hwmon: (adt7475) Add support for the ADT7490

Add support for the Analog Devices ADT7490 chip. This chip is largely
compatible with the ADT7473 and ADT7475, with additional features.
In particular, it has 6 voltage inputs instead of 2.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Jordan Crouse <jordan@cosmicpenguin.net>
Cc: "Darrick J. Wong" <djwong@us.ibm.com>

1 files changed, 29 insertions, 5 deletions

diff --git a/Documentation/hwmon/adt7475 b/Documentation/hwmon/adt7475
index ebfee5524020..f08f28715b84 100644
--- a/Documentation/hwmon/adt7475
+++ b/Documentation/hwmon/adt7475
@@ -10,24 +10,31 @@ Supported chips:
     Prefix: 'adt7475'
     Addresses scanned: I2C 0x2E
     Datasheet: Publicly available at the On Semiconductors website
+  * Analog Devices ADT7490
+    Prefix: 'adt7490'
+    Addresses scanned: I2C 0x2C, 0x2D, 0x2E
+    Datasheet: Publicly available at the On Semiconductors website
 
 Authors:
         Jordan Crouse
         Hans de Goede
         Darrick J. Wong (documentation)
+        Jean Delvare
 
 
 Description
 -----------
 
-This driver implements support for the Analog Devices ADT7473 and ADT7475
-chip family. Both chips differ only in minor details. They will be
-collectively designed by the name "ADT747x" in the rest of this document.
+This driver implements support for the Analog Devices ADT7473, ADT7475 and
+ADT7490 chip family. The ADT7473 and ADT7475 differ only in minor details.
+The ADT7490 has additional features, including extra voltage measurement
+inputs and PECI support. All the supported chips will be collectively
+designed by the name "ADT747x" in the rest of this document.
 
 The ADT747x uses the 2-wire interface compatible with the SMBus 2.0
 specification. Using an analog to digital converter it measures three (3)
-temperatures and two (2) voltages. It has four (4) 16-bit counters for
-measuring fan speed. There are three (3) PWM outputs that can be used
+temperatures and two (2) or more voltages. It has four (4) 16-bit counters
+for measuring fan speed. There are three (3) PWM outputs that can be used
 to control fan speed.
 
 A sophisticated control system for the PWM outputs is designed into the
@@ -45,6 +52,23 @@ The ADT747x samples all inputs continuously. The driver will not read
 the registers more often than once every other second. Further,
 configuration data is only read once per minute.
 
+Chip Differences Summary
+------------------------
+
+ADT7473:
+  * 2 voltage inputs
+  * system acoustics optimizations (not implemented)
+
+ADT7475:
+  * 2 voltage inputs
+
+ADT7490:
+  * 6 voltage inputs
+  * 1 Imon input (not implemented)
+  * PECI support (not implemented)
+  * 2 GPIO pins (not implemented)
+  * system acoustics optimizations (not implemented)
+
 Special Features
 ----------------