69c8c0c0ef
This driver assumes that an interrupt line is always available for the I2C master. This is not always the case and this patch adds support for a polling version. Report from Andrew Lunn: I did some timing tests for this. On my box, we request a udelay of 80uS. The kernel actually delays for about 79uS. We then spin in ocores_wait() for an additional 10-11uS, which is 3 to 4 iterations. There are actually 9 bits on the wire, not 8, since there is an ACK/NACK bit after the actual data transfer. So i changed the delay to (9 * 1000) / i2c->bus_clock_khz. That resulted in ocores_wait() mostly not looping at all. But for reading an 4K AT24 EEPROM, it increased the read time by 10ms, from 424ms to 434ms. So we should probably keep with 8. Signed-off-by: Federico Vaga <federico.vaga@cern.ch> Tested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.