espressif,esp-hosted-mcu (on sd bus)
Description
Espressif ESP-Hosted-MCU Wi-Fi co-processor over SDIO.
An Espressif SoC running esp-hosted-mcu coprocessor firmware, attached to the
host over the SDIO bus. The node is a child of an SDHC slot. Data-ready is
signalled by the coprocessor through an SDIO interrupt register, so no
data-ready GPIO is used.
The coprocessor is normally restarted through a dedicated reset line wired to
a host GPIO, which is the recommended configuration. Where no such line
exists, reset-gpios may be omitted and the coprocessor is left to the power
cycle the SD subsystem performs when it enumerates the card.
That fallback only restarts the coprocessor when both of the following hold,
so check them before relying on it. The host controller driver must act on
SDHC_POWER_OFF and SDHC_POWER_ON, which many do not: a driver that ignores the
power mode still reports success, so an ineffective cycle is indistinguishable
from a real one. The board must also route the coprocessor supply through
whatever the controller switches, and describe it in devicetree; on an
espressif,esp32-sdhc-slot that means giving the slot node a pwr-gpios
property, without which the power mode only gates the card clock and leaves
the coprocessor running.
Where either does not hold, the coprocessor is never actually restarted and
enumeration only succeeds if it happens to be cold-booting already.
The coprocessor firmware version the host expects is a Kconfig option, not a
devicetree property: the firmware is flashed to a separate chip and the driver
queries it at init.
Examples
&sdhc1 {
#address-cells = <1>;
#size-cells = <0>;
esp_hosted_mcu: esp-hosted-mcu@0 {
compatible = "espressif,esp-hosted-mcu";
reg = <0>;
reset-gpios = <&gpio1 22 GPIO_ACTIVE_HIGH>;
status = "okay";
};
};
Properties
Properties not inherited from the base binding file.
Name |
Type |
Details |
|---|---|---|
|
|
Coprocessor reset line, driven by the host. Recommended, and the only
mechanism that restarts the coprocessor on its own. When absent the
coprocessor falls back to the SD power cycle, which is only effective
under the two conditions described above.
|
Deprecated properties not inherited from the base binding file.
(None)
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 “espressif,esp-hosted-mcu” compatible.
Name |
Type |
Details |
|---|---|---|
|
|
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: See Important properties for more information. |
|
|
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 Important properties for more information. |
|
|
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.
See Important properties for more information. |
|
|
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"
|
|
|
Information used to define a mapping (or translation) between the address
space of a bus (the "child address space") and the address space of the
bus node's parent (the "parent address space").
The "ranges" property is typically empty, or a sequence of triplets
(child bus address, parent bus address, length).
If the "ranges" property is empty, it specifies that the parent and child
address spaces are identical and no address translation is required.
If the "ranges" property is not present in a bus node, it is assumed that
no mapping exists between children of the node and the parent address space.
For details, see "2.3.8 ranges" in Devicetree Specification v0.4.
|
|
|
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 Important properties for more information. |
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
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 Important properties for more information. |
|
|
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
|
|
|
Optional names given to each clock provider in the "clocks" property.
|
|
|
This property encodes the number of <u32> 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 encodes the number of <u32> 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.
|
|
|
Indicates that the device is capable of coherent DMA operations.
For details, see "2.3.10 dma-coherent" in Devicetree Specification v0.4.
|
|
|
DMA channel specifiers relevant to the device.
|
|
|
Optional names given to the DMA channel specifiers in the "dmas" property.
|
|
|
IO channel specifiers relevant to the device.
|
|
|
Optional names given to the IO channel specifiers in the "io-channels" property.
|
|
|
Mailbox / IPM channel specifiers relevant to the device.
|
|
|
Optional names given to the mbox specifiers in the "mboxes" property.
|
|
|
Power domain specifiers relevant to the device.
|
|
|
Optional names given to the power domain specifiers in the "power-domains" property.
|
|
|
Number of cells in power-domains property
|
|
|
HW spinlock id relevant to the device.
|
|
|
Optional names given to the hwlock specifiers in the "hwlocks" property.
|
|
|
Do not initialize device automatically on boot. Device should be manually
initialized using device_init().
|
|
|
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.
|
|
|
Automatically configure the device for runtime power management after the
init function runs.
|
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List of power states that will disable this device power.
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