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zephyr: Allow using devicetree node labels to construct machine objects.

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Zephyr v3.7.0 added a new feature to allow getting devices by their
devicetree node labels. Use this feature in the MicroPython Zephyr port
to simplify constructing machine module objects, including Pin, SPI,
I2C, and UART. It's still possible to use the more verbose device names
(e.g., gpio@400ff040, i2c@40066000, spi@4002c000), but now we can also
use their devicetree node labels (e.g., gpiob, i2c0, spi0).

Node labels aren't standardized across all SoC families because they
generally try to follow their respective SoC hardware user manual naming
convention, however many boards define common labels for devices routed
to Arduino headers (e.g., arduino_i2c, arduino_serial, and arduino_spi).
That means I2C("arduino_i2c") will work on quite a few boards (>100 in
the main Zephyr tree).

Signed-off-by: Maureen Helm <maureen.helm@analog.com>
This commit is contained in:
Maureen Helm 2024-08-05 12:58:36 -05:00
parent f33df7197e
commit a9803f4711
4 changed files with 28 additions and 23 deletions
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23
docs/zephyr/quickref.rst
View file

@ -36,10 +36,7 @@ Use the :ref:`machine.Pin <machine.Pin>` class::
from machine import Pin from machine import Pin
gpio1 = "gpio@400ff040" # GPIO1 device name pin = Pin(("gpiob", 21), Pin.IN) # create input pin on GPIO port B
gpio2 = "gpio@400ff080" # GPIO2 device name
pin = Pin((gpio1, 21), Pin.IN) # create input pin on GPIO1
print(pin) # print pin port and number print(pin) # print pin port and number
pin.init(Pin.OUT, Pin.PULL_UP, value=1) # reinitialize pin pin.init(Pin.OUT, Pin.PULL_UP, value=1) # reinitialize pin
@ -50,14 +47,14 @@ Use the :ref:`machine.Pin <machine.Pin>` class::
pin.on() # set pin to high pin.on() # set pin to high
pin.off() # set pin to low pin.off() # set pin to low
pin = Pin((gpio1, 21), Pin.IN) # create input pin on GPIO1 pin = Pin(("gpiob", 21), Pin.IN) # create input pin on GPIO port B
pin = Pin((gpio1, 21), Pin.OUT, value=1) # set pin high on creation pin = Pin(("gpiob", 21), Pin.OUT, value=1) # set pin high on creation
pin = Pin((gpio1, 21), Pin.IN, Pin.PULL_UP) # enable internal pull-up resistor pin = Pin(("gpiob", 21), Pin.IN, Pin.PULL_UP) # enable internal pull-up resistor
switch = Pin((gpio2, 6), Pin.IN) # create input pin for a switch switch = Pin(("gpioc", 6), Pin.IN) # create input pin for a switch
switch.irq(lambda t: print("SW2 changed")) # enable an interrupt when switch state is changed switch.irq(lambda t: print("SW2 changed")) # enable an interrupt when switch state is changed
Hardware I2C bus Hardware I2C bus
---------------- ----------------
@ -66,7 +63,7 @@ Hardware I2C is accessed via the :ref:`machine.I2C <machine.I2C>` class::
from machine import I2C from machine import I2C
i2c = I2C("i2c@40066000") # construct an i2c bus i2c = I2C("i2c0") # construct an i2c bus
print(i2c) # print device name print(i2c) # print device name
i2c.scan() # scan the device for available I2C slaves i2c.scan() # scan the device for available I2C slaves
@ -87,11 +84,11 @@ Hardware SPI is accessed via the :ref:`machine.SPI <machine.SPI>` class::
from machine import SPI from machine import SPI
spi = SPI("spi@4002c000") # construct a spi bus with default configuration spi = SPI("spi0") # construct a spi bus with default configuration
spi.init(baudrate=100000, polarity=0, phase=0, bits=8, firstbit=SPI.MSB) # set configuration spi.init(baudrate=100000, polarity=0, phase=0, bits=8, firstbit=SPI.MSB) # set configuration
# equivalently, construct spi bus and set configuration at the same time # equivalently, construct spi bus and set configuration at the same time
spi = SPI("spi@4002c000", baudrate=100000, polarity=0, phase=0, bits=8, firstbit=SPI.MSB) spi = SPI("spi0", baudrate=100000, polarity=0, phase=0, bits=8, firstbit=SPI.MSB)
print(spi) # print device name and bus configuration print(spi) # print device name and bus configuration
spi.read(4) # read 4 bytes on MISO spi.read(4) # read 4 bytes on MISO
@ -149,7 +146,7 @@ Use the :ref:`zsensor.Sensor <zsensor.Sensor>` class to access sensor data::
import zsensor import zsensor
from zsensor import Sensor from zsensor import Sensor
accel = Sensor("fxos8700@1d") # create sensor object for the accelerometer accel = Sensor("fxos8700") # create sensor object for the accelerometer
accel.measure() # obtain a measurement reading from the accelerometer accel.measure() # obtain a measurement reading from the accelerometer

20
ports/zephyr/README.md
View file

@ -107,7 +107,7 @@ To blink an LED:
import time import time
from machine import Pin from machine import Pin
LED = Pin(("gpio@400ff040", 21), Pin.OUT) LED = Pin(("gpiob", 21), Pin.OUT)
while True: while True:
LED.value(1) LED.value(1)
time.sleep(0.5) time.sleep(0.5)
@ -115,18 +115,18 @@ To blink an LED:
time.sleep(0.5) time.sleep(0.5)
The above code uses an LED location for a FRDM-K64F board (port B, pin 21; The above code uses an LED location for a FRDM-K64F board (port B, pin 21;
following Zephyr conventions port are identified by "GPIO_x", where *x* following Zephyr conventions port are identified by their devicetree node
starts from 0). You will need to adjust it for another board (using board's label. You will need to adjust it for another board (using board's reference
reference materials). To execute the above sample, copy it to clipboard, in materials). To execute the above sample, copy it to clipboard, in MicroPython
MicroPython REPL enter "paste mode" using Ctrl+E, paste clipboard, press REPL enter "paste mode" using Ctrl+E, paste clipboard, press Ctrl+D to finish
Ctrl+D to finish paste mode and start execution. paste mode and start execution.
To respond to Pin change IRQs, on a FRDM-K64F board run: To respond to Pin change IRQs, on a FRDM-K64F board run:
from machine import Pin from machine import Pin
SW2 = Pin(("gpio@400ff080", 6), Pin.IN) SW2 = Pin(("gpioc", 6), Pin.IN)
SW3 = Pin(("gpio@400ff000", 4), Pin.IN) SW3 = Pin(("gpioa", 4), Pin.IN)
SW2.irq(lambda t: print("SW2 changed")) SW2.irq(lambda t: print("SW2 changed"))
SW3.irq(lambda t: print("SW3 changed")) SW3.irq(lambda t: print("SW3 changed"))
@ -138,14 +138,14 @@ Example of using I2C to scan for I2C slaves:
from machine import I2C from machine import I2C
i2c = I2C("i2c@40066000") i2c = I2C("i2c0")
i2c.scan() i2c.scan()
Example of using SPI to write a buffer to the MOSI pin: Example of using SPI to write a buffer to the MOSI pin:
from machine import SPI from machine import SPI
spi = SPI("spi@4002c000") spi = SPI("spi0")
spi.init(baudrate=500000, polarity=1, phase=1, bits=8, firstbit=SPI.MSB) spi.init(baudrate=500000, polarity=1, phase=1, bits=8, firstbit=SPI.MSB)
spi.write(b'abcd') spi.write(b'abcd')

2
ports/zephyr/prj.conf
View file

@ -16,6 +16,8 @@ CONFIG_FPU=y
CONFIG_MAIN_STACK_SIZE=4736 CONFIG_MAIN_STACK_SIZE=4736
CONFIG_POLL=y CONFIG_POLL=y
CONFIG_DEVICE_DT_METADATA=y
# Enable sensor subsystem (doesn't add code if not used). # Enable sensor subsystem (doesn't add code if not used).
# Specific sensors should be enabled per-board. # Specific sensors should be enabled per-board.
CONFIG_SENSOR=y CONFIG_SENSOR=y

6
ports/zephyr/zephyr_device.c
View file

@ -31,6 +31,12 @@ const struct device *zephyr_device_find(mp_obj_t name) {
const char *dev_name = mp_obj_str_get_str(name); const char *dev_name = mp_obj_str_get_str(name);
const struct device *dev = device_get_binding(dev_name); const struct device *dev = device_get_binding(dev_name);
#ifdef CONFIG_DEVICE_DT_METADATA
if (dev == NULL) {
dev = device_get_by_dt_nodelabel(dev_name);
}
#endif
if (dev == NULL) { if (dev == NULL) {
#if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE #if MICROPY_ERROR_REPORTING <= MICROPY_ERROR_REPORTING_TERSE
mp_raise_ValueError(MP_ERROR_TEXT("device not found")); mp_raise_ValueError(MP_ERROR_TEXT("device not found"));