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1# Copyriht (c) 2014 The Chromium OS Authors. All rights reserved.
2# Use of this source code is governed by a BSD-style license that can be
3# found in the LICENSE file.
4
5import logging
6
7# Following Beaglebone GPIO pins are used to control the 8 port multiplexer.
8MUX_EN = '20'
9MUX_S0 = '115'
10MUX_S1 = '117'
11MUX_S2 = '49'
12
13ENABLE_MUX = '1'
14DISABLE_MUX = '0'
15
16# Various commands used to control the GPIO pins at the kernel level.
17LS_GPIO_DIRECTORY = 'ls /sys/class/gpio'
18EXPORT_GPIO_PIN = 'echo %s > /sys/class/gpio/export'
19SET_GPIO_DIRECTION = 'echo high > /sys/class/gpio/gpio%s/direction'
20SET_GPIO_VALUE = 'echo %s > /sys/class/gpio/gpio%s/value'
21UNEXPORT_GPIO_PIN = 'echo %s > /sys/class/gpio/unexport'
22
23# Values passed to each GPIO pin to enable a specific port.
24# Bit sequence: MUX_S2, MUX_S1, MUX_S0
25# Example: To enable port 5, MUX_S2 will be set to 1, MUX_S1 will be set to 0
26# and MUX_S0 will be set to 1
27ports = {0:'000', 1:'001', 2:'010', 3:'011', 4:'100', 5:'101', 6:'110', 7:'111'}
28
29class USBMuxController(object):
30    """Class to control individual ports on a 8 port USB switch/hub.
31
32    This class is responsible for enabling all the GPIO pins on the beaglebone
33    needed to control the 8 port USB switch/hub. In order to use this USB mux
34    controller you need custom hardware setup which connects to the beaglebone
35    and drives the 8 port relay switch to turn the individual ports on the USB
36    hub 'on'/'off'.
37
38    TODO(harpreet) Write a USB mux hardware design document and provide a link
39    here.
40
41    """
42
43    version = 1
44
45    def __init__(self, host):
46        """Initializes this USB Mux Controller instance.
47
48        @param host: Host where the test will be run.
49
50        """
51        self.host = host
52
53    def __del__(self):
54        """Destructor of USBMuxController.
55
56        Disables all GPIO pins used that control the multiplexer.
57
58        """
59        self.mux_teardown()
60
61    def mux_setup(self):
62        """
63        Enable GPIO pins that control the multiplexer.
64
65        """
66        logging.info('Enable GPIO pins that control the multiplexer.')
67        self.enable_gpio_pins(MUX_EN)
68        self.disable_all_ports()
69        self.enable_gpio_pins(MUX_S2)
70        self.enable_gpio_pins(MUX_S1)
71        self.enable_gpio_pins(MUX_S0)
72
73    def mux_teardown(self):
74        """
75        Disable the multiplexer and unexport all GPIO pins.
76
77        """
78        logging.info('Start USB multiplexer teardown.')
79        self.disable_all_ports()
80        # unexport gpio pins
81        logging.info('Unexport all GPIO pins.')
82        self.host.servo.system(UNEXPORT_GPIO_PIN % MUX_S0)
83        self.host.servo.system(UNEXPORT_GPIO_PIN % MUX_S1)
84        self.host.servo.system(UNEXPORT_GPIO_PIN % MUX_S2)
85        self.host.servo.system(UNEXPORT_GPIO_PIN % MUX_EN)
86        logging.info('Completed USB multiplexer teardown. All USB ports should'
87                     'now be turned off.')
88
89    def enable_gpio_pins(self, pin):
90        """
91        Enables the given GPIO pin by exporting the pin and setting the
92        direction.
93
94        @param pin: GPIO pin to be enabled.
95
96        """
97        if 'gpio' + pin not in self.host.servo.system_output(LS_GPIO_DIRECTORY):
98            self.host.servo.system(EXPORT_GPIO_PIN % pin)
99            self.host.servo.system(SET_GPIO_DIRECTION % pin)
100
101    def enable_port(self, usb_port):
102        """
103        Enables the given port on the USB hub.
104
105        @param usb_port: USB port to be enabled.
106
107        """
108        port = ports[usb_port]
109        logging.info('Enable port %s.', port)
110        self.mux_setup()
111        self.disable_all_ports()
112
113        logging.info('Set GPIO pins to correct logic levels.')
114        self.host.servo.system(SET_GPIO_VALUE % (port[0], MUX_S2))
115        self.host.servo.system(SET_GPIO_VALUE % (port[1], MUX_S1))
116        self.host.servo.system(SET_GPIO_VALUE % (port[2], MUX_S0))
117
118        logging.info('Enable USB multiplexer. Appropriate port should now be'
119                     'enabled')
120        self.host.servo.system(SET_GPIO_VALUE % (ENABLE_MUX, MUX_EN))
121
122    def disable_all_ports(self):
123        """
124        Disables all USB ports that are currently enabled.
125
126        """
127        if 'gpio20' in self.host.servo.system_output(LS_GPIO_DIRECTORY):
128            logging.info('Disable USB ports.')
129            self.host.servo.system(SET_GPIO_VALUE % (DISABLE_MUX, MUX_EN))
130