1Kernel driver pc87360 2===================== 3 4Supported chips: 5 * National Semiconductor PC87360, PC87363, PC87364, PC87365 and PC87366 6 Prefixes: 'pc87360', 'pc87363', 'pc87364', 'pc87365', 'pc87366' 7 Addresses scanned: none, address read from Super I/O config space 8 Datasheets: No longer available 9 10Authors: Jean Delvare <jdelvare@suse.de> 11 12Thanks to Sandeep Mehta, Tonko de Rooy and Daniel Ceregatti for testing. 13Thanks to Rudolf Marek for helping me investigate conversion issues. 14 15 16Module Parameters 17----------------- 18 19* init int 20 Chip initialization level: 21 0: None 22 *1: Forcibly enable internal voltage and temperature channels, except in9 23 2: Forcibly enable all voltage and temperature channels, except in9 24 3: Forcibly enable all voltage and temperature channels, including in9 25 26Note that this parameter has no effect for the PC87360, PC87363 and PC87364 27chips. 28 29Also note that for the PC87366, initialization levels 2 and 3 don't enable 30all temperature channels, because some of them share pins with each other, 31so they can't be used at the same time. 32 33 34Description 35----------- 36 37The National Semiconductor PC87360 Super I/O chip contains monitoring and 38PWM control circuitry for two fans. The PC87363 chip is similar, and the 39PC87364 chip has monitoring and PWM control for a third fan. 40 41The National Semiconductor PC87365 and PC87366 Super I/O chips are complete 42hardware monitoring chipsets, not only controlling and monitoring three fans, 43but also monitoring eleven voltage inputs and two (PC87365) or up to four 44(PC87366) temperatures. 45 46 Chip #vin #fan #pwm #temp devid 47 48 PC87360 - 2 2 - 0xE1 49 PC87363 - 2 2 - 0xE8 50 PC87364 - 3 3 - 0xE4 51 PC87365 11 3 3 2 0xE5 52 PC87366 11 3 3 3-4 0xE9 53 54The driver assumes that no more than one chip is present, and one of the 55standard Super I/O addresses is used (0x2E/0x2F or 0x4E/0x4F) 56 57Fan Monitoring 58-------------- 59 60Fan rotation speeds are reported in RPM (revolutions per minute). An alarm 61is triggered if the rotation speed has dropped below a programmable limit. 62A different alarm is triggered if the fan speed is too low to be measured. 63 64Fan readings are affected by a programmable clock divider, giving the 65readings more range or accuracy. Usually, users have to learn how it works, 66but this driver implements dynamic clock divider selection, so you don't 67have to care no more. 68 69For reference, here are a few values about clock dividers: 70 71 slowest accuracy highest 72 measurable around 3000 accurate 73 divider speed (RPM) RPM (RPM) speed (RPM) 74 1 1882 18 6928 75 2 941 37 4898 76 4 470 74 3464 77 8 235 150 2449 78 79For the curious, here is how the values above were computed: 80 * slowest measurable speed: clock/(255*divider) 81 * accuracy around 3000 RPM: 3000^2/clock 82 * highest accurate speed: sqrt(clock*100) 83The clock speed for the PC87360 family is 480 kHz. I arbitrarily chose 100 84RPM as the lowest acceptable accuracy. 85 86As mentioned above, you don't have to care about this no more. 87 88Note that not all RPM values can be represented, even when the best clock 89divider is selected. This is not only true for the measured speeds, but 90also for the programmable low limits, so don't be surprised if you try to 91set, say, fan1_min to 2900 and it finally reads 2909. 92 93 94Fan Control 95----------- 96 97PWM (pulse width modulation) values range from 0 to 255, with 0 meaning 98that the fan is stopped, and 255 meaning that the fan goes at full speed. 99 100Be extremely careful when changing PWM values. Low PWM values, even 101non-zero, can stop the fan, which may cause irreversible damage to your 102hardware if temperature increases too much. When changing PWM values, go 103step by step and keep an eye on temperatures. 104 105One user reported problems with PWM. Changing PWM values would break fan 106speed readings. No explanation nor fix could be found. 107 108 109Temperature Monitoring 110---------------------- 111 112Temperatures are reported in degrees Celsius. Each temperature measured has 113associated low, high and overtemperature limits, each of which triggers an 114alarm when crossed. 115 116The first two temperature channels are external. The third one (PC87366 117only) is internal. 118 119The PC87366 has three additional temperature channels, based on 120thermistors (as opposed to thermal diodes for the first three temperature 121channels). For technical reasons, these channels are held by the VLM 122(voltage level monitor) logical device, not the TMS (temperature 123measurement) one. As a consequence, these temperatures are exported as 124voltages, and converted into temperatures in user-space. 125 126Note that these three additional channels share their pins with the 127external thermal diode channels, so you (physically) can't use them all at 128the same time. Although it should be possible to mix the two sensor types, 129the documents from National Semiconductor suggest that motherboard 130manufacturers should choose one type and stick to it. So you will more 131likely have either channels 1 to 3 (thermal diodes) or 3 to 6 (internal 132thermal diode, and thermistors). 133 134 135Voltage Monitoring 136------------------ 137 138Voltages are reported relatively to a reference voltage, either internal or 139external. Some of them (in7:Vsb, in8:Vdd and in10:AVdd) are divided by two 140internally, you will have to compensate in sensors.conf. Others (in0 to in6) 141are likely to be divided externally. The meaning of each of these inputs as 142well as the values of the resistors used for division is left to the 143motherboard manufacturers, so you will have to document yourself and edit 144sensors.conf accordingly. National Semiconductor has a document with 145recommended resistor values for some voltages, but this still leaves much 146room for per motherboard specificities, unfortunately. Even worse, 147motherboard manufacturers don't seem to care about National Semiconductor's 148recommendations. 149 150Each voltage measured has associated low and high limits, each of which 151triggers an alarm when crossed. 152 153When available, VID inputs are used to provide the nominal CPU Core voltage. 154The driver will default to VRM 9.0, but this can be changed from user-space. 155The chipsets can handle two sets of VID inputs (on dual-CPU systems), but 156the driver will only export one for now. This may change later if there is 157a need. 158 159 160General Remarks 161--------------- 162 163If an alarm triggers, it will remain triggered until the hardware register 164is read at least once. This means that the cause for the alarm may already 165have disappeared! Note that all hardware registers are read whenever any 166data is read (unless it is less than 2 seconds since the last update, in 167which case cached values are returned instead). As a consequence, when 168a once-only alarm triggers, it may take 2 seconds for it to show, and 2 169more seconds for it to disappear. 170 171Monitoring of in9 isn't enabled at lower init levels (<3) because that 172channel measures the battery voltage (Vbat). It is a known fact that 173repeatedly sampling the battery voltage reduces its lifetime. National 174Semiconductor smartly designed their chipset so that in9 is sampled only 175once every 1024 sampling cycles (that is every 34 minutes at the default 176sampling rate), so the effect is attenuated, but still present. 177 178 179Limitations 180----------- 181 182The datasheets suggests that some values (fan mins, fan dividers) 183shouldn't be changed once the monitoring has started, but we ignore that 184recommendation. We'll reconsider if it actually causes trouble. 185