103 lines
2.9 KiB
Python
Executable file
103 lines
2.9 KiB
Python
Executable file
#!/usr/bin/env python3
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###
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# Dependencies: Linux, python3, python3-smbus
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# Usage: `sudo ./set_lp8550_slope.py`
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#
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# Default slope is 0b101=200ms, can be adjusted below
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# Tested with Ubuntu 20.04 on A1466 2013
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# All original EEPROM registers value:
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# - A0: 0b01111111
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# - A1: 0b10110101
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# - A2: 0b10111111
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# - A3: 0b01111011
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# - A4: 0b00101000
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# - A5: 0b11001111
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# - A6: 0b01100100
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# - A7: 0b00101101
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###
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import time
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import smbus2
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config = {
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'smbus_address': 0, # SMBus address, can use `i2cdetect -l` to find it
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'device_address': 0x2C, # LP8550 7 bits address
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'slope': (1, 0, 1) # The new slope to set, MSB first, see lp8550 datasheet 8.6.2.3 SLOPE
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}
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lp8550_regs = {
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'EEPROMControl': 0x72,
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'EEPROMAddress1': 0xA1 # default value for this register is 0b10110101 on original 820-3437
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}
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def bitstolist(val, regsize=8):
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return [(val >> i) & 0b1 for i in range(0, regsize)]
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def listtobits(l, regsize=8):
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val = 0
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for i in range(0, regsize):
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val += l[i] << i
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return val
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def read_reg(bus, dev_address, reg_name):
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return bitstolist(bus.read_byte_data(dev_address, lp8550_regs[reg_name]))
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def write_reg(bus, dev_address, reg_name, reg):
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print(f'Writing { listtobits(reg)} to {dev_address}, {lp8550_regs[reg_name]}')
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bus.write_byte_data(dev_address, lp8550_regs[reg_name], listtobits(reg))
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def get_slope(bus, dev_address):
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return read_reg(bus, dev_address, 'EEPROMAddress1')[0:3][::-1]
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def set_slope(bus, dev_address, slope):
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print('Original slope: ', get_slope(bus, dev_address))
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EEPROMAddress1 = read_reg(bus, dev_address, 'EEPROMAddress1')
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EEPROMAddress1[0:3] = slope[::-1]
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write_reg(bus, dev_address, 'EEPROMAddress1', EEPROMAddress1)
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print('New slope: ', get_slope(bus, dev_address))
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def write_nvm(bus, dev_address):
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print('Writing to non-volatile memory')
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EEPROMControl = [0]*8
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EEPROMControl[2] = 1 # EE_INIT=1
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write_reg(bus, dev_address, 'EEPROMControl', EEPROMControl)
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EEPROMControl[1] = 1 # EE_PROG=1
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EEPROMControl[2] = 0 # EE_INIT=0
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write_reg(bus, dev_address, 'EEPROMControl', EEPROMControl)
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time.sleep(0.2) # wait 200ms
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EEPROMControl[1] = 0 # EE_PROG=0
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write_reg(bus, dev_address, 'EEPROMControl', EEPROMControl)
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def load_nvm(bus, dev_address):
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print('Loading from non-volatile memory')
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EEPROMControl = [0]*8
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EEPROMControl[2] = 1 # EE_INIT=1
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write_reg(bus, dev_address, 'EEPROMControl', EEPROMControl)
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EEPROMControl[0] = 1 # EE_READ=1
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EEPROMControl[2] = 0 # EE_INIT=0
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write_reg(bus, dev_address, 'EEPROMControl', EEPROMControl)
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time.sleep(0.2) # wait 200ms
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EEPROMControl[0] = 0 # EE_READ=0
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write_reg(bus, dev_address, 'EEPROMControl', EEPROMControl)
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def main():
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bus = smbus2.SMBus(config['smbus_address'])
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set_slope(bus, config['device_address'], config['slope'])
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write_nvm(bus, config['device_address'])
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load_nvm(bus, config['device_address'])
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print('Slope in non-volatile memory: ', get_slope(bus,config['device_address']))
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if __name__ == "__main__":
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main()
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