From: Guenter Roeck on
Signed-off-by: Guenter Roeck <guenter.roeck(a)ericsson.com>
---
Documentation/hwmon/pmbus | 117 +++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 117 insertions(+), 0 deletions(-)
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+Kernel driver pmbus
+====================
+
+Supported chips:
+ * Ericsson BMR45X series
+ DC/DC Converter
+ Prefix: 'bmr45x'
+ Addresses scanned: -
+ Datasheets: Publicly available at the Ericsson website.
+ * Linear Technology LTC2978
+ Octal PMBus Power Supply Monitor and Controller
+ Prefix: 'ltc2978'
+ Addresses scanned: -
+ Datasheet: Publicly available at the Linear Technology website.
+ * Maxim MAX16064
+ Quad Power-Supply Controller
+ Prefix: 'max16064'
+ Addresses scanned: -
+ Datasheet: Publicly available at the Maxim website.
+ * Maxim MAX8688
+ Digital Power-Supply Controller/Monitor
+ Prefix: 'max8688'
+ Addresses scanned: -
+ Datasheet: Publicly available at the Maxim website.
+ * Texas Instruments UCD92xx
+ Digital PWM System Controller
+ Prefix: 'ucd921x', 'ucd9220', 'ucd9240'
+ Addresses scanned: -
+ Datasheets: Publicly available at the Philips website.
+ * Generic PMBus devices
+ Prefix: 'pmbus'
+ Addresses scanned: -
+ Datasheet: n.a.
+
+Author: Guenter Roeck <guenter.roeck(a)ericsson.com>
+
+
+Description
+-----------
+
+This driver supports hardware montoring for various PMBus compliant devices.
+It supports voltage, current, power, and temperature sensors as supported
+by the device.
+
+Each monitored channel has its own high and low limits, plus a critical
+limit.
+
+
+Usage Notes
+-----------
+
+This driver does not probe for PMBus devices, since there is no register
+which can be safely used to identify the chip (The MFG_ID register is not
+supported by all chips), and since there is no well defined address range for
+PMBus devices. You will have to instantiate the devices explicitly.
+
+Example: the following will load the driver for an LTC2978 at address 0x60
+on I2C bus #1:
+$ modprobe pmbus
+$ echo ltc2978 0x60 > /sys/bus/i2c/devices/i2c-1/new_device
+
+
+Sysfs entries
+-------------
+
+When probing the chip, the driver identifies which PMBus registers are
+supported, and determines available sensors from this information.
+Attribute files only exist if respective sensors are suported by the chip.
+Labels are provided to inform the user about the sensor associated with
+a given sysfs entry.
+
+The following attributes are supported. Limit attributes are read-write; all
+other attributes are read-only.
+
+inX_input Measured Voltage. From READ_VIN or READ_VOUT register.
+inX_min Minumum Voltage. From VIN_UV_WARN_LIMIT or
+ VOUT_UV_WARN_LIMIT register.
+inX_max Maximum Voltage. From VIN_OV_WARN_LIMIT or
+ VOUT_OV_WARN_LIMIT register.
+inX_min_alarm From VOLTAGE_UV_WARNING status.
+inX_max_alarm From VOLTAGE_OV_WARNING status.
+inX_min_fault From VOLTAGE_UV_FAULT status.
+inX_max_fault From VOLTAGE_OV_FAULT status.
+inX_label "vin" or "voutY"
+
+currX_input Measured Current. From READ_IIN or READ_IOUT register.
+currX_min Minumum Current. For output current only.
+ From IOUT_UC_FAULT_LIMIT register.
+currX_max Maximum Current. From IIN_OC_WARN_LIMIT or
+ IOUT_OC_WARN_LIMIT register.
+currX_min_alarm For output current only. From IOUT_UC_FAULT status.
+currX_max_alarm From IIN_OC_WARNING or IOUT_OC_WARNING status.
+currX_label "iin" or "vinY"
+
+powerX_input Measured Power. From READ_PIN or READ_POUT register.
+powerX_cap Power limit. From POUT_MAX register.
+powerX_max Power limit. From PIN_OP_WARN_LIMIT or
+ POUT_OP_WARN_LIMIT register.
+powerX_crit Critical power limit. From POUT_OP_FAULT_LIMIT register.
+powerX_alarm From POUT_OP_WARNING status.
+powerX_label "pin" or "poutY"
+
+tempX_input Measured tempererature. From READ_TEMPERATURE_X
+ register.
+tempX_min Mimimum tempererature. From UT_WARN_LIMIT register.
+tempX_max Maximum tempererature. From OT_WARN_LIMIT register.
+tempX_crit Critical high tempererature. From OT_FAULT_LIMIT
+ register.
+tempX_min_alarm Chip temperature low alarm. Set by comparing
+ READ_TEMPERATURE_X with UT_WARN_LIMIT if
+ TEMP_UT_WARNING status is set.
+tempX_max_alarm Chip temperature high alarm. Set by comparing
+ READ_TEMPERATURE_X with OT_WARN_LIMIT if
+ TEMP_OT_WARNING status is set.
+tempX_crit_alarm Chip temperature critical alarm. Set by comparing
+ READ_TEMPERATURE_X with OT_FAULT_LIMIT if
+ TEMP_OT_FAULT status is set.
--
1.7.0.87.g0901d

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