1 # Copyright (c) 2012 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 5 ''' 6 USB to I2C controller. 7 ''' 8 9 import glob 10 import logging 11 import os 12 import re 13 import serial 14 import time 15 16 from autotest_lib.client.cros import tty 17 18 # Least significant bit of I2C address. 19 WRITE_BIT = 0 20 READ_BIT = 1 21 22 23 def create_i2c_controller(chipset_config): 24 '''Factory method for I2CController. 25 26 This function is a factory method to create an I2CController instance. 27 28 @param chipset_config: Chipset configuration. 29 @return An I2CController if succeeded. 30 @throws AssertionError if a valid instance cannot be created. 31 ''' 32 if chipset_config.split(':')[0] == 'SC18IM700': 33 usb_uart_driver = chipset_config.split(':')[1] 34 # Try to find a tty terminal that driver name matches usb_uart_driver. 35 tty_path = tty.find_tty_by_driver(usb_uart_driver) 36 if tty_path: 37 return _I2CControllerSC18IM700(tty_path) 38 39 assert False, "Unsupported configuration: %s" % chipset_config 40 41 42 class I2CController(object): 43 ''' 44 The base class of I2C controller. 45 ''' 46 47 # Constants indicate I2C bus status. 48 I2C_OK = 1 49 I2C_NACK_ON_ADDRESS = 2 50 I2C_NACK_ON_DATA = 3 51 I2C_TIME_OUT = 4 52 53 def send_and_check_status(self, slave_addr, int_array): 54 '''Sends data to I2C slave device and checks the bus status. 55 56 @param slave_addr: The address of slave in 7bits format. 57 @param int_array: The data to send in integer array. 58 @param status_check: Whether to check I2C bus status. 59 60 @return An integer indicates I2C bus status. 61 ''' 62 self.send(slave_addr, int_array) 63 return self.read_bus_status() 64 65 def read_bus_status(self): 66 '''Returns the I2C bus status.''' 67 raise NotImplementedError 68 69 def send(self, slave_addr, int_array): 70 '''Sends data to I2C slave device. 71 72 Caller should call read_bus_status() explicitly to confirm whether the 73 data sent successfully. 74 75 @param slave_addr: The address of slave in 7bits format. 76 @param int_array: The data to send in integer array. 77 ''' 78 raise NotImplementedError 79 80 def read(self, slave_addr, bytes_to_read): 81 '''Reads data from I2C slave device. 82 83 @param slave_addr: The address of slave in 7bits format. 84 @param bytes_to_read: The number of bytes to read from device. 85 @return An array of data. 86 ''' 87 raise NotImplementedError 88 89 90 class _I2CControllerSC18IM700(I2CController): 91 ''' 92 Implementation of I2C Controller for NXP SC18IM700. 93 ''' 94 SEC_WAIT_I2C = 0.1 95 96 # Constants from official datasheet. 97 # http://www.nxp.com/documents/data_sheet/SC18IM700.pdf 98 I2C_STATUS = {0b11110000: I2CController.I2C_OK, 99 0b11110001: I2CController.I2C_NACK_ON_ADDRESS, 100 0b11110011: I2CController.I2C_NACK_ON_DATA, 101 0b11111000: I2CController.I2C_TIME_OUT} 102 103 def __init__(self, device_path): 104 '''Connects to NXP via serial port. 105 106 @param device_path: The device path of serial port. 107 ''' 108 self.logger = logging.getLogger('SC18IM700') 109 self.logger.info('Setup serial device... [%s]', device_path) 110 self.device_path = device_path 111 self.serial = serial.Serial(port=self.device_path, 112 baudrate=9600, 113 bytesize=serial.EIGHTBITS, 114 parity=serial.PARITY_NONE, 115 stopbits=serial.STOPBITS_ONE, 116 xonxoff=False, 117 rtscts=True, 118 interCharTimeout=1) 119 self.logger.info('pySerial [%s] configuration : %s', 120 serial.VERSION, self.serial.__repr__()) 121 # Clean the buffer. 122 self.serial.flush() 123 124 def _write(self, data): 125 '''Converts data to bytearray and writes to the serial port.''' 126 self.serial.write(bytearray(data)) 127 self.serial.flush() 128 129 def _read(self): 130 '''Reads data from serial port(Non-Blocking).''' 131 ret = self.serial.read(self.serial.inWaiting()) 132 self.logger.info('Hex and binary dump of datas - ') 133 for char in ret: 134 self.logger.info(' %x - %s', ord(char), bin(ord(char))) 135 return ret 136 137 @staticmethod 138 def _convert_to_8bits_addr(slave_addr_7bits, lsb): 139 '''Converts slave_addr from 7 bits to 8 bits with given LSB.''' 140 assert (slave_addr_7bits >> 7) == 0, "Address must not exceed 7 bits." 141 assert (lsb & ~0x01) == 0, "lsb must not exceed one bit." 142 return (slave_addr_7bits << 1) | lsb 143 144 def read_bus_status(self): 145 cmd = [ord('R'), 0x0A, ord('P')] 146 self._write(cmd) 147 time.sleep(self.SEC_WAIT_I2C) 148 ret = self._read() 149 if (len(ret) == 1) and (ord(ret[0]) in self.I2C_STATUS): 150 return self.I2C_STATUS[ord(ret[0])] 151 raise IOError("I2C_STATUS_READ_FAILED") 152 153 def send(self, slave_addr, int_array): 154 cmd = ([ord('S'), 155 self._convert_to_8bits_addr(slave_addr, WRITE_BIT), 156 len(int_array)] + 157 int_array + [ord('P')]) 158 self._write(cmd) 159 160 def read(self, slave_addr, bytes_to_read): 161 cmd = ([ord('S'), 162 self._convert_to_8bits_addr(slave_addr, READ_BIT), 163 bytes_to_read, 164 ord('P')]) 165 self._write(cmd) 166 time.sleep(self.SEC_WAIT_I2C) 167 return self._read() 168 169 def write_gpio(self, data): 170 self._write([ord('O'), data, ord('P')]) 171 172 def read_gpio(self): 173 self._write([ord('I'), ord('P')]) 174 time.sleep(self.SEC_WAIT_I2C) 175 return self._read() 176 177 def write_register(self, regs, datas): 178 assert len(regs) == len(datas) 179 cmd = [ord('W')] 180 for i in range(len(regs)): 181 cmd.append(regs[i]) 182 cmd.append(datas[i]) 183 cmd.append(ord('P')) 184 self._write(cmd) 185 186 def read_register(self, regs): 187 cmd = [ord('R')] + regs + [ord('P')] 188 self._write(cmd) 189 time.sleep(self.SEC_WAIT_I2C) 190 return self._read() 191
