do not set SPI_NO_CS bit when chip is AM3358 #104

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

diff --git a/src/adafruit_blinka/microcontroller/generic_linux/spi.py b/src/adafruit_blinka/microcontroller/generic_linux/spi.py
index b90587316536e105499e17d317a2073079b7fb18..cc19cd89312679e6a09450980f5ab9ffa76c3901 100755 (executable)
--- a/src/adafruit_blinka/microcontroller/generic_linux/spi.py
+++ b/src/adafruit_blinka/microcontroller/generic_linux/spi.py
@@ -1,5 +1,6 @@
 import spidev
 import time
 import spidev
 import time

+from adafruit_blinka.agnostic import detector

 
 class SPI:
     MSB = 0
 
 class SPI:
     MSB = 0


@@ -29,6 +30,19 @@ class SPI:
         self.baudrate = baudrate
         self.mode = mode
         self.bits = bits
         self.baudrate = baudrate
         self.mode = mode
         self.bits = bits

+        self.chip = detector.chip
+
+    def set_no_cs(self):
+        # Linux SPI driver for AM33XX chip in BeagleBone and PocketBeagle
+        # does not support setting SPI_NO_CS mode bit (issue #104)
+        if not self.chip.AM33XX:
+            try:
+                self._spi.no_cs = True  # this doesn't work but try anyways
+            except AttributeError:
+                pass
+        else:
+            # TODO: remove this debug output
+            print("Adafruit_Blinka: generic_linux/spi.py: set_no_cs(): detected AM33XX, SKIP setting no_cs")

 
     def write(self, buf, start=0, end=None):
         if not buf:
 
     def write(self, buf, start=0, end=None):
         if not buf:


@@ -37,10 +51,7 @@ class SPI:
             end = len(buf)
         try:
             self._spi.open(self._port, 0)
             end = len(buf)
         try:
             self._spi.open(self._port, 0)

-            try:
-              self._spi.no_cs = True  # this doesn't work but try anyways
-            except AttributeError:
-              pass
+            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.max_speed_hz = self.baudrate
             self._spi.mode = self.mode
             self._spi.bits_per_word = self.bits


@@ -50,21 +61,18 @@ class SPI:
             print("Could not open SPI device - check if SPI is enabled in kernel!")
             raise
 
             print("Could not open SPI device - check if SPI is enabled in kernel!")
             raise
 

-    def readinto(self, buf, start=0, end=None):
+    def readinto(self, buf, start=0, end=None, write_value=0):

         if not buf:
             return
         if end is None:
             end = len(buf)
         try:
             self._spi.open(self._port, 0)
         if not buf:
             return
         if end is None:
             end = len(buf)
         try:
             self._spi.open(self._port, 0)

-            try:
-              self._spi.no_cs = True  # this doesn't work but try anyways
-            except AttributeError:
-              pass
+            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.max_speed_hz = self.baudrate
             self._spi.mode = self.mode
             self._spi.bits_per_word = self.bits

-            data = self._spi.readbytes(end-start)
+            data = self._spi.xfer([write_value]*(end-start))

             for i in range(end-start):  # 'readinto' the given buffer
               buf[start+i] = data[i]
             self._spi.close()
             for i in range(end-start):  # 'readinto' the given buffer
               buf[start+i] = data[i]
             self._spi.close()


@@ -77,17 +85,14 @@ class SPI:
         if not buffer_out or not buffer_in:
             return
         if out_end is None:
         if not buffer_out or not buffer_in:
             return
         if out_end is None:

-            out_end = len(buffer_out)        
+            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)
         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)

-            try:
-                self._spi.no_cs = True  # this doesn't work but try anyways
-            except AttributeError:
-                pass
+            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.max_speed_hz = self.baudrate
             self._spi.mode = self.mode
             self._spi.bits_per_word = self.bits