USB multiplexer controller class.
USBMuxController is used to control the individual ports on a 8 port USB
hub/switch.This class is responsible for enabling all the GPIO pins on
the needed to control the 8 port USB switch/hub. In order to use this
USB mux controller you need custom hardware setup which connects to the
beaglebone and drives the 8 port relay switch to turn the individual
ports on the USB hub 'on'/'off'.
BUG=chromium:409275
TEST=Tested against a local DUT
Change-Id: If034a63b5b19988e4c25d3f1f7a50fff0eee9303
Reviewed-on: https://chromium-review.googlesource.com/215692
Reviewed-by: Kalin Stoyanov <kalin@chromium.org>
Reviewed-by: harpreet Grewal <harpreet@chromium.org>
Commit-Queue: harpreet Grewal <harpreet@chromium.org>
Tested-by: harpreet Grewal <harpreet@chromium.org>
diff --git a/server/cros/usb_mux_controller.py b/server/cros/usb_mux_controller.py
new file mode 100644
index 0000000..4b8dbdb
--- /dev/null
+++ b/server/cros/usb_mux_controller.py
@@ -0,0 +1,128 @@
+# Copyriht (c) 2014 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import logging
+
+# Following Beaglebone GPIO pins are used to control the 8 port multiplexer.
+MUX_EN = '20'
+MUX_S0 = '115'
+MUX_S1 = '117'
+MUX_S2 = '49'
+
+ENABLE_MUX = '1'
+DISABLE_MUX = '0'
+
+# Various commands used to control the GPIO pins at the kernel level.
+LS_GPIO_DIRECTORY = 'ls /sys/class/gpio'
+EXPORT_GPIO_PIN = 'echo %s > /sys/class/gpio/export'
+SET_GPIO_DIRECTION = 'echo high > /sys/class/gpio/gpio%s/direction'
+SET_GPIO_VALUE = 'echo %s > /sys/class/gpio/gpio%s/value'
+UNEXPORT_GPIO_PIN = 'echo %s > /sys/class/gpio/unexport'
+
+# Values passed to each GPIO pin to enable a specific port.
+# Bit sequence: MUX_S2, MUX_S1, MUX_S0
+# Example: To enable port 5, MUX_S2 will be set to 1, MUX_S1 will be set to 0
+# and MUX_S0 will be set to 1
+ports = {0:'000', 1:'001', 2:'010', 3:'011', 4:'100', 5:'101', 6:'110', 7:'111'}
+
+class USBMuxController(object):
+ """Class to control individual ports on a 8 port USB switch/hub.
+
+ This class is responsible for enabling all the GPIO pins on the beaglebone
+ needed to control the 8 port USB switch/hub. In order to use this USB mux
+ controller you need custom hardware setup which connects to the beaglebone
+ and drives the 8 port relay switch to turn the individual ports on the USB
+ hub 'on'/'off'.
+
+ TODO(harpreet) Write a USB mux hardware design document and provide a link
+ here.
+
+ """
+
+ version = 1
+
+ def __init__(self, host):
+ """Initializes this USB Mux Controller instance.
+
+ @param host: Host where the test will be run.
+
+ """
+ self.host = host
+
+ def __del__(self):
+ """Destructor of USBMuxController.
+
+ Disables all GPIO pins used that control the multiplexer.
+
+ """
+ self.mux_teardown()
+
+ def mux_setup(self):
+ """
+ Enable GPIO pins that control the multiplexer.
+
+ """
+ logging.info('Enable GPIO pins that control the multiplexer.')
+ self.enable_gpio_pins(MUX_EN)
+ self.disable_all_ports()
+ self.enable_gpio_pins(MUX_S2)
+ self.enable_gpio_pins(MUX_S1)
+ self.enable_gpio_pins(MUX_S0)
+
+ def mux_teardown(self):
+ """
+ Disable the multiplexer and unexport all GPIO pins.
+
+ """
+ logging.info('Start USB multiplexer teardown.')
+ self.disable_all_ports()
+ # unexport gpio pins
+ logging.info('Unexport all GPIO pins.')
+ self.host.servo.system(UNEXPORT_GPIO_PIN % MUX_S0)
+ self.host.servo.system(UNEXPORT_GPIO_PIN % MUX_S1)
+ self.host.servo.system(UNEXPORT_GPIO_PIN % MUX_S2)
+ self.host.servo.system(UNEXPORT_GPIO_PIN % MUX_EN)
+ logging.info('Completed USB multiplexer teardown. All USB ports should'
+ 'now be turned off.')
+
+ def enable_gpio_pins(self, pin):
+ """
+ Enables the given GPIO pin by exporting the pin and setting the
+ direction.
+
+ @param pin: GPIO pin to be enabled.
+
+ """
+ if 'gpio' + pin not in self.host.servo.system_output(LS_GPIO_DIRECTORY):
+ self.host.servo.system(EXPORT_GPIO_PIN % pin)
+ self.host.servo.system(SET_GPIO_DIRECTION % pin)
+
+ def enable_port(self, usb_port):
+ """
+ Enables the given port on the USB hub.
+
+ @param usb_port: USB port to be enabled.
+
+ """
+ port = ports[usb_port]
+ logging.info('Enable port %s.', port)
+ self.mux_setup()
+ self.disable_all_ports()
+
+ logging.info('Set GPIO pins to correct logic levels.')
+ self.host.servo.system(SET_GPIO_VALUE % (port[0], MUX_S2))
+ self.host.servo.system(SET_GPIO_VALUE % (port[1], MUX_S1))
+ self.host.servo.system(SET_GPIO_VALUE % (port[2], MUX_S0))
+
+ logging.info('Enable USB multiplexer. Appropriate port should now be'
+ 'enabled')
+ self.host.servo.system(SET_GPIO_VALUE % (ENABLE_MUX, MUX_EN))
+
+ def disable_all_ports(self):
+ """
+ Disables all USB ports that are currently enabled.
+
+ """
+ logging.info('Disable USB ports.')
+ self.host.servo.system(SET_GPIO_VALUE % (DISABLE_MUX, MUX_EN))