mainlining shenanigans
feda284004
This patch adds support for the ultrasonic ranger srf04 of devantech.
This device is measuring the distance of objects in a range between 1 cm
and 3 meters and a theoretical resolution of 3 mm.
There are two GPIOs used:
- trigger: set as output to the device when the measurement should start
- echo: set by the device when the ultrasonic wave is sent out and reset
when the echo is recognized; this needs to be an interrupt input
The time between setting and resetting the echo pin is the time the
waveform needed for one round trip. This time is recorded in the interrupt
handler.
The distance is calculated in the read function by using the ultrasonic
speed at 20 degrees celsius which is about 343 m/s.
Signed-off-by: Andreas Klinger <ak@it-klinger.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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| certs | ||
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| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. 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.