| xj | b04a402 | 2021-11-25 15:01:52 +0800 | [diff] [blame] | 1 | What: /sys/bus/iio/devices/iio:deviceX/in_proximity0_agc_gain |
| 2 | What: /sys/bus/iio/devices/iio:deviceX/in_proximity0_agc_gain_bias |
| 3 | KernelVersion: 4.18 |
| 4 | Contact: linux-iio@vger.kernel.org |
| 5 | Description: |
| 6 | This sensor has an automatic gain control (agc) loop |
| 7 | which sets the analog signal levels at an optimum |
| 8 | level by controlling programmable gain amplifiers. The |
| 9 | criteria for optimal gain is determined by the sensor. |
| 10 | |
| 11 | Return the actual gain value as an integer in [0; 65536] |
| 12 | range when read from. |
| 13 | |
| 14 | The agc gain read when measuring crosstalk shall be |
| 15 | written into in_proximity0_agc_gain_bias. |
| 16 | |
| 17 | What: /sys/bus/iio/devices/iio:deviceX/in_proximity0_calib_phase_temp_a |
| 18 | What: /sys/bus/iio/devices/iio:deviceX/in_proximity0_calib_phase_temp_b |
| 19 | What: /sys/bus/iio/devices/iio:deviceX/in_proximity0_calib_phase_light_a |
| 20 | What: /sys/bus/iio/devices/iio:deviceX/in_proximity0_calib_phase_light_b |
| 21 | KernelVersion: 4.18 |
| 22 | Contact: linux-iio@vger.kernel.org |
| 23 | Description: |
| 24 | The sensor is able to perform correction of distance |
| 25 | measurements due to changing temperature and ambient |
| 26 | light conditions. It can be programmed to correct for |
| 27 | a second order error polynomial. |
| 28 | |
| 29 | Phase data has to be collected when temperature and |
| 30 | ambient light are modulated independently. |
| 31 | |
| 32 | Then a least squares curve fit to a second order |
| 33 | polynomial has to be generated from the data. The |
| 34 | resultant curves have the form ax^2 + bx + c. |
| 35 | |
| 36 | From those two curves, a and b coefficients shall be |
| 37 | stored in in_proximity0_calib_phase_temp_a and |
| 38 | in_proximity0_calib_phase_temp_b for temperature and |
| 39 | in in_proximity0_calib_phase_light_a and |
| 40 | in_proximity0_calib_phase_light_b for ambient light. |
| 41 | |
| 42 | Those values must be integer in [0; 8355840] range. |
| 43 | |
| 44 | Finally, the c constant is set by the sensor |
| 45 | internally. |
| 46 | |
| 47 | The value stored in sensor is displayed when read from. |