kernel_optimize_test/Documentation/spi/spi-sc18is602.rst
Alexander A. Klimov 3ea4eac3e2
SPI SUBSYSTEM: Replace HTTP links with HTTPS ones
Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.

Deterministic algorithm:
For each file:
  If not .svg:
    For each line:
      If doesn't contain `\bxmlns\b`:
        For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`:
	  If neither `\bgnu\.org/license`, nor `\bmozilla\.org/MPL\b`:
            If both the HTTP and HTTPS versions
            return 200 OK and serve the same content:
              Replace HTTP with HTTPS.

Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Link: https://lore.kernel.org/r/20200708194400.22213-1-grandmaster@al2klimov.de
Signed-off-by: Mark Brown <broonie@kernel.org>
2020-07-09 22:41:11 +01:00

40 lines
1.3 KiB
ReStructuredText

===========================
Kernel driver spi-sc18is602
===========================
Supported chips:
* NXP SI18IS602/602B/603
Datasheet: https://www.nxp.com/documents/data_sheet/SC18IS602_602B_603.pdf
Author:
Guenter Roeck <linux@roeck-us.net>
Description
-----------
This driver provides connects a NXP SC18IS602/603 I2C-bus to SPI bridge to the
kernel's SPI core subsystem.
The driver does not probe for supported chips, since the SI18IS602/603 does not
support Chip ID registers. You will have to instantiate the devices explicitly.
Please see Documentation/i2c/instantiating-devices.rst for details.
Usage Notes
-----------
This driver requires the I2C adapter driver to support raw I2C messages. I2C
adapter drivers which can only handle the SMBus protocol are not supported.
The maximum SPI message size supported by SC18IS602/603 is 200 bytes. Attempts
to initiate longer transfers will fail with -EINVAL. EEPROM read operations and
similar large accesses have to be split into multiple chunks of no more than
200 bytes per SPI message (128 bytes of data per message is recommended). This
means that programs such as "cp" or "od", which automatically use large block
sizes to access a device, can not be used directly to read data from EEPROM.
Programs such as dd, where the block size can be specified, should be used
instead.