| Kyle Swenson | 8d8f654 | 2021-03-15 11:02:55 -0600 | [diff] [blame] | 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 <linux@roeck-us.net> |
| 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. |