7  * Based on the lm83 driver. The LM90 is a sensor chip made by National
9  * one external one) with a 0.125 deg resolution (1 deg for local
10  * temperature) and a 3-4 deg accuracy.
22  * has a higher accuracy.
24  * This driver also supports the ADM1032, a sensor chip made by Analog
25  * Devices. That chip is similar to the LM90, with a few differences
26  * that are not handled by this driver. Among others, it has a higher
33  * in a detection as max6657 if it is on address 0x4c. The extra address
65  * and extended mode. They are mostly compatible with LM90 except for a data
735  * to explicitly ask for a transaction without PEC.
824 	 * For volatile registers we have to use a trick.  in lm90_read16()
826 	 * but we have to beware a conversion could occur between the  in lm90_read16()
833 	 * then we have a valid reading. Otherwise we have to read the low  in lm90_read16()
834 	 * byte again, and now we believe we have a correct reading.  in lm90_read16()
862  * in detection or initialization steps), and while a remote channel other
865  * various registers have different meanings as a result of selecting a
1773 	 * Repeat several times, each time checking against a different  in lm90_detect_lm84()
1785 		/* If any register has a different value, this is not an LM84 */  in lm90_detect_lm84()
1813 	 * A byte read operation repeats the most recent read operation  in lm90_detect_max1617()
1832 	 * A byte read operation repeats the most recent read and should  in lm90_detect_max1617()
1938 	 * for most of the chips, yet appear to return a well defined value.  in lm90_detect_analog()
1940 	 * is undocumented for all chips, but also returns a well defined value.  in lm90_detect_analog()
1948 	 * adm1020	00	00	00	41	39  in lm90_detect_analog()
1949 	 * adm1021	00	00	00	41	03  in lm90_detect_analog()
1950 	 * adm1021a	00	00	00	41	3c  in lm90_detect_analog()
1951 	 * adm1023	00	00	00	41	3c	same as adm1021a  in lm90_detect_analog()
1952 	 * adm1032	00	00	00	41	42  in lm90_detect_analog()
1954 	 * adt7421	21	41	04	41	04  in lm90_detect_analog()
1955 	 * adt7461	00	00	00	41	51  in lm90_detect_analog()
1956 	 * adt7461a	61	41	05	41	57  in lm90_detect_analog()
1957 	 * adt7481	81	41	02	41	62  in lm90_detect_analog()
1958 	 * adt7482	-	-	-	41	65	datasheet  in lm90_detect_analog()
1959 	 *		82	41	05	41	75	real chip  in lm90_detect_analog()
1960 	 * adt7483	83	41	04	41	94  in lm90_detect_analog()
1962 	 * nct72	61	41	07	41	55  in lm90_detect_analog()
1963 	 * nct210	00	00	00	41	3f  in lm90_detect_analog()
1964 	 * nct214	61	41	08	41	5a  in lm90_detect_analog()
1965 	 * nct1008	-	-	-	41	57	datasheet rev. 3  in lm90_detect_analog()
1966 	 *		61	41	06	41	54	real chip  in lm90_detect_analog()
1968 	 * nvt210	-	-	-	41	-	datasheet  in lm90_detect_analog()
1969 	 * nvt211	-	-	-	41	-	datasheet  in lm90_detect_analog()
1989 		 * found to have a Chip ID of 0x3c.  in lm90_detect_analog()
1991 		 * (0x12 .. 0x14), but a chip labeled ADM1021A does support it.  in lm90_detect_analog()
1995 		 * It is currently unknown if there is a means to distinguish  in lm90_detect_analog()
2109 		 * Even though MAX6695 and MAX6696 do not have a chip ID  in lm90_detect_maxim()
2138 		 * unsupported registers were observed to return a fixed value  in lm90_detect_maxim()
2141 		 * "MAX1617" (no "A") were observed to report manufacturer ID  in lm90_detect_maxim()
2166 		 * MAX6690 datasheet lists a chip ID of 0x08, and a chip labeled  in lm90_detect_maxim()
2167 		 * MAX6654 was observed to have a chip ID of 0x09.  in lm90_detect_maxim()
2174 		 * MAX6642, MAX6657, MAX6658 and MAX6659 do NOT have a chip_id  in lm90_detect_maxim()
2178 		 * MAX6642 does not have a conversion rate register, nor low  in lm90_detect_maxim()
2183 		 * a low nibble, so the value will be those of the previous  in lm90_detect_maxim()
2185 		 * MAX6659 has a third set of upper temperature limit registers.  in lm90_detect_maxim()
2196 			 * We know that this is not a MAX6657/58/59 because its  in lm90_detect_maxim()
2198 			 * not appear to have a conversion rate register.  in lm90_detect_maxim()
2201 			/* re-read manufacturer ID to have a good baseline */  in lm90_detect_maxim()
2238 		 * and MAX6649 is at address 0x4c. A slight difference between  in lm90_detect_maxim()
2336 	 * 0x4c and have a chip ID of 0x01. G781-1 is supposed to be at I2C  in lm90_detect_gmt()
2337 	 * address 0x4d and have a chip ID of 0x03. However, when support  in lm90_detect_gmt()
2338 	 * for G781 was added, chips at 0x4c and 0x4d were found to have a  in lm90_detect_gmt()
2339 	 * chip ID of 0x01. A G781-1 at I2C address 0x4d was now found with  in lm90_detect_gmt()
2343 	 * G784 reports manufacturer ID 0x47 and chip ID 0x01. A public  in lm90_detect_gmt()
2447 	 * value. Check again with a different register and handle accordingly.  in lm90_detect()
2570 	 * Note that expeciments with an actual chip do not show a difference  in lm90_init_client()