diff options
| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2011-01-21 11:04:45 +0000 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2011-01-24 19:05:19 +0000 |
| commit | 82e6923e1862428b755ec306b3dbccf926849314 (patch) | |
| tree | e0be095c30c7cbfeff2a2096cf53e9c2f92fed13 /Documentation/arm/Sharp-LH/ADC-LH7-Touchscreen | |
| parent | 1bae4ce27c9c90344f23c65ea6966c50ffeae2f5 (diff) | |
ARM: lh7a40x: remove unmaintained platform support
lh7a40x has only been receiving updates for updates to generic code.
The last involvement from the maintainer according to the git logs was
in 2006. As such, it is a maintainence burden with no benefit.
This gets rid of two defconfigs.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'Documentation/arm/Sharp-LH/ADC-LH7-Touchscreen')
| -rw-r--r-- | Documentation/arm/Sharp-LH/ADC-LH7-Touchscreen | 61 |
1 files changed, 0 insertions, 61 deletions
diff --git a/Documentation/arm/Sharp-LH/ADC-LH7-Touchscreen b/Documentation/arm/Sharp-LH/ADC-LH7-Touchscreen deleted file mode 100644 index dc460f05564..00000000000 --- a/Documentation/arm/Sharp-LH/ADC-LH7-Touchscreen +++ /dev/null @@ -1,61 +0,0 @@ -README on the ADC/Touchscreen Controller -======================================== - -The LH79524 and LH7A404 include a built-in Analog to Digital -controller (ADC) that is used to process input from a touchscreen. -The driver only implements a four-wire touch panel protocol. - -The touchscreen driver is maintenance free except for the pen-down or -touch threshold. Some resistive displays and board combinations may -require tuning of this threshold. The driver exposes some of its -internal state in the sys filesystem. If the kernel is configured -with it, CONFIG_SYSFS, and sysfs is mounted at /sys, there will be a -directory - - /sys/devices/platform/adc-lh7.0 - -containing these files. - - -r--r--r-- 1 root root 4096 Jan 1 00:00 samples - -rw-r--r-- 1 root root 4096 Jan 1 00:00 threshold - -r--r--r-- 1 root root 4096 Jan 1 00:00 threshold_range - -The threshold is the current touch threshold. It defaults to 750 on -most targets. - - # cat threshold - 750 - -The threshold_range contains the range of valid values for the -threshold. Values outside of this range will be silently ignored. - - # cat threshold_range - 0 1023 - -To change the threshold, write a value to the threshold file. - - # echo 500 > threshold - # cat threshold - 500 - -The samples file contains the most recently sampled values from the -ADC. There are 12. Below are typical of the last sampled values when -the pen has been released. The first two and last two samples are for -detecting whether or not the pen is down. The third through sixth are -X coordinate samples. The seventh through tenth are Y coordinate -samples. - - # cat samples - 1023 1023 0 0 0 0 530 529 530 529 1023 1023 - -To determine a reasonable threshold, press on the touch panel with an -appropriate stylus and read the values from samples. - - # cat samples - 1023 676 92 103 101 102 855 919 922 922 1023 679 - -The first and eleventh samples are discarded. Thus, the important -values are the second and twelfth which are used to determine if the -pen is down. When both are below the threshold, the driver registers -that the pen is down. When either is above the threshold, it -registers then pen is up. |