diff options
author | Yunhong Jiang <yunhong.jiang@intel.com> | 2015-08-04 12:17:53 -0700 |
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committer | Yunhong Jiang <yunhong.jiang@intel.com> | 2015-08-04 15:44:42 -0700 |
commit | 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch) | |
tree | 1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/Documentation/misc-devices/apds990x.txt | |
parent | 98260f3884f4a202f9ca5eabed40b1354c489b29 (diff) |
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base.
It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:
commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Sat Jul 25 12:13:34 2015 +0200
Prepare v4.1.3-rt3
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.
Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/Documentation/misc-devices/apds990x.txt')
-rw-r--r-- | kernel/Documentation/misc-devices/apds990x.txt | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/kernel/Documentation/misc-devices/apds990x.txt b/kernel/Documentation/misc-devices/apds990x.txt new file mode 100644 index 000000000..d5408cade --- /dev/null +++ b/kernel/Documentation/misc-devices/apds990x.txt @@ -0,0 +1,111 @@ +Kernel driver apds990x +====================== + +Supported chips: +Avago APDS990X + +Data sheet: +Not freely available + +Author: +Samu Onkalo <samu.p.onkalo@nokia.com> + +Description +----------- + +APDS990x is a combined ambient light and proximity sensor. ALS and proximity +functionality are highly connected. ALS measurement path must be running +while the proximity functionality is enabled. + +ALS produces raw measurement values for two channels: Clear channel +(infrared + visible light) and IR only. However, threshold comparisons happen +using clear channel only. Lux value and the threshold level on the HW +might vary quite much depending the spectrum of the light source. + +Driver makes necessary conversions to both directions so that user handles +only lux values. Lux value is calculated using information from the both +channels. HW threshold level is calculated from the given lux value to match +with current type of the lightning. Sometimes inaccuracy of the estimations +lead to false interrupt, but that doesn't harm. + +ALS contains 4 different gain steps. Driver automatically +selects suitable gain step. After each measurement, reliability of the results +is estimated and new measurement is trigged if necessary. + +Platform data can provide tuned values to the conversion formulas if +values are known. Otherwise plain sensor default values are used. + +Proximity side is little bit simpler. There is no need for complex conversions. +It produces directly usable values. + +Driver controls chip operational state using pm_runtime framework. +Voltage regulators are controlled based on chip operational state. + +SYSFS +----- + + +chip_id + RO - shows detected chip type and version + +power_state + RW - enable / disable chip. Uses counting logic + 1 enables the chip + 0 disables the chip +lux0_input + RO - measured lux value + sysfs_notify called when threshold interrupt occurs + +lux0_sensor_range + RO - lux0_input max value. Actually never reaches since sensor tends + to saturate much before that. Real max value varies depending + on the light spectrum etc. + +lux0_rate + RW - measurement rate in Hz + +lux0_rate_avail + RO - supported measurement rates + +lux0_calibscale + RW - calibration value. Set to neutral value by default. + Output results are multiplied with calibscale / calibscale_default + value. + +lux0_calibscale_default + RO - neutral calibration value + +lux0_thresh_above_value + RW - HI level threshold value. All results above the value + trigs an interrupt. 65535 (i.e. sensor_range) disables the above + interrupt. + +lux0_thresh_below_value + RW - LO level threshold value. All results below the value + trigs an interrupt. 0 disables the below interrupt. + +prox0_raw + RO - measured proximity value + sysfs_notify called when threshold interrupt occurs + +prox0_sensor_range + RO - prox0_raw max value (1023) + +prox0_raw_en + RW - enable / disable proximity - uses counting logic + 1 enables the proximity + 0 disables the proximity + +prox0_reporting_mode + RW - trigger / periodic. In "trigger" mode the driver tells two possible + values: 0 or prox0_sensor_range value. 0 means no proximity, + 1023 means proximity. This causes minimal number of interrupts. + In "periodic" mode the driver reports all values above + prox0_thresh_above. This causes more interrupts, but it can give + _rough_ estimate about the distance. + +prox0_reporting_mode_avail + RO - accepted values to prox0_reporting_mode (trigger, periodic) + +prox0_thresh_above_value + RW - threshold level which trigs proximity events. |