144 lines
4.3 KiB
Python
144 lines
4.3 KiB
Python
# SPDX-FileCopyrightText: 2021 Melissa LeBlanc-Williams for Adafruit Industries
|
|
#
|
|
# SPDX-License-Identifier: MIT
|
|
"""am65xx SPI class using PureIO's SPI class"""
|
|
|
|
from Adafruit_PureIO import spi
|
|
|
|
# import Adafruit_PureIO.spi as spi
|
|
from adafruit_blinka.agnostic import detector
|
|
|
|
|
|
class SPI:
|
|
"""SPI Class"""
|
|
|
|
MSB = 0
|
|
LSB = 1
|
|
CPHA = 1
|
|
CPOL = 2
|
|
|
|
baudrate = 100000
|
|
mode = 0
|
|
bits = 8
|
|
|
|
def __init__(self, portid):
|
|
if isinstance(portid, tuple):
|
|
self._spi = spi.SPI(device=portid)
|
|
else:
|
|
self._spi = spi.SPI(device=(portid, 0))
|
|
self.clock_pin = None
|
|
self.mosi_pin = None
|
|
self.miso_pin = None
|
|
self.chip = None
|
|
|
|
# pylint: disable=too-many-arguments,unused-argument
|
|
def init(
|
|
self,
|
|
baudrate=100000,
|
|
polarity=0,
|
|
phase=0,
|
|
bits=8,
|
|
firstbit=MSB,
|
|
sck=None,
|
|
mosi=None,
|
|
miso=None,
|
|
):
|
|
"""Initialize SPI"""
|
|
mode = 0
|
|
if polarity:
|
|
mode |= self.CPOL
|
|
if phase:
|
|
mode |= self.CPHA
|
|
self.baudrate = baudrate
|
|
self.mode = mode
|
|
self.bits = bits
|
|
self.chip = detector.chip
|
|
|
|
# Pins are not used
|
|
self.clock_pin = sck
|
|
self.mosi_pin = mosi
|
|
self.miso_pin = miso
|
|
|
|
# pylint: enable=too-many-arguments,unused-argument
|
|
|
|
# pylint: disable=unnecessary-pass
|
|
def set_no_cs(self):
|
|
"""Setting so that SPI doesn't automatically set the CS pin"""
|
|
# No kernel seems to support this, so we're just going to pass
|
|
pass
|
|
|
|
# pylint: enable=unnecessary-pass
|
|
|
|
@property
|
|
def frequency(self):
|
|
"""Return the current baudrate"""
|
|
return self.baudrate
|
|
|
|
def write(self, buf, start=0, end=None):
|
|
"""Write data from the buffer to SPI"""
|
|
if not buf:
|
|
return
|
|
if end is None:
|
|
end = len(buf)
|
|
try:
|
|
# self._spi.open(self._port, 0)
|
|
self.set_no_cs()
|
|
self._spi.max_speed_hz = self.baudrate
|
|
self._spi.mode = self.mode
|
|
self._spi.bits_per_word = self.bits
|
|
self._spi.writebytes(buf[start:end])
|
|
# self._spi.close()
|
|
except FileNotFoundError:
|
|
print("Could not open SPI device - check if SPI is enabled in kernel!")
|
|
raise
|
|
|
|
def readinto(self, buf, start=0, end=None, write_value=0):
|
|
"""Read data from SPI and into the buffer"""
|
|
if not buf:
|
|
return
|
|
if end is None:
|
|
end = len(buf)
|
|
try:
|
|
# self._spi.open(self._port, 0)
|
|
# self.set_no_cs()
|
|
self._spi.max_speed_hz = self.baudrate
|
|
self._spi.mode = self.mode
|
|
self._spi.bits_per_word = self.bits
|
|
data = self._spi.transfer([write_value] * (end - start))
|
|
for i in range(end - start): # 'readinto' the given buffer
|
|
buf[start + i] = data[i]
|
|
# self._spi.close()
|
|
except FileNotFoundError:
|
|
print("Could not open SPI device - check if SPI is enabled in kernel!")
|
|
raise
|
|
|
|
# pylint: disable=too-many-arguments
|
|
def write_readinto(
|
|
self, buffer_out, buffer_in, out_start=0, out_end=None, in_start=0, in_end=None
|
|
):
|
|
"""Perform a half-duplex write from buffer_out and then
|
|
read data into buffer_in
|
|
"""
|
|
if not buffer_out or not buffer_in:
|
|
return
|
|
if out_end is None:
|
|
out_end = len(buffer_out)
|
|
if in_end is None:
|
|
in_end = len(buffer_in)
|
|
if out_end - out_start != in_end - in_start:
|
|
raise RuntimeError("Buffer slices must be of equal length.")
|
|
try:
|
|
# self._spi.open(self._port, 0)
|
|
# self.set_no_cs()
|
|
self._spi.max_speed_hz = self.baudrate
|
|
self._spi.mode = self.mode
|
|
self._spi.bits_per_word = self.bits
|
|
data = self._spi.transfer(list(buffer_out[out_start : out_end + 1]))
|
|
for i in range((in_end - in_start)):
|
|
buffer_in[i + in_start] = data[i]
|
|
# self._spi.close()
|
|
except FileNotFoundError:
|
|
print("Could not open SPI device - check if SPI is enabled in kernel!")
|
|
raise
|
|
|
|
# pylint: enable=too-many-arguments
|