]> Repositories - Adafruit_Blinka-hackapet.git/blobdiff - src/adafruit_blinka/microcontroller/mcp2221/mcp2221.py
mcp2221: allow empty i2c payload
[Adafruit_Blinka-hackapet.git] / src / adafruit_blinka / microcontroller / mcp2221 / mcp2221.py
index aae81e5088df6d583bf6f142b20cedc10f4d5c11..e5b24bb119c34344b29d5c71a921a1c0097527d6 100644 (file)
@@ -1,35 +1,43 @@
+"""Chip Definition for MCP2221"""
+
+import os
 import time
 import hid
 
+# Here if you need it
+MCP2221_HID_DELAY = float(os.environ.get("BLINKA_MCP2221_HID_DELAY", 0))
+# Use to set delay between reset and device reopen. if negative, don't reset at all
+MCP2221_RESET_DELAY = float(os.environ.get("BLINKA_MCP2221_RESET_DELAY", 0.5))
+
 # from the C driver
 # http://ww1.microchip.com/downloads/en/DeviceDoc/mcp2221_0_1.tar.gz
 # others (???) determined during driver developement
-# pylint: disable=bad-whitespace
-RESP_ERR_NOERR              = 0x00
-RESP_ADDR_NACK              = 0x25
-RESP_READ_ERR               = 0x7F
-RESP_READ_COMPL             = 0x55
-RESP_READ_PARTIAL           = 0x54 # ???
-RESP_I2C_IDLE               = 0x00
-RESP_I2C_START_TOUT         = 0x12
-RESP_I2C_RSTART_TOUT        = 0x17
-RESP_I2C_WRADDRL_TOUT       = 0x23
-RESP_I2C_WRADDRL_WSEND      = 0x21
-RESP_I2C_WRADDRL_NACK       = 0x25
-RESP_I2C_WRDATA_TOUT        = 0x44
-RESP_I2C_RDDATA_TOUT        = 0x52
-RESP_I2C_STOP_TOUT          = 0x62
-
-RESP_I2C_MOREDATA           = 0x43 # ???
-RESP_I2C_PARTIALDATA        = 0x41 # ???
-RESP_I2C_WRITINGNOSTOP      = 0x45 # ???
-
-MCP2221_RETRY_MAX           = 50
-MCP2221_MAX_I2C_DATA_LEN    = 60
-MASK_ADDR_NACK              = 0x40
-# pylint: enable=bad-whitespace
+RESP_ERR_NOERR = 0x00
+RESP_ADDR_NACK = 0x25
+RESP_READ_ERR = 0x7F
+RESP_READ_COMPL = 0x55
+RESP_READ_PARTIAL = 0x54  # ???
+RESP_I2C_IDLE = 0x00
+RESP_I2C_START_TOUT = 0x12
+RESP_I2C_RSTART_TOUT = 0x17
+RESP_I2C_WRADDRL_TOUT = 0x23
+RESP_I2C_WRADDRL_WSEND = 0x21
+RESP_I2C_WRADDRL_NACK = 0x25
+RESP_I2C_WRDATA_TOUT = 0x44
+RESP_I2C_RDDATA_TOUT = 0x52
+RESP_I2C_STOP_TOUT = 0x62
+
+RESP_I2C_MOREDATA = 0x43  # ???
+RESP_I2C_PARTIALDATA = 0x41  # ???
+RESP_I2C_WRITINGNOSTOP = 0x45  # ???
+
+MCP2221_RETRY_MAX = 50
+MCP2221_MAX_I2C_DATA_LEN = 60
+MASK_ADDR_NACK = 0x40
+
 
 class MCP2221:
+    """MCP2221 Device Class Definition"""
 
     VID = 0x04D8
     PID = 0x00DD
@@ -43,63 +51,74 @@ class MCP2221:
     def __init__(self):
         self._hid = hid.device()
         self._hid.open(MCP2221.VID, MCP2221.PID)
-        self._reset()
-        time.sleep(0.25)
+        if MCP2221_RESET_DELAY >= 0:
+            self._reset()
+        self._gp_config = [0x07] * 4  # "don't care" initial value
+        for pin in range(4):
+            self.gp_set_mode(pin, self.GP_GPIO)  # set to GPIO mode
+            self.gpio_set_direction(pin, 1)  # set to INPUT
 
     def _hid_xfer(self, report, response=True):
+        """Perform HID Transfer"""
         # first byte is report ID, which =0 for MCP2221
         # remaing bytes = 64 byte report data
         # https://github.com/libusb/hidapi/blob/083223e77952e1ef57e6b77796536a3359c1b2a3/hidapi/hidapi.h#L185
-        self._hid.write(b'\0' + report + b'\0'*(64-len(report)))
+        self._hid.write(b"\0" + report + b"\0" * (64 - len(report)))
+        time.sleep(MCP2221_HID_DELAY)
         if response:
             # return is 64 byte response report
             return self._hid.read(64)
+        return None
 
-    #----------------------------------------------------------------
+    # ----------------------------------------------------------------
     # MISC
-    #----------------------------------------------------------------
+    # ----------------------------------------------------------------
     def gp_get_mode(self, pin):
-        return self._hid_xfer(b'\x61')[22+pin] & 0x07
+        """Get Current Pin Mode"""
+        return self._hid_xfer(b"\x61")[22 + pin] & 0x07
 
     def gp_set_mode(self, pin, mode):
-        # get current settings
-        current = self._hid_xfer(b'\x61')
+        """Set Current Pin Mode"""
+        # already set to that mode?
+        mode &= 0x07
+        if mode == (self._gp_config[pin] & 0x07):
+            return
+        # update GP mode for pin
+        self._gp_config[pin] = mode
         # empty report, this is safe since 0's = no change
-        report = bytearray(b'\x60'+b'\x00'*63)
+        report = bytearray(b"\x60" + b"\x00" * 63)
         # set the alter GP flag byte
         report[7] = 0xFF
-        # each pin can be set individually
-        # but all 4 get set at once, so we need to
-        # transpose current settings
-        report[8]  = current[22]  # GP0
-        report[9]  = current[23]  # GP1
-        report[10] = current[24]  # GP2
-        report[11] = current[25]  # GP3
-        # then change only the one
-        report[8+pin] = mode & 0x07
+        # add GP setttings
+        report[8] = self._gp_config[0]
+        report[9] = self._gp_config[1]
+        report[10] = self._gp_config[2]
+        report[11] = self._gp_config[3]
         # and make it so
         self._hid_xfer(report)
 
-    def _pretty_report(self, report):
+    def _pretty_report(self, register):
+        report = self._hid_xfer(register)
         print("     0  1  2  3  4  5  6  7  8  9")
         index = 0
         for row in range(7):
-            print("{} : ".format(row), end='')
+            print("{} : ".format(row), end="")
             for _ in range(10):
-                print("{:02x} ".format(report[index]), end='')
+                print("{:02x} ".format(report[index]), end="")
                 index += 1
                 if index > 63:
                     break
             print()
 
     def _status_dump(self):
-        self._pretty_report(self._hid_xfer(b'\x10'))
+        self._pretty_report(b"\x10")
 
     def _sram_dump(self):
-        self._pretty_report(self._hid_xfer(b'\x61'))
+        self._pretty_report(b"\x61")
 
     def _reset(self):
-        self._hid_xfer(b'\x70\xAB\xCD\xEF', response=False)
+        self._hid_xfer(b"\x70\xAB\xCD\xEF", response=False)
+        time.sleep(MCP2221_RESET_DELAY)
         start = time.monotonic()
         while time.monotonic() - start < 5:
             try:
@@ -111,36 +130,50 @@ class MCP2221:
             return
         raise OSError("open failed")
 
-    #----------------------------------------------------------------
+    # ----------------------------------------------------------------
     # GPIO
-    #----------------------------------------------------------------
+    # ----------------------------------------------------------------
     def gpio_set_direction(self, pin, mode):
-        report = bytearray(b'\x50'+b'\x00'*63)  # empty set GPIO report
+        """Set Current GPIO Pin Direction"""
+        if mode:
+            # set bit 3 for INPUT
+            self._gp_config[pin] |= 1 << 3
+        else:
+            # clear bit 3 for OUTPUT
+            self._gp_config[pin] &= ~(1 << 3)
+        report = bytearray(b"\x50" + b"\x00" * 63)  # empty set GPIO report
         offset = 4 * (pin + 1)
-        report[offset] = 0x01                   # set pin direction
-        report[offset+1] = mode                 # to this
+        report[offset] = 0x01  # set pin direction
+        report[offset + 1] = mode  # to this
         self._hid_xfer(report)
 
     def gpio_set_pin(self, pin, value):
-        report = bytearray(b'\x50'+b'\x00'*63)  # empty set GPIO report
+        """Set Current GPIO Pin Value"""
+        if value:
+            # set bit 4
+            self._gp_config[pin] |= 1 << 4
+        else:
+            # clear bit 4
+            self._gp_config[pin] &= ~(1 << 4)
+        report = bytearray(b"\x50" + b"\x00" * 63)  # empty set GPIO report
         offset = 2 + 4 * pin
-        report[offset] = 0x01                   # set pin value
-        report[offset+1] = value                # to this
+        report[offset] = 0x01  # set pin value
+        report[offset + 1] = value  # to this
         self._hid_xfer(report)
 
     def gpio_get_pin(self, pin):
-        resp = self._hid_xfer(b'\x51')
+        """Get Current GPIO Pin Value"""
+        resp = self._hid_xfer(b"\x51")
         offset = 2 + 2 * pin
         if resp[offset] == 0xEE:
             raise RuntimeError("Pin is not set for GPIO operation.")
-        else:
-            return resp[offset]
+        return resp[offset]
 
-    #----------------------------------------------------------------
+    # ----------------------------------------------------------------
     # I2C
-    #----------------------------------------------------------------
+    # ----------------------------------------------------------------
     def _i2c_status(self):
-        resp = self._hid_xfer(b'\x10')
+        resp = self._hid_xfer(b"\x10")
         if resp[1] != 0:
             raise RuntimeError("Couldn't get I2C status")
         return resp
@@ -149,13 +182,14 @@ class MCP2221:
         return self._i2c_status()[8]
 
     def _i2c_cancel(self):
-        resp = self._hid_xfer(b'\x10\x00\x10')
+        resp = self._hid_xfer(b"\x10\x00\x10")
         if resp[1] != 0x00:
             raise RuntimeError("Couldn't cancel I2C")
         if resp[2] == 0x10:
             # bus release will need "a few hundred microseconds"
             time.sleep(0.001)
 
+    # pylint: disable=too-many-arguments
     def _i2c_write(self, cmd, address, buffer, start=0, end=None):
         if self._i2c_state() != 0x00:
             self._i2c_cancel()
@@ -164,30 +198,33 @@ class MCP2221:
         length = end - start
         retries = 0
 
-        while (end - start) > 0:
+        while (end - start) > 0 or not buffer:
             chunk = min(end - start, MCP2221_MAX_I2C_DATA_LEN)
             # write out current chunk
-            resp = self._hid_xfer(bytes([cmd,
-                                         length & 0xFF,
-                                         (length >> 8) & 0xFF,
-                                         address << 1]) +
-                                         buffer[start:(start+chunk)])
+            resp = self._hid_xfer(
+                bytes([cmd, length & 0xFF, (length >> 8) & 0xFF, address << 1])
+                + buffer[start : (start + chunk)]
+            )
             # check for success
             if resp[1] != 0x00:
-                if resp[2] in (RESP_I2C_START_TOUT,
-                               RESP_I2C_WRADDRL_TOUT,
-                               RESP_I2C_WRADDRL_NACK,
-                               RESP_I2C_WRDATA_TOUT,
-                               RESP_I2C_STOP_TOUT):
+                if resp[2] in (
+                    RESP_I2C_START_TOUT,
+                    RESP_I2C_WRADDRL_TOUT,
+                    RESP_I2C_WRADDRL_NACK,
+                    RESP_I2C_WRDATA_TOUT,
+                    RESP_I2C_STOP_TOUT,
+                ):
                     raise RuntimeError("Unrecoverable I2C state failure")
                 retries += 1
                 if retries >= MCP2221_RETRY_MAX:
                     raise RuntimeError("I2C write error, max retries reached.")
                 time.sleep(0.001)
-                continue # try again
+                continue  # try again
             # yay chunk sent!
             while self._i2c_state() == RESP_I2C_PARTIALDATA:
                 time.sleep(0.001)
+            if not buffer:
+                break
             start += chunk
             retries = 0
 
@@ -200,12 +237,14 @@ class MCP2221:
             if usb_cmd_status == 0:
                 break
             if usb_cmd_status == RESP_I2C_WRITINGNOSTOP and cmd == 0x94:
-                break   # this is OK too!
-            if usb_cmd_status in (RESP_I2C_START_TOUT,
-                                  RESP_I2C_WRADDRL_TOUT,
-                                  RESP_I2C_WRADDRL_NACK,
-                                  RESP_I2C_WRDATA_TOUT,
-                                  RESP_I2C_STOP_TOUT):
+                break  # this is OK too!
+            if usb_cmd_status in (
+                RESP_I2C_START_TOUT,
+                RESP_I2C_WRADDRL_TOUT,
+                RESP_I2C_WRADDRL_NACK,
+                RESP_I2C_WRDATA_TOUT,
+                RESP_I2C_STOP_TOUT,
+            ):
                 raise RuntimeError("Unrecoverable I2C state failure")
             time.sleep(0.001)
         else:
@@ -220,10 +259,9 @@ class MCP2221:
         length = end - start
 
         # tell it we want to read
-        resp = self._hid_xfer(bytes([cmd,
-                                     length & 0xFF,
-                                     (length >> 8) & 0xFF,
-                                     (address << 1) | 0x01]))
+        resp = self._hid_xfer(
+            bytes([cmd, length & 0xFF, (length >> 8) & 0xFF, (address << 1) | 0x01])
+        )
 
         # check for success
         if resp[1] != 0x00:
@@ -231,9 +269,9 @@ class MCP2221:
 
         # and now the read part
         while (end - start) > 0:
-            for retry in range(MCP2221_RETRY_MAX):
+            for _ in range(MCP2221_RETRY_MAX):
                 # the actual read
-                resp = self._hid_xfer(b'\x40')
+                resp = self._hid_xfer(b"\x40")
                 # check for success
                 if resp[1] == RESP_I2C_PARTIALDATA:
                     time.sleep(0.001)
@@ -249,67 +287,100 @@ class MCP2221:
                     continue
                 if resp[2] in (RESP_READ_COMPL, RESP_READ_PARTIAL):
                     break
+            else:
+                raise RuntimeError("I2C read error: max retries reached.")
 
             # move data into buffer
             chunk = min(end - start, 60)
-            for i, k in enumerate(range(start, start+chunk)):
+            for i, k in enumerate(range(start, start + chunk)):
                 buffer[k] = resp[4 + i]
             start += chunk
 
-    def i2c_configure(self, baudrate=100000):
-        self._hid_xfer(bytes([0x10,  # set parameters
-                              0x00,  # don't care
-                              0x00,  # no effect
-                              0x20,  # next byte is clock divider
-                              12000000 // baudrate - 3]))
+    # pylint: enable=too-many-arguments
+
+    def _i2c_configure(self, baudrate=100000):
+        """Configure I2C"""
+        self._hid_xfer(
+            bytes(
+                [
+                    0x10,  # set parameters
+                    0x00,  # don't care
+                    0x00,  # no effect
+                    0x20,  # next byte is clock divider
+                    12000000 // baudrate - 3,
+                ]
+            )
+        )
 
     def i2c_writeto(self, address, buffer, *, start=0, end=None):
+        """Write data from the buffer to an address"""
         self._i2c_write(0x90, address, buffer, start, end)
 
     def i2c_readfrom_into(self, address, buffer, *, start=0, end=None):
+        """Read data from an address and into the buffer"""
         self._i2c_read(0x91, address, buffer, start, end)
 
-    def i2c_writeto_then_readfrom(self, address, out_buffer, in_buffer, *,
-                                  out_start=0, out_end=None,
-                                  in_start=0, in_end=None):
+    def i2c_writeto_then_readfrom(
+        self,
+        address,
+        out_buffer,
+        in_buffer,
+        *,
+        out_start=0,
+        out_end=None,
+        in_start=0,
+        in_end=None,
+    ):
+        """Write data from buffer_out to an address and then
+        read data from an address and into buffer_in
+        """
         self._i2c_write(0x94, address, out_buffer, out_start, out_end)
         self._i2c_read(0x93, address, in_buffer, in_start, in_end)
 
     def i2c_scan(self, *, start=0, end=0x79):
+        """Perform an I2C Device Scan"""
         found = []
-        for addr in range(start, end+1):
+        for addr in range(start, end + 1):
             # try a write
             try:
-                self.i2c_writeto(addr, b'\x00')
-            except RuntimeError: # no reply!
+                self.i2c_writeto(addr, b"\x00")
+            except RuntimeError:  # no reply!
                 continue
             # store if success
             found.append(addr)
         return found
 
-    #----------------------------------------------------------------
+    # ----------------------------------------------------------------
     # ADC
-    #----------------------------------------------------------------
+    # ----------------------------------------------------------------
     def adc_configure(self, vref=0):
-        report = bytearray(b'\x60'+b'\x00'*63)
+        """Configure the Analog-to-Digital Converter"""
+        report = bytearray(b"\x60" + b"\x00" * 63)
         report[5] = 1 << 7 | (vref & 0b111)
         self._hid_xfer(report)
 
     def adc_read(self, pin):
-        resp = self._hid_xfer(b'\x10')
+        """Read from the Analog-to-Digital Converter"""
+        resp = self._hid_xfer(b"\x10")
         return resp[49 + 2 * pin] << 8 | resp[48 + 2 * pin]
 
-    #----------------------------------------------------------------
+    # ----------------------------------------------------------------
     # DAC
-    #----------------------------------------------------------------
+    # ----------------------------------------------------------------
     def dac_configure(self, vref=0):
-        report = bytearray(b'\x60'+b'\x00'*63)
+        """Configure the Digital-to-Analog Converter"""
+        report = bytearray(b"\x60" + b"\x00" * 63)
         report[3] = 1 << 7 | (vref & 0b111)
         self._hid_xfer(report)
 
+    # pylint: disable=unused-argument
     def dac_write(self, pin, value):
-        report = bytearray(b'\x60'+b'\x00'*63)
+        """Write to the Digital-to-Analog Converter"""
+        report = bytearray(b"\x60" + b"\x00" * 63)
         report[4] = 1 << 7 | (value & 0b11111)
         self._hid_xfer(report)
 
+    # pylint: enable=unused-argument
+
+
 mcp2221 = MCP2221()