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-Kernel driver max6875
-=====================
-
-Supported chips:
- * Maxim MAX6874, MAX6875
- Prefix: 'max6875'
- Addresses scanned: None (see below)
- Datasheet:
- http://pdfserv.maxim-ic.com/en/ds/MAX6874-MAX6875.pdf
-
-Author: Ben Gardner <bgardner@wabtec.com>
-
-
-Description
------------
-
-The Maxim MAX6875 is an EEPROM-programmable power-supply sequencer/supervisor.
-It provides timed outputs that can be used as a watchdog, if properly wired.
-It also provides 512 bytes of user EEPROM.
-
-At reset, the MAX6875 reads the configuration EEPROM into its configuration
-registers. The chip then begins to operate according to the values in the
-registers.
-
-The Maxim MAX6874 is a similar, mostly compatible device, with more intputs
-and outputs:
- vin gpi vout
-MAX6874 6 4 8
-MAX6875 4 3 5
-
-See the datasheet for more information.
-
-
-Sysfs entries
--------------
-
-eeprom - 512 bytes of user-defined EEPROM space.
-
-
-General Remarks
----------------
-
-Valid addresses for the MAX6875 are 0x50 and 0x52.
-Valid addresses for the MAX6874 are 0x50, 0x52, 0x54 and 0x56.
-The driver does not probe any address, so you explicitly instantiate the
-devices.
-
-Example:
-$ modprobe max6875
-$ echo max6875 0x50 > /sys/bus/i2c/devices/i2c-0/new_device
-
-The MAX6874/MAX6875 ignores address bit 0, so this driver attaches to multiple
-addresses. For example, for address 0x50, it also reserves 0x51.
-The even-address instance is called 'max6875', the odd one is 'dummy'.
-
-
-Programming the chip using i2c-dev
-----------------------------------
-
-Use the i2c-dev interface to access and program the chips.
-Reads and writes are performed differently depending on the address range.
-
-The configuration registers are at addresses 0x00 - 0x45.
-Use i2c_smbus_write_byte_data() to write a register and
-i2c_smbus_read_byte_data() to read a register.
-The command is the register number.
-
-Examples:
-To write a 1 to register 0x45:
- i2c_smbus_write_byte_data(fd, 0x45, 1);
-
-To read register 0x45:
- value = i2c_smbus_read_byte_data(fd, 0x45);
-
-
-The configuration EEPROM is at addresses 0x8000 - 0x8045.
-The user EEPROM is at addresses 0x8100 - 0x82ff.
-
-Use i2c_smbus_write_word_data() to write a byte to EEPROM.
-
-The command is the upper byte of the address: 0x80, 0x81, or 0x82.
-The data word is the lower part of the address or'd with data << 8.
- cmd = address >> 8;
- val = (address & 0xff) | (data << 8);
-
-Example:
-To write 0x5a to address 0x8003:
- i2c_smbus_write_word_data(fd, 0x80, 0x5a03);
-
-
-Reading data from the EEPROM is a little more complicated.
-Use i2c_smbus_write_byte_data() to set the read address and then
-i2c_smbus_read_byte() or i2c_smbus_read_i2c_block_data() to read the data.
-
-Example:
-To read data starting at offset 0x8100, first set the address:
- i2c_smbus_write_byte_data(fd, 0x81, 0x00);
-
-And then read the data
- value = i2c_smbus_read_byte(fd);
-
- or
-
- count = i2c_smbus_read_i2c_block_data(fd, 0x84, 16, buffer);
-
-The block read should read 16 bytes.
-0x84 is the block read command.
-
-See the datasheet for more details.
-