1 files changed, 116 insertions, 0 deletions

diff --git a/Documentation/misc-devices/bh1770glc.txt b/Documentation/misc-devices/bh1770glc.txt
new file mode 100644
index 000000000000..7d64c014dc70
--- /dev/null
+++ b/Documentation/misc-devices/bh1770glc.txt
@@ -0,0 +1,116 @@
+Kernel driver bh1770glc
+=======================
+
+Supported chips:
+ROHM BH1770GLC
+OSRAM SFH7770
+
+Data sheet:
+Not freely available
+
+Author:
+Samu Onkalo <samu.p.onkalo@nokia.com>
+
+Description
+-----------
+BH1770GLC and SFH7770 are combined ambient light and proximity sensors.
+ALS and proximity parts operates on their own, but they shares common I2C
+interface and interrupt logic. In principle they can run on their own,
+but ALS side results are used to estimate reliability of the proximity sensor.
+
+ALS produces 16 bit lux values. The chip contains interrupt logic to produce
+low and high threshold interrupts.
+
+Proximity part contains IR-led driver up to 3 IR leds. The chip measures
+amount of reflected IR light and produces proximity result. Resolution is
+8 bit. Driver supports only one channel. Driver uses ALS results to estimate
+reliability of the proximity results. Thus ALS is always running while
+proximity detection is needed.
+
+Driver uses threshold interrupts to avoid need for polling the values.
+Proximity low interrupt doesn't exists in the chip. This is simulated
+by using a delayed work. As long as there is proximity threshold above
+interrupts the delayed work is pushed forward. So, when proximity level goes
+below the threshold value, there is no interrupt and the delayed work will
+finally run. This is handled as no proximity indication.
+
+Chip state is controlled via runtime pm framework when enabled in config.
+
+Calibscale factor is used to hide differences between the chips. By default
+value set to neutral state meaning factor of 1.00. To get proper values,
+calibrated source of light is needed as a reference. Calibscale factor is set
+so that measurement produces about the expected lux value.
+
+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
+
+lux0_rate
+        RW - measurement rate in Hz
+
+lux0_rate_avail
+        RO - supported measurement rates
+
+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.
+
+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
+
+prox0_raw
+        RO - measured proximity value
+             sysfs_notify called when threshold interrupt occurs
+
+prox0_sensor_range
+        RO - prox0_raw max value
+
+prox0_raw_en
+        RW - enable / disable proximity - uses counting logic
+             1 enables the proximity
+             0 disables the proximity
+
+prox0_thresh_above_count
+        RW - number of proximity interrupts needed before triggering the event
+
+prox0_rate_above
+        RW - Measurement rate (in Hz) when the level is above threshold
+             i.e. when proximity on has been reported.
+
+prox0_rate_below
+        RW - Measurement rate (in Hz) when the level is below threshold
+             i.e. when proximity off has been reported.
+
+prox0_rate_avail
+        RO - Supported proximity measurement rates in Hz
+
+prox0_thresh_above0_value
+        RW - threshold level which trigs proximity events.
+             Filtered by persistence filter (prox0_thresh_above_count)
+
+prox0_thresh_above1_value
+        RW - threshold level which trigs event immediately