[FE training-materials-updates] kernel-device-model: more improvements
Thomas Petazzoni
thomas.petazzoni at free-electrons.com
Fri Sep 27 16:27:32 CEST 2013
Repository : git://git.free-electrons.com/training-materials.git
On branch : kernel-ng
Link : http://git.free-electrons.com/training-materials/commit/?id=2c3be0e46f96415d9ac5d19b1f14e7e69225d2e8
>---------------------------------------------------------------
commit 2c3be0e46f96415d9ac5d19b1f14e7e69225d2e8
Author: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
Date: Fri Sep 27 16:27:08 2013 +0200
kernel-device-model: more improvements
Signed-off-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
>---------------------------------------------------------------
2c3be0e46f96415d9ac5d19b1f14e7e69225d2e8
slides/kernel-device-model/kernel-device-model.tex | 27 ++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/slides/kernel-device-model/kernel-device-model.tex b/slides/kernel-device-model/kernel-device-model.tex
index dfa0f40..a47ba96 100644
--- a/slides/kernel-device-model/kernel-device-model.tex
+++ b/slides/kernel-device-model/kernel-device-model.tex
@@ -553,6 +553,7 @@ static int serial_imx_probe(struct platform_device *pdev)
\item At boot time, the kernel is given a compiled version, the {\bf
Device Tree Blob}, which is parsed to instantiate all the
devices described in the DT.
+ \item On ARM, they are located in \code{arch/arm/boot/dts}.
\end{itemize}
\end{frame}
@@ -631,12 +632,38 @@ static struct platform_driver serial_omap_driver = {
\end{itemize}
\end{frame}
+\begin{frame}{Device Tree bindings}
+ \begin{itemize}
+ \item The compatible string and the associated properties define
+ what is called a {\em device tree binding}.
+ \item {\em Device tree bindings} are all documented in
+ \kerneldoc{devicetree/bindings}.
+ \item Since the Device Tree is normally part of the kernel ABI, the
+ {\em bindings} must remain compatible over-time.
+ \begin{itemize}
+ \item A new kernel must be capable of using an old Device Tree.
+ \item This requires a very careful design of the bindings. They
+ are all reviewed on the \code{devicetree at vger.kernel.org}
+ mailing list.
+ \end{itemize}
+ \item A Device Tree binding should contain only a {\em description
+ of the hardware} and not {\em configuration}.
+ \begin{itemize}
+ \item An interrupt number can be part of the Device Tree as it
+ describes the hardware.
+ \item But whether or not DMA should be used for a device, as it is
+ a configuration choice.
+ \end{itemize}
+ \end{itemize}
+\end{frame}
+
\begin{frame}
\frametitle{References}
\begin{itemize}
\item Kernel documentation
\begin{itemize}
\item \kerneldoc{driver-model/}
+ \item \kerneldoc{devicetree/}
\item \kerneldoc{filesystems/sysfs.txt}
\end{itemize}
\item The kernel source code
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