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-rw-r--r--Documentation/hwmon/ds1621144
-rw-r--r--Documentation/hwmon/g76265
-rw-r--r--Documentation/hwmon/ina2xx4
3 files changed, 202 insertions, 11 deletions
diff --git a/Documentation/hwmon/ds1621 b/Documentation/hwmon/ds1621
index 5e97f333c4df..896cdc972ca8 100644
--- a/Documentation/hwmon/ds1621
+++ b/Documentation/hwmon/ds1621
@@ -2,16 +2,30 @@ Kernel driver ds1621
====================
Supported chips:
- * Dallas Semiconductor DS1621
+ * Dallas Semiconductor / Maxim Integrated DS1621
Prefix: 'ds1621'
- Addresses scanned: I2C 0x48 - 0x4f
- Datasheet: Publicly available at the Dallas Semiconductor website
- http://www.dalsemi.com/
+ Addresses scanned: none
+ Datasheet: Publicly available from www.maximintegrated.com
+
* Dallas Semiconductor DS1625
- Prefix: 'ds1621'
- Addresses scanned: I2C 0x48 - 0x4f
- Datasheet: Publicly available at the Dallas Semiconductor website
- http://www.dalsemi.com/
+ Prefix: 'ds1625'
+ Addresses scanned: none
+ Datasheet: Publicly available from www.datasheetarchive.com
+
+ * Maxim Integrated DS1631
+ Prefix: 'ds1631'
+ Addresses scanned: none
+ Datasheet: Publicly available from www.maximintegrated.com
+
+ * Maxim Integrated DS1721
+ Prefix: 'ds1721'
+ Addresses scanned: none
+ Datasheet: Publicly available from www.maximintegrated.com
+
+ * Maxim Integrated DS1731
+ Prefix: 'ds1731'
+ Addresses scanned: none
+ Datasheet: Publicly available from www.maximintegrated.com
Authors:
Christian W. Zuckschwerdt <zany@triq.net>
@@ -59,5 +73,115 @@ any of the limits have ever been met or exceeded since last power-up or
reset. Be aware: When testing, it showed that the status of Tout can change
with neither of the alarms set.
-Temperature conversion of the DS1621 takes up to 1000ms; internal access to
-non-volatile registers may last for 10ms or below.
+Since there is no version or vendor identification register, there is
+no unique identification for these devices. Therefore, explicit device
+instantiation is required for correct device identification and functionality
+(one device per address in this address range: 0x48..0x4f).
+
+The DS1625 is pin compatible and functionally equivalent with the DS1621,
+but the DS1621 is meant to replace it. The DS1631, DS1721, and DS1731 are
+also pin compatible with the DS1621 and provide multi-resolution support.
+
+Additionally, the DS1721 data sheet says the temperature flags (THF and TLF)
+are used internally, however, these flags do get set and cleared as the actual
+temperature crosses the min or max settings (which by default are set to 75
+and 80 degrees respectively).
+
+Temperature Conversion:
+-----------------------
+DS1621 - 750ms (older devices may take up to 1000ms)
+DS1625 - 500ms
+DS1631 - 93ms..750ms for 9..12 bits resolution, respectively.
+DS1721 - 93ms..750ms for 9..12 bits resolution, respectively.
+DS1731 - 93ms..750ms for 9..12 bits resolution, respectively.
+
+Note:
+On the DS1621, internal access to non-volatile registers may last for 10ms
+or less (unverified on the other devices).
+
+Temperature Accuracy:
+---------------------
+DS1621: +/- 0.5 degree Celsius (from 0 to +70 degrees)
+DS1625: +/- 0.5 degree Celsius (from 0 to +70 degrees)
+DS1631: +/- 0.5 degree Celsius (from 0 to +70 degrees)
+DS1721: +/- 1.0 degree Celsius (from -10 to +85 degrees)
+DS1731: +/- 1.0 degree Celsius (from -10 to +85 degrees)
+
+Note:
+Please refer to the device datasheets for accuracy at other temperatures.
+
+Temperature Resolution:
+-----------------------
+As mentioned above, the DS1631, DS1721, and DS1731 provide multi-resolution
+support, which is achieved via the R0 and R1 config register bits, where:
+
+R0..R1
+------
+ 0 0 => 9 bits, 0.5 degrees Celcius
+ 1 0 => 10 bits, 0.25 degrees Celcius
+ 0 1 => 11 bits, 0.125 degrees Celcius
+ 1 1 => 12 bits, 0.0625 degrees Celcius
+
+Note:
+At initial device power-on, the default resolution is set to 12-bits.
+
+The resolution mode for the DS1631, DS1721, or DS1731 can be changed from
+userspace, via the device 'update_interval' sysfs attribute. This attribute
+will normalize the range of input values to the device maximum resolution
+values defined in the datasheet as follows:
+
+Resolution Conversion Time Input Range
+ (C/LSB) (msec) (msec)
+------------------------------------------------
+0.5 93.75 0....94
+0.25 187.5 95...187
+0.125 375 188..375
+0.0625 750 376..infinity
+------------------------------------------------
+
+The following examples show how the 'update_interval' attribute can be
+used to change the conversion time:
+
+$ cat update_interval
+750
+$ cat temp1_input
+22062
+$
+$ echo 300 > update_interval
+$ cat update_interval
+375
+$ cat temp1_input
+22125
+$
+$ echo 150 > update_interval
+$ cat update_interval
+188
+$ cat temp1_input
+22250
+$
+$ echo 1 > update_interval
+$ cat update_interval
+94
+$ cat temp1_input
+22000
+$
+$ echo 1000 > update_interval
+$ cat update_interval
+750
+$ cat temp1_input
+22062
+$
+
+As shown, the ds1621 driver automatically adjusts the 'update_interval'
+user input, via a step function. Reading back the 'update_interval' value
+after a write operation provides the conversion time used by the device.
+
+Mathematically, the resolution can be derived from the conversion time
+via the following function:
+
+ g(x) = 0.5 * [minimum_conversion_time/x]
+
+where:
+ -> 'x' = the output from 'update_interval'
+ -> 'g(x)' = the resolution in degrees C per LSB.
+ -> 93.75ms = minimum conversion time
diff --git a/Documentation/hwmon/g762 b/Documentation/hwmon/g762
new file mode 100644
index 000000000000..923db9c5b5bc
--- /dev/null
+++ b/Documentation/hwmon/g762
@@ -0,0 +1,65 @@
+Kernel driver g762
+==================
+
+The GMT G762 Fan Speed PWM Controller is connected directly to a fan
+and performs closed-loop or open-loop control of the fan speed. Two
+modes - PWM or DC - are supported by the device.
+
+For additional information, a detailed datasheet is available at
+http://natisbad.org/NAS/ref/GMT_EDS-762_763-080710-0.2.pdf. sysfs
+bindings are described in Documentation/hwmon/sysfs-interface.
+
+The following entries are available to the user in a subdirectory of
+/sys/bus/i2c/drivers/g762/ to control the operation of the device.
+This can be done manually using the following entries but is usually
+done via a userland daemon like fancontrol.
+
+Note that those entries do not provide ways to setup the specific
+hardware characteristics of the system (reference clock, pulses per
+fan revolution, ...); Those can be modified via devicetree bindings
+documented in Documentation/devicetree/bindings/hwmon/g762.txt or
+using a specific platform_data structure in board initialization
+file (see include/linux/platform_data/g762.h).
+
+ fan1_target: set desired fan speed. This only makes sense in closed-loop
+ fan speed control (i.e. when pwm1_enable is set to 2).
+
+ fan1_input: provide current fan rotation value in RPM as reported by
+ the fan to the device.
+
+ fan1_div: fan clock divisor. Supported value are 1, 2, 4 and 8.
+
+ fan1_pulses: number of pulses per fan revolution. Supported values
+ are 2 and 4.
+
+ fan1_fault: reports fan failure, i.e. no transition on fan gear pin for
+ about 0.7s (if the fan is not voluntarily set off).
+
+ fan1_alarm: in closed-loop control mode, if fan RPM value is 25% out
+ of the programmed value for over 6 seconds 'fan1_alarm' is
+ set to 1.
+
+ pwm1_enable: set current fan speed control mode i.e. 1 for manual fan
+ speed control (open-loop) via pwm1 described below, 2 for
+ automatic fan speed control (closed-loop) via fan1_target
+ above.
+
+ pwm1_mode: set or get fan driving mode: 1 for PWM mode, 0 for DC mode.
+
+ pwm1: get or set PWM fan control value in open-loop mode. This is an
+ integer value between 0 and 255. 0 stops the fan, 255 makes
+ it run at full speed.
+
+Both in PWM mode ('pwm1_mode' set to 1) and DC mode ('pwm1_mode' set to 0),
+when current fan speed control mode is open-loop ('pwm1_enable' set to 1),
+the fan speed is programmed by setting a value between 0 and 255 via 'pwm1'
+entry (0 stops the fan, 255 makes it run at full speed). In closed-loop mode
+('pwm1_enable' set to 2), the expected rotation speed in RPM can be passed to
+the chip via 'fan1_target'. In closed-loop mode, the target speed is compared
+with current speed (available via 'fan1_input') by the device and a feedback
+is performed to match that target value. The fan speed value is computed
+based on the parameters associated with the physical characteristics of the
+system: a reference clock source frequency, a number of pulses per fan
+revolution, etc.
+
+Note that the driver will update its values at most once per second.
diff --git a/Documentation/hwmon/ina2xx b/Documentation/hwmon/ina2xx
index 03444f9d833f..4223c2d3b508 100644
--- a/Documentation/hwmon/ina2xx
+++ b/Documentation/hwmon/ina2xx
@@ -44,4 +44,6 @@ The INA226 monitors both a shunt voltage drop and bus supply voltage.
The INA230 is a high or low side current shunt and power monitor with an I2C
interface. The INA230 monitors both a shunt voltage drop and bus supply voltage.
-The shunt value in micro-ohms can be set via platform data.
+The shunt value in micro-ohms can be set via platform data or device tree.
+Please refer to the Documentation/devicetree/bindings/i2c/ina2xx.txt for bindings
+if the device tree is used.