[bootlin/training-materials updates] master: labs/kernel-i2c-communication: use msleep, not usleep_range (bbba4b37)
Thomas Petazzoni
thomas.petazzoni at bootlin.com
Tue Oct 13 17:53:44 CEST 2020
Repository : https://github.com/bootlin/training-materials
On branch : master
Link : https://github.com/bootlin/training-materials/commit/bbba4b3771b1d45ea5288b1eef4f732f41cc2e9b
>---------------------------------------------------------------
commit bbba4b3771b1d45ea5288b1eef4f732f41cc2e9b
Author: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
Date: Tue Oct 13 17:53:15 2020 +0200
labs/kernel-i2c-communication: use msleep, not usleep_range
usleep_range(10, 20) is not sufficient to sleep 10ms, switch back to
using msleep(10).
Signed-off-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
>---------------------------------------------------------------
bbba4b3771b1d45ea5288b1eef4f732f41cc2e9b
labs/kernel-i2c-communication/kernel-i2c-communication.tex | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)
diff --git a/labs/kernel-i2c-communication/kernel-i2c-communication.tex b/labs/kernel-i2c-communication/kernel-i2c-communication.tex
index 48883bba..386178d1 100644
--- a/labs/kernel-i2c-communication/kernel-i2c-communication.tex
+++ b/labs/kernel-i2c-communication/kernel-i2c-communication.tex
@@ -257,12 +257,7 @@ In this function:
\begin{enumerate}
\item Start by putting a \code{10 ms} delay by calling
- \code{usleep_range(10, 20)}, guaranteed to sleep between 10 and 20
- ms.\footnote{That's better than using \kfunc{udelay} because it is not making
- an active wait, and instead lets the CPU run other tasks in the meantime.
- You'll find interesting details on how to sleep or wait in kernel
- code for specified durations in the kernel documentation:
- \kerneldochtml{timers/timers-howto}.}
+ \code{msleep(10)}.
Such waiting time is needed to add time between the previous i2c
operation and the next one.
\item Write \code{0x00} to the bus. That will allow us to read
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