| BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 1 | Kernel driver max6875 |
| 2 | ===================== |
| 3 | |
| 4 | Supported chips: |
| Jean Delvare | 089bd86 | 2005-06-23 23:37:53 +0200 | [diff] [blame^] | 5 | * Maxim MAX6874, MAX6875 |
| 6 | Prefix: 'max6875' |
| BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 7 | Addresses scanned: 0x50, 0x52 |
| Jean Delvare | 089bd86 | 2005-06-23 23:37:53 +0200 | [diff] [blame^] | 8 | Datasheet: |
| BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 9 | http://pdfserv.maxim-ic.com/en/ds/MAX6874-MAX6875.pdf |
| 10 | |
| 11 | Author: Ben Gardner <bgardner@wabtec.com> |
| 12 | |
| 13 | |
| 14 | Module Parameters |
| 15 | ----------------- |
| 16 | |
| 17 | * allow_write int |
| 18 | Set to non-zero to enable write permission: |
| 19 | *0: Read only |
| 20 | 1: Read and write |
| 21 | |
| 22 | |
| 23 | Description |
| 24 | ----------- |
| 25 | |
| Jean Delvare | 089bd86 | 2005-06-23 23:37:53 +0200 | [diff] [blame^] | 26 | The Maxim MAX6875 is an EEPROM-programmable power-supply sequencer/supervisor. |
| BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 27 | It provides timed outputs that can be used as a watchdog, if properly wired. |
| 28 | It also provides 512 bytes of user EEPROM. |
| 29 | |
| Jean Delvare | 089bd86 | 2005-06-23 23:37:53 +0200 | [diff] [blame^] | 30 | At reset, the MAX6875 reads the configuration EEPROM into its configuration |
| BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 31 | registers. The chip then begins to operate according to the values in the |
| 32 | registers. |
| 33 | |
| Jean Delvare | 089bd86 | 2005-06-23 23:37:53 +0200 | [diff] [blame^] | 34 | The Maxim MAX6874 is a similar, mostly compatible device, with more intputs |
| 35 | and outputs: |
| 36 | |
| 37 | vin gpi vout |
| 38 | MAX6874 6 4 8 |
| 39 | MAX6875 4 3 5 |
| 40 | |
| 41 | MAX6874 chips can have four different addresses (as opposed to only two for |
| 42 | the MAX6875). The additional addresses (0x54 and 0x56) are not probed by |
| 43 | this driver by default, but the probe module parameter can be used if |
| 44 | needed. |
| 45 | |
| BGardner@Wabtec.com | c3bc4ca | 2005-06-03 13:03:27 -0400 | [diff] [blame] | 46 | See the datasheet for details on how to program the EEPROM. |
| 47 | |
| 48 | |
| 49 | Sysfs entries |
| 50 | ------------- |
| 51 | |
| 52 | eeprom_user - 512 bytes of user-defined EEPROM space. Only writable if |
| 53 | allow_write was set and register 0x43 is 0. |
| 54 | |
| 55 | eeprom_config - 70 bytes of config EEPROM. Note that changes will not get |
| 56 | loaded into register space until a power cycle or device reset. |
| 57 | |
| 58 | reg_config - 70 bytes of register space. Any changes take affect immediately. |
| 59 | |
| 60 | |
| 61 | General Remarks |
| 62 | --------------- |
| 63 | |
| 64 | A typical application will require that the EEPROMs be programmed once and |
| 65 | never altered afterwards. |
| 66 | |