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1Kernel driver lm772==================3 4Supported chips:5 6 * National Semiconductor LM777 8 Prefix: 'lm77'9 10 Addresses scanned: I2C 0x48 - 0x4b11 12 Datasheet: Publicly available at the National Semiconductor website13 14 http://www.national.com/15 16 17Author: Andras BALI <drewie@freemail.hu>18 19Description20-----------21 22The LM77 implements one temperature sensor. The temperature23sensor incorporates a band-gap type temperature sensor,2410-bit ADC, and a digital comparator with user-programmable upper25and lower limit values.26 27The LM77 implements 3 limits: low (temp1_min), high (temp1_max) and28critical (temp1_crit.) It also implements an hysteresis mechanism which29applies to all 3 limits. The relative difference is stored in a single30register on the chip, which means that the relative difference between31the limit and its hysteresis is always the same for all 3 limits.32 33This implementation detail implies the following:34 35* When setting a limit, its hysteresis will automatically follow, the36 difference staying unchanged. For example, if the old critical limit37 was 80 degrees C, and the hysteresis was 75 degrees C, and you change38 the critical limit to 90 degrees C, then the hysteresis will39 automatically change to 85 degrees C.40* All 3 hysteresis can't be set independently. We decided to make41 temp1_crit_hyst writable, while temp1_min_hyst and temp1_max_hyst are42 read-only. Setting temp1_crit_hyst writes the difference between43 temp1_crit_hyst and temp1_crit into the chip, and the same relative44 hysteresis applies automatically to the low and high limits.45* The limits should be set before the hysteresis.46