API docs: added SPI module

Author: dplanella

docs/index.rst

@@ -28,25 +28,20 @@ frequency.
 
    Set up and start the given PWM channel.
 
-   :param channel: PWM channel. It can be specified in the form
+   :param str channel: PWM channel. It can be specified in the form
        of of 'P8_10', or 'EHRPWM2A'.
-   :type channel: str
-   :param duty_cycle: PWM duty cycle. It must have a value from 0 to 100.
-   :type duty_cycle: int
-   :param frequency: PWM frequency, in Hz. It must be greater than 0.
-   :type frequency: int
-   :param polarity: defines whether the value for ``duty_cycle`` affects the
+   :param int duty_cycle: PWM duty cycle. It must have a value from 0 to 100.
+   :param int frequency: PWM frequency, in Hz. It must be greater than 0.
+   :param int polarity: defines whether the value for ``duty_cycle`` affects the
        rising edge or the falling edge of the waveform. Allowed values -- 0
        (rising edge, default) or 1 (falling edge).
-   :type polarity: int
 
 .. function:: stop(channel)
 
    Stop the given PWM channel.
 
-   :param channel: PWM channel. It can be specified in the form
+   :param str channel: PWM channel. It can be specified in the form
        of of 'P8_10', or 'EHRPWM2A'.
-   :type channel: str
 
 .. function:: set_duty_cycle(channel, duty_cycle)
 
@@ -55,11 +50,9 @@ frequency.
    :note: You must have started the PWM channel with :func:`start()`
        once, before changing the duty cycle.
 
-   :param channel: PWM channel. It can be specified in the form
+   :param str channel: PWM channel. It can be specified in the form
        of of 'P8_10', or 'EHRPWM2A'.
-   :type channel: str
-   :param duty_cycle: PWM duty cycle. It must have a value from 0 to 100.
-   :type duty_cycle: int
+   :param int duty_cycle: PWM duty cycle. It must have a value from 0 to 100.
 
 .. function:: set_frequency(channel, frequency)
 
@@ -68,11 +61,9 @@ frequency.
    :note: You must have started the PWM channel with :func:`start()`
        once, before changing the frequency.
 
-   :param channel: PWM channel. It can be specified in the form
+   :param str channel: PWM channel. It can be specified in the form
        of of 'P8_10', or 'EHRPWM2A'.
-   :type channel: str
-   :param frequency: PWM frequency. It must be greater than 0.
-   :type frequency: int
+   :param int frequency: PWM frequency. It must be greater than 0.
 
 .. function:: cleanup()
 
@@ -151,6 +142,103 @@ Example::
 
    Read the raw analog value for the channel.
 
+:mod:`SPI` --- Serial Peripheral Interface
+------------------------------------------
+
+This module defines an object type that allows Serial Peripheral Interface
+(SPI) bus transactions on hosts running the Linux kernel. The host kernel
+must have SPI support and SPI device interface support.
+
+Because the SPI device interface is opened R/W, users of this module 
+usually must have root permissions or be members of a group with granted
+access rights.
+
+Example::
+
+    import Adafruit_BBIO.SPI as SPI
+
+    from Adafruit_BBIO.SPI import SPI
+    # spi = SPI(bus, device) #/dev/spidev<bus>.<device>
+
+    # /dev/spidev0.0
+    spi = SPI(1, 0)
+    print(spi.xfer2([32, 11, 110, 22, 220]))
+    spi.close() 
+
+    # /dev/spidev0.1
+    spi = SPI(1,1)
+    print(spi.xfer2([32, 11, 110, 22, 220]))
+    spi.close() 
+
+    # /dev/spidev1.0
+    spi = SPI(2,0)
+    print(spi.xfer2([32, 11, 110, 22, 220]))
+    spi.close() 
+
+    # /dev/spidev1.1
+    spi = SPI(2,1)
+    print(spi.xfer2([32, 11, 110, 22, 220]))
+    spi.close() 
+
+.. module:: Adafruit_BBIO.SPI
+
+.. class:: SPI(bus, client)
+
+   :param bus: bus number
+   :param client: client number
+   :returns: a new SPI object, optionally connected to the specified SPI
+       device interface.
+   :rtype: :class:`SPI`
+
+   .. method:: open(bus, device)
+
+      Connects the object to the specified SPI device. `open(X, Y)` will open
+      `/dev/spidev-X.Y`
+
+      :param int bus: bus number
+      :param str device: device number
+
+   .. method:: close()
+
+      Disconnects the object from the interface.
+
+   .. method:: readbytes(len)
+
+      Read the specified length of bytes from the SPI device.
+
+      :param int len: length of bytes to read, 1024 maximum.
+      :returns: values read
+      :rtype: list[int]
+
+   .. method:: writebytes(values)
+
+      Write bytes to the SPI device.
+
+      :param values: list of values to write, with a maximum length of 1024.
+      :type values: list[int]
+
+   .. method:: xfer(values[,delay=0])
+
+      xfer([values]) -> [values]
+      Perform an SPI transaction of values. Slave Select (SS or CS) will be
+      released and reactivated between blocks.
+
+      :param values: list of values to transfer, with a maximum length of 1024.
+      :type values: list[int]
+      :param delay: delay in microseconds between blocks.
+      :returns: values transferred
+      :rtype: list[int]
+
+   .. method:: xfer2(values)
+
+      xfer2([values]) -> [values]
+      Perform an SPI transaction of values. Slave Select (SS or CS) will be
+      held active between blocks.
+
+      :param values: list of values to transfer, with a maximum length of 1024.
+      :type values: list[int]
+      :returns: values transferred
+      :rtype: list[int]
 
 Indices and tables
 ==================