[BL training-materials-updates] Kernel labs: cleaner way to modify the DTS

[Michael Opdenacker]

Repository : git://git.free-electrons.com/training-materials.git
On branch  : master
Link       : http://git.free-electrons.com/training-materials/commit/?id=5a6e9b4fb8ffe9e5db61af90357899ea2be4caff

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commit 5a6e9b4fb8ffe9e5db61af90357899ea2be4caff
Author: Michael Opdenacker <michael.opdenacker at free-electrons.com>
Date:   Sun May 27 16:09:15 2018 +0200

    Kernel labs: cleaner way to modify the DTS
    
    - We are now telling people to include the whole board DTS
      file and only add definitions or overrides.
    
    - With the previous instructions and the evolution of the
      BBB DTS files, you could have ended up missing important
      settings. Better include the full board DTS to make sure
      we're not missing anything!
    
    Signed-off-by: Michael Opdenacker <michael.opdenacker at free-electrons.com>


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5a6e9b4fb8ffe9e5db61af90357899ea2be4caff
 .../kernel-i2c-device-model/kernel-i2c-device-model.tex | 17 +++++++++--------
 labs/kernel-serial-iomem/kernel-serial-iomem.tex        |  6 +++---
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/labs/kernel-i2c-device-model/kernel-i2c-device-model.tex b/labs/kernel-i2c-device-model/kernel-i2c-device-model.tex
index 2020983..b630b92 100644
--- a/labs/kernel-i2c-device-model/kernel-i2c-device-model.tex
+++ b/labs/kernel-i2c-device-model/kernel-i2c-device-model.tex
@@ -64,14 +64,15 @@ description of this device in the board device tree.
 
 As the Beaglebone Black device tree is provided by the kernel community,
 and will continue to evolve on its own, we don't want to make changes
-directly to the device tree file for this board. The best solution is
-to create a custom device tree for your board with the new device.
-After all, it is like a custom board!
-
-So, reusing code from the Beaglebone Black DTS, create an
-\code{am335x-customboneblack.dts} file. At this stage, all you will
-need will be the DTS includes and the definitions of the \code{model}
-and \code{compatible} properties. All the rest can go away.
+directly to the device tree file for this board. 
+
+The easiest way to customize the board DTS is to create a new DTS file
+that includes the Beaglebone Black or Black Wireless DTS, and add
+its own definitions.
+
+So, create a new \code{am335x-customboneblack.dts} file in which you
+just include the regular board DTS file. We will add further definitions
+in the next sections.
 
 Now, modify the corresponding \code{Makefile} to make sure the
 new DTS is compiled automatically.
diff --git a/labs/kernel-serial-iomem/kernel-serial-iomem.tex b/labs/kernel-serial-iomem/kernel-serial-iomem.tex
index cf3db49..12cdeb0 100644
--- a/labs/kernel-serial-iomem/kernel-serial-iomem.tex
+++ b/labs/kernel-serial-iomem/kernel-serial-iomem.tex
@@ -48,9 +48,9 @@ You can (or even should) show your connections to the instructor
 to make sure that you haven't swapped the \code{RX} and \code{TX} pins.
 
 Now, create again a new
-\code{arch/arm/boot/dts/am335x-customboneblack.dts}
-file and create a pin muxing section with declarations for UART2 and
-UART4:
+\code{arch/arm/boot/dts/am335x-customboneblack.dts} file including
+the standard board DTS file and create a pin muxing section with
+declarations for UART2 and UART4:
 
 {\small \sourcecode{labs/kernel-serial-iomem/uarts-pinctrl.dts}}