zephyr,swdp-gpio
Vendor: Zephyr-specific binding
Note
An implementation of a driver matching this compatible is available in drivers/dp/swdp_bitbang.c.
Description
This is a representation of the Serial Wire Debug Port interface
implementation by GPIO bit-banging.
Schematic using dual-supply bus transceiver and separate dout and dnoe pins
VCC_3V3 VCC_REF
^ ^
| +-------------+ |
+-------|vcca vccb|-----+
| |
clk-gpios -------|a b|-------------- SWD CLK
| |
noe-gpios -------|dir gnd|-----+
+-------------+ |
74LVC1T45 v
GND
VCC_3V3 VCC_REF
^ ^
| +-------------+ |
+-------|vcca vccb|-----+
| |
dio-gpios -------|a b|------------*- SWD DIO
| | |
+-------|dir gnd|-----+ |
| +-------------+ | |
v 74LVC1T45 v |
GND GND |
|
|
VCC_3V3 VCC_REF |
^ ^ |
| +-------------+ | |
+-------|vcca vccb|-----+ |
| | |
dout-gpios -------|a b|------------+
| |
dnoe-gpios -------|dir gnd|-----+
+-------------+ |
74LVC1T45 v
GND
Direct connection using only dio pin for SWD DIO.
clk-gpios ------------------------------------ SWD CLK
dio-gpios ------------------------------------ SWD DIO
Of course, bidirectional bus transceiver between dio and SWD DIO can also be
used together with noe pin to enable/disable transceivers.
Properties
Properties not inherited from the base binding file.
Name |
Type |
Details |
|---|---|---|
|
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GPIO pin used for SWCLK output
This property is required. |
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GPIO pin used for SWDIO input. This pin is also used for the SWDIO output
if separate output pin is not defined.
This property is required. |
|
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Optional GPIO pin used for SWDIO output.
|
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GPIO pin used to disable the SWDIO output buffer behind optional
pin dout-gpios.
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Optional pin to disable all bus transceivers if any are present.
|
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Optional GPIO pin used for RESET output.
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Number of processor cycles for I/O Port write operations.For example, the
GPIO clock may be different from the CPU clock. This can usually be
found in the SoC documentation.
This property is required. |
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 “zephyr,swdp-gpio” compatible.
Name |
Type |
Details |
|---|---|---|
|
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indicates the operational status of a device
Legal values: See Important properties for more information. |
|
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compatible strings
This property is required. See Important properties for more information. |
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register space
See Important properties for more information. |
|
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name of each register space
|
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interrupts for device
See Important properties for more information. |
|
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extended interrupt specifier for device
|
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name of each interrupt
|
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phandle to interrupt controller node
|
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Human readable string describing the device (used as device_get_binding() argument)
See Important properties for more information. This property is deprecated. |
|
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Clock gate information
|
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name of each clock
|
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number of address cells in reg property
|
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number of size cells in reg property
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DMA channels specifiers
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Provided names of DMA channel specifiers
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IO channels specifiers
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Provided names of IO channel specifiers
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mailbox / IPM channels specifiers
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Provided names of mailbox / IPM channel specifiers
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Power domain specifiers
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Provided names of power domain specifiers
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Number of cells in power-domains property
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Do not initialize device automatically on boot. Device should be manually
initialized using device_init().
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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.
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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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