projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 3ce8859e GR |
1 | Kernel driver spi-sc18is602 |
| 2 | =========================== | |
| 3 | ||
| 4 | Supported chips: | |
| 5 | * NXP SI18IS602/602B/603 | |
| 6 | Datasheet: http://www.nxp.com/documents/data_sheet/SC18IS602_602B_603.pdf | |
| 7 | ||
| 8 | Author: | |
| 9 | Guenter Roeck <[email protected]> | |
| 10 | ||
| 11 | ||
| 12 | Description | |
| 13 | ----------- | |
| 14 | ||
| 15 | This driver provides connects a NXP SC18IS602/603 I2C-bus to SPI bridge to the | |
| 16 | kernel's SPI core subsystem. | |
| 17 | ||
| 18 | The driver does not probe for supported chips, since the SI18IS602/603 does not | |
| 19 | support Chip ID registers. You will have to instantiate the devices explicitly. | |
| 20 | Please see Documentation/i2c/instantiating-devices for details. | |
| 21 | ||
| 22 | ||
| 23 | Usage Notes | |
| 24 | ----------- | |
| 25 | ||
| 26 | This driver requires the I2C adapter driver to support raw I2C messages. I2C | |
| 27 | adapter drivers which can only handle the SMBus protocol are not supported. | |
| 28 | ||
| 29 | The maximum SPI message size supported by SC18IS602/603 is 200 bytes. Attempts | |
| 30 | to initiate longer transfers will fail with -EINVAL. EEPROM read operations and | |
| 31 | similar large accesses have to be split into multiple chunks of no more than | |
| 32 | 200 bytes per SPI message (128 bytes of data per message is recommended). This | |
| 33 | means that programs such as "cp" or "od", which automatically use large block | |
| 34 | sizes to access a device, can not be used directly to read data from EEPROM. | |
| 35 | Programs such as dd, where the block size can be specified, should be used | |
| 36 | instead. |