src/adafruit_blinka/microcontroller/ftdi_mpsse/mpsse/i2c.py

   1 # SPDX-FileCopyrightText: 2021 Melissa LeBlanc-Williams for Adafruit Industries
   2 #
   3 # SPDX-License-Identifier: MIT
   4 """I2C Class for FTDI MPSSE"""
   5 from adafruit_blinka.microcontroller.ftdi_mpsse.mpsse.pin import Pin
   6 from adafruit_blinka.microcontroller.ftdi_mpsse.mpsse.url import (
   7     get_ft232h_url,
   8     get_ft2232h_url,
   9 )
  10
  11
  12 class I2C:
  13     """Custom I2C Class for FTDI MPSSE"""
  14
  15     MASTER = 0
  16     SLAVE = 1
  17     _mode = None
  18
  19     # pylint: disable=unused-argument
  20     def __init__(self, i2c_id=None, mode=MASTER, baudrate=None, frequency=400000):
  21         if mode != self.MASTER:
  22             raise NotImplementedError("Only I2C Master supported!")
  23         _mode = self.MASTER
  24
  25         # change GPIO controller to I2C
  26         # pylint: disable=import-outside-toplevel
  27         from pyftdi.i2c import I2cController
  28
  29         # pylint: enable=import-outside-toplevel
  30
  31         self._i2c = I2cController()
  32         if i2c_id is None:
  33             self._i2c.configure(get_ft232h_url(), frequency=frequency)
  34         else:
  35             self._i2c.configure(get_ft2232h_url(i2c_id), frequency=frequency)
  36         Pin.mpsse_gpio = self._i2c.get_gpio()
  37
  38     def scan(self):
  39         """Perform an I2C Device Scan"""
  40         return [addr for addr in range(0x79) if self._i2c.poll(addr)]
  41
  42     def writeto(self, address, buffer, *, start=0, end=None, stop=True):
  43         """Write data from the buffer to an address"""
  44         end = end if end else len(buffer)
  45         port = self._i2c.get_port(address)
  46         port.write(buffer[start:end], relax=stop)
  47
  48     def readfrom_into(self, address, buffer, *, start=0, end=None, stop=True):
  49         """Read data from an address and into the buffer"""
  50         end = end if end else len(buffer)
  51         port = self._i2c.get_port(address)
  52         result = port.read(len(buffer[start:end]), relax=stop)
  53         for i, b in enumerate(result):
  54             buffer[start + i] = b
  55
  56     # pylint: disable=unused-argument
  57     def writeto_then_readfrom(
  58         self,
  59         address,
  60         buffer_out,
  61         buffer_in,
  62         *,
  63         out_start=0,
  64         out_end=None,
  65         in_start=0,
  66         in_end=None,
  67         stop=False,
  68     ):
  69         """Write data from buffer_out to an address and then
  70         read data from an address and into buffer_in
  71         """
  72         out_end = out_end if out_end else len(buffer_out)
  73         in_end = in_end if in_end else len(buffer_in)
  74         port = self._i2c.get_port(address)
  75         result = port.exchange(
  76             buffer_out[out_start:out_end], in_end - in_start, relax=True
  77         )
  78         for i, b in enumerate(result):
  79             buffer_in[in_start + i] = b
  80
  81     # pylint: enable=unused-argument