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hwmon: (lm90) Add support for MAX6690

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MAX6690 is all but identical to MAX6654. Revision 1 of its
datasheet lists the same chip ID as MAX6654, and a chip labeled
MAX6654 was found to have the chip ID listed as MAX6690 chip ID
in Revision 2 of its datasheet.

A devicetree node is not added for this chip since it is quite unlikely
that such an old chip will ever be used in a devicetree based system.
It can be added later if needed.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Guenter Roeck 2021-11-12 22:03:31 -08:00
parent 9888775be8
commit 399a8a0046
2 changed files with 17 additions and 2 deletions
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2
Documentation/hwmon/lm90.rst
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@ -370,7 +370,7 @@ MAX6648, MAX6692:
* Better local resolution
* Unsigned temperature
MAX6654:
MAX6654, MAX6690:
* Better local resolution
* Selectable address
* Remote sensor type selection

17
drivers/hwmon/lm90.c
View File

@ -42,7 +42,8 @@
* accordingly, and is done during initialization. Extended precision is only
* available at conversion rates of 1 Hz and slower. Note that extended
* precision is not enabled by default, as this driver initializes all chips
* to 2 Hz by design.
* to 2 Hz by design. The driver also supports MAX6690, which is practically
* identical to MAX6654.
*
* This driver also supports the MAX6646, MAX6647, MAX6648, MAX6649 and
* MAX6692 chips made by Maxim. These are again similar to the LM86,
@ -237,6 +238,7 @@ static const struct i2c_device_id lm90_id[] = {
{ "max6659", max6659 },
{ "max6680", max6680 },
{ "max6681", max6680 },
{ "max6690", max6654 },
{ "max6692", max6648 },
{ "max6695", max6696 },
{ "max6696", max6696 },
@ -1718,6 +1720,19 @@ static const char *lm90_detect_maxim(struct i2c_client *client, int chip_id,
if (!(config1 & 0x07) && convrate <= 0x07)
name = "max6654";
break;
case 0x09:
/*
* The chip_id of the MAX6690 holds the revision of the chip.
* The lowest 3 bits of the config1 register are unused and
* should return zero when read.
* Note that MAX6654 and MAX6690 are practically the same chips.
* The only diference is the rated accuracy. Rev. 1 of the
* MAX6690 datasheet lists a chip ID of 0x08, and a chip labeled
* MAX6654 was observed to have a chip ID of 0x09.
*/
if (!(config1 & 0x07) && convrate <= 0x07)
name = "max6690";
break;
case 0x4d:
/*
* The MAX6657, MAX6658 and MAX6659 do NOT have a chip_id