| This is an explanation of what i2c is, and what is supported in this package. | |
| I2C and SMBus | |
| ============= | |
| I2C (pronounce: I squared C) is a protocol developed by Philips. It is a | |
| slow two-wire protocol (10-400 kHz), but it suffices for many types of | |
| devices. | |
| SMBus (System Management Bus) is a subset of the I2C protocol. Many | |
| modern mainboards have a System Management Bus. There are a lot of | |
| devices which can be connected to a SMBus; the most notable are modern | |
| memory chips with EEPROM memories and chips for hardware monitoring. | |
| Because the SMBus is just a special case of the generalized I2C bus, we | |
| can simulate the SMBus protocol on plain I2C busses. The reverse is | |
| regretfully impossible. | |
| Terminology | |
| =========== | |
| When we talk about I2C, we use the following terms: | |
| Bus -> Algorithm | |
| Adapter | |
| Device -> Driver | |
| Client | |
| An Algorithm driver contains general code that can be used for a whole class | |
| of I2C adapters. Each specific adapter driver depends on one algorithm | |
| driver. | |
| A Driver driver (yes, this sounds ridiculous, sorry) contains the general | |
| code to access some type of device. Each detected device gets its own | |
| data in the Client structure. Usually, Driver and Client are more closely | |
| integrated than Algorithm and Adapter. | |
| For a given configuration, you will need a driver for your I2C bus (usually | |
| a separate Adapter and Algorithm driver), and drivers for your I2C devices | |
| (usually one driver for each device). There are no I2C device drivers | |
| in this package. See the lm_sensors project http://www.lm-sensors.nu | |
| for device drivers. | |
| Included Bus Drivers | |
| ==================== | |
| Note that only stable drivers are patched into the kernel by 'mkpatch'. | |
| Base modules | |
| ------------ | |
| i2c-core: The basic I2C code, including the /proc/bus/i2c* interface | |
| i2c-dev: The /dev/i2c-* interface | |
| i2c-proc: The /proc/sys/dev/sensors interface for device (client) drivers | |
| Algorithm drivers | |
| ----------------- | |
| i2c-algo-8xx: An algorithm for CPM's I2C device in Motorola 8xx processors (NOT BUILT BY DEFAULT) | |
| i2c-algo-bit: A bit-banging algorithm | |
| i2c-algo-pcf: A PCF 8584 style algorithm | |
| i2c-algo-ibm_ocp: An algorithm for the I2C device in IBM 4xx processors (NOT BUILT BY DEFAULT) | |
| Adapter drivers | |
| --------------- | |
| i2c-elektor: Elektor ISA card (uses i2c-algo-pcf) | |
| i2c-elv: ELV parallel port adapter (uses i2c-algo-bit) | |
| i2c-pcf-epp: PCF8584 on a EPP parallel port (uses i2c-algo-pcf) (NOT mkpatched) | |
| i2c-philips-par: Philips style parallel port adapter (uses i2c-algo-bit) | |
| i2c-adap-ibm_ocp: IBM 4xx processor I2C device (uses i2c-algo-ibm_ocp) (NOT BUILT BY DEFAULT) | |
| i2c-pport: Primitive parallel port adapter (uses i2c-algo-bit) | |
| i2c-rpx: RPX board Motorola 8xx I2C device (uses i2c-algo-8xx) (NOT BUILT BY DEFAULT) | |
| i2c-velleman: Velleman K8000 parallel port adapter (uses i2c-algo-bit) | |