Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 36 insertions, 0 deletions

diff --git a/Documentation/spi/spi-sc18is602 b/Documentation/spi/spi-sc18is602
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+++ b/Documentation/spi/spi-sc18is602
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+Kernel driver spi-sc18is602
+===========================
+
+Supported chips:
+  * NXP SI18IS602/602B/603
+    Datasheet: http://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 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.