renamed spi/i2c to generic linux since they're not platform specific

[Adafruit_Blinka-hackapet.git] / src / adafruit_blinka / microcontroller / generic_linux / i2c.py

diff --git a/src/adafruit_blinka/microcontroller/generic_linux/i2c.py b/src/adafruit_blinka/microcontroller/generic_linux/i2c.py
new file mode 100644 (file)
index 0000000..e309e9e
--- /dev/null
+++ b/src/adafruit_blinka/microcontroller/generic_linux/i2c.py
@@ -0,0 +1,66 @@
+import Adafruit_PureIO.smbus as smbus
+import time
+
+class I2C:
+    MASTER = 0
+    SLAVE = 1
+    _baudrate = None
+    _mode = None
+    _i2c_bus = None
+
+    def __init__(self, bus_num, mode=MASTER, baudrate=None):
+        if mode != self.MASTER:
+            raise NotImplementedError("Only I2C Master supported!")
+        _mode = self.MASTER
+
+        #if baudrate != None:
+        #    print("I2C frequency is not settable in python, ignoring!")
+        
+        try:
+            self._i2c_bus = smbus.SMBus(bus_num)
+        except FileNotFoundError:
+            raise RuntimeError("I2C Bus #%d not found, check if enabled in config!" % bus_num)
+
+    def scan(self):
+        """Try to read a byte from each address, if you get an OSError it means the device isnt there"""
+        found = []
+        for addr in range(0,0x80):
+            try:
+                self._i2c_bus.read_byte(addr)
+            except OSError:
+                continue
+            found.append(addr)
+        return found
+
+    def writeto(self, address, buffer, *, start=0, end=None, stop=True):
+        if end is None:
+            end = len(buffer)
+        self._i2c_bus.write_bytes(address, buffer[start:end])
+
+    def readfrom_into(self, address, buffer, *, start=0, end=None, stop=True):
+        if end is None:
+            end = len(buffer)
+        
+        readin = self._i2c_bus.read_bytes(address, end-start)
+        for i in range(end-start):
+            buffer[i+start] = readin[i]
+
+    def writeto_then_readfrom(self, address, buffer_out, buffer_in, *,
+                       out_start=0, out_end=None,
+                       in_start=0, in_end=None, stop=False):
+        if out_end is None:
+            out_end = len(buffer_out)        
+        if in_end is None:
+            in_end = len(buffer_in)
+        if stop:
+            # To generate a stop in linux, do in two transactions
+            self.writeto(address, buffer_out, start=out_start, end=out_end, stop=True)
+            self.readfrom_into(address, buffer_in, start=in_start, end=in_end)
+        else:
+            # To generate without a stop, do in one block transaction
+            if out_end-out_start != 1:
+                raise NotImplementedError("Currently can only write a single byte in writeto_then_readfrom")
+            readin = self._i2c_bus.read_i2c_block_data(address, buffer_out[out_start:out_end][0], in_end-in_start)
+            for i in range(in_end-in_start):
+                buffer_in[i+in_start] = readin[i]
+