of 0 (no delays) when
consecutive reads/writes are used. Each value is encoded in
6 bits where the highest bit adds an offset of 128 cycles.
The effective value for each element is: 128 x setup[5] + setup[4:0]
This property is **required**.
* - ``atmel,smc-pulse-timing``
- ``array``
- .. code-block:: none
This value is used to effectivelly read/write at memory region (pulse phase).
The pulse value is an array of the signals NWE, NCS_WR, NRD and NCS_RD where
each value is configured in terms of MCK cycles and a value of 0 is forbidden.
Each value is encoded in 7 bits where the highest bit adds an offset of 256
cycles. The effective value for each element is: 256 x setup[6] + setup[5:0]
This property is **required**.
* - ``atmel,smc-cycle-timing``
- ``array``
- .. code-block:: none
SMC timing configurations in cycles for the total write and read
length respectively.
This value describes the entire write/read operation timing which
is defined as: cycle = setup + pulse + hold
Value has to be greater or equal to setup + pulse timing and
is encoded in 9 bits where the two highest bits are multiplied
with an offset of 256.
Effective value for each element: 256 x cycle[8:7] + cycle[6:0]
This property is **required**.