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1Kernel driver adm10262=====================3 4Supported chips:5 * Analog Devices ADM10266 7 Prefix: 'adm1026'8 9 Addresses scanned: I2C 0x2c, 0x2d, 0x2e10 11 Datasheet: Publicly available at the Analog Devices website12 13 https://www.onsemi.com/PowerSolutions/product.do?id=ADM102614 15Authors:16 - Philip Pokorny <ppokorny@penguincomputing.com> for Penguin Computing17 - Justin Thiessen <jthiessen@penguincomputing.com>18 19Module Parameters20-----------------21 22* gpio_input: int array (min = 1, max = 17)23 List of GPIO pins (0-16) to program as inputs24 25* gpio_output: int array (min = 1, max = 17)26 List of GPIO pins (0-16) to program as outputs27 28* gpio_inverted: int array (min = 1, max = 17)29 List of GPIO pins (0-16) to program as inverted30 31* gpio_normal: int array (min = 1, max = 17)32 List of GPIO pins (0-16) to program as normal/non-inverted33 34* gpio_fan: int array (min = 1, max = 8)35 List of GPIO pins (0-7) to program as fan tachs36 37 38Description39-----------40 41This driver implements support for the Analog Devices ADM1026. Analog42Devices calls it a "complete thermal system management controller."43 44The ADM1026 implements three (3) temperature sensors, 17 voltage sensors,4516 general purpose digital I/O lines, eight (8) fan speed sensors (8-bit),46an analog output and a PWM output along with limit, alarm and mask bits for47all of the above. There is even 8k bytes of EEPROM memory on chip.48 49Temperatures are measured in degrees Celsius. There are two external50sensor inputs and one internal sensor. Each sensor has a high and low51limit. If the limit is exceeded, an interrupt (#SMBALERT) can be52generated. The interrupts can be masked. In addition, there are over-temp53limits for each sensor. If this limit is exceeded, the #THERM output will54be asserted. The current temperature and limits have a resolution of 155degree.56 57Fan rotation speeds are reported in RPM (rotations per minute) but measured58in counts of a 22.5kHz internal clock. Each fan has a high limit which59corresponds to a minimum fan speed. If the limit is exceeded, an interrupt60can be generated. Each fan can be programmed to divide the reference clock61by 1, 2, 4 or 8. Not all RPM values can accurately be represented, so some62rounding is done. With a divider of 8, the slowest measurable speed of a63two pulse per revolution fan is 661 RPM.64 65There are 17 voltage sensors. An alarm is triggered if the voltage has66crossed a programmable minimum or maximum limit. Note that minimum in this67case always means 'closest to zero'; this is important for negative voltage68measurements. Several inputs have integrated attenuators so they can measure69higher voltages directly. 3.3V, 5V, 12V, -12V and battery voltage all have70dedicated inputs. There are several inputs scaled to 0-3V full-scale range71for SCSI terminator power. The remaining inputs are not scaled and have72a 0-2.5V full-scale range. A 2.5V or 1.82V reference voltage is provided73for negative voltage measurements.74 75If an alarm triggers, it will remain triggered until the hardware register76is read at least once. This means that the cause for the alarm may already77have disappeared! Note that in the current implementation, all hardware78registers are read whenever any data is read (unless it is less than 2.079seconds since the last update). This means that you can easily miss80once-only alarms.81 82The ADM1026 measures continuously. Analog inputs are measured about 483times a second. Fan speed measurement time depends on fan speed and84divisor. It can take as long as 1.5 seconds to measure all fan speeds.85 86The ADM1026 has the ability to automatically control fan speed based on the87temperature sensor inputs. Both the PWM output and the DAC output can be88used to control fan speed. Usually only one of these two outputs will be89used. Write the minimum PWM or DAC value to the appropriate control90register. Then set the low temperature limit in the tmin values for each91temperature sensor. The range of control is fixed at 20 °C, and the92largest difference between current and tmin of the temperature sensors sets93the control output. See the datasheet for several example circuits for94controlling fan speed with the PWM and DAC outputs. The fan speed sensors95do not have PWM compensation, so it is probably best to control the fan96voltage from the power lead rather than on the ground lead.97 98The datasheet shows an example application with VID signals attached to99GPIO lines. Unfortunately, the chip may not be connected to the VID lines100in this way. The driver assumes that the chips *is* connected this way to101get a VID voltage.102