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author | Linus Torvalds <torvalds@linux-foundation.org> | 2011-03-16 19:05:40 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-03-16 19:05:40 -0700 |
commit | 63a93699c6a58795b854ff573542a08367684dae (patch) | |
tree | 057ab4cbde66862c51867dde030be69a2fa7073f /Documentation/arm/Sharp-LH/ADC-LH7-Touchscreen | |
parent | 16d8775700f1815076f879719ce14b33f50a3171 (diff) | |
parent | 21bd6d37cf23e643020bf28b41844ff0040c9393 (diff) | |
download | op-kernel-dev-63a93699c6a58795b854ff573542a08367684dae.zip op-kernel-dev-63a93699c6a58795b854ff573542a08367684dae.tar.gz |
Merge branch 'remove' of master.kernel.org:/home/rmk/linux-2.6-arm
* 'remove' of master.kernel.org:/home/rmk/linux-2.6-arm:
ARM: 6629/2: aaec2000: remove support for mach-aaec2000
ARM: lh7a40x: remove unmaintained platform support
Fix up trivial conflicts in
- arch/arm/mach-{aaec2000,lh7a40x}/include/mach/memory.h (removed)
- drivers/usb/gadget/Kconfig (USB_[GADGET_]LH7A40X removed, others added)
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 dc460f0..0000000 --- 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. |