lm75_get16
err = lm75_get16(arg, LM75_TEMPERATURE_REG, unitp, mode);
err = lm75_get16(arg, LM75_HYST_REG, unitp, mode);
err = lm75_get16(arg, LM75_OVERTEMP_REG, unitp, mode);
static int lm75_get16(intptr_t, int, struct lm75_unit *, int);