09c8192be7
The uSDHC supports DDR modes for eMMC devices running at 3.3V. This allows to run eMMC with 3.3V signaling voltage at DDR52 mode: # cat /sys/kernel/debug/mmc1/ios clock: 52000000 Hz vdd: 21 (3.3 ~ 3.4 V) bus mode: 2 (push-pull) chip select: 0 (don't care) power mode: 2 (on) bus width: 3 (8 bits) timing spec: 8 (mmc DDR52) signal voltage: 0 (3.30 V) driver type: 0 (driver type B) Signed-off-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.