hwmon: (pmbus) Support for TI UCD90xxx series Sequencer and System Health Controllers

Hardware monitoring support for TI UCD90120, UCD90124, UCD9090, and UCD90910
Sequencer and System Health Controllers.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Reviewed-by: Tom Grennan <tom.grennan@ericsson.com>

Documentation/hwmon/ucd9000

@@ -0,0 +1,110 @@
+Kernel driver ucd9000
+=====================
+
+Supported chips:
+  * TI UCD90120, UCD90124, UCD9090, and UCD90910
+    Prefixes: 'ucd90120', 'ucd90124', 'ucd9090', 'ucd90910'
+    Addresses scanned: -
+    Datasheets:
+	http://focus.ti.com/lit/ds/symlink/ucd90120.pdf
+	http://focus.ti.com/lit/ds/symlink/ucd90124.pdf
+	http://focus.ti.com/lit/ds/symlink/ucd9090.pdf
+	http://focus.ti.com/lit/ds/symlink/ucd90910.pdf
+
+Author: Guenter Roeck <guenter.roeck@ericsson.com>
+
+
+Description
+-----------
+
+From datasheets:
+
+The UCD90120 Power Supply Sequencer and System Health Monitor monitors and
+sequences up to 12 independent voltage rails. The device integrates a 12-bit
+ADC with a 2.5V internal reference for monitoring up to 13 power supply voltage,
+current, or temperature inputs.
+
+The UCD90124 is a 12-rail PMBus/I2C addressable power-supply sequencer and
+system-health monitor. The device integrates a 12-bit ADC for monitoring up to
+13 power-supply voltage, current, or temperature inputs. Twenty-six GPIO pins
+can be used for power supply enables, power-on reset signals, external
+interrupts, cascading, or other system functions. Twelve of these pins offer PWM
+functionality. Using these pins, the UCD90124 offers support for fan control,
+margining, and general-purpose PWM functions.
+
+The UCD9090 is a 10-rail PMBus/I2C addressable power-supply sequencer and
+monitor. The device integrates a 12-bit ADC for monitoring up to 10 power-supply
+voltage inputs. Twenty-three GPIO pins can be used for power supply enables,
+power-on reset signals, external interrupts, cascading, or other system
+functions. Ten of these pins offer PWM functionality. Using these pins, the
+UCD9090 offers support for margining, and general-purpose PWM functions.
+
+The UCD90910 is a ten-rail I2C / PMBus addressable power-supply sequencer and
+system-health monitor. The device integrates a 12-bit ADC for monitoring up to
+13 power-supply voltage, current, or temperature inputs.
+
+This driver is a client driver to the core PMBus driver. Please see
+Documentation/hwmon/pmbus for details on PMBus client drivers.
+
+
+Usage Notes
+-----------
+
+This driver does not auto-detect devices. You will have to instantiate the
+devices explicitly. Please see Documentation/i2c/instantiating-devices for
+details.
+
+
+Platform data support
+---------------------
+
+The driver supports standard PMBus driver platform data. Please see
+Documentation/hwmon/pmbus for details.
+
+
+Sysfs entries
+-------------
+
+The following attributes are supported. Limits are read-write; all other
+attributes are read-only.
+
+in[1-12]_label		"vout[1-12]".
+in[1-12]_input		Measured voltage. From READ_VOUT register.
+in[1-12]_min		Minumum Voltage. From VOUT_UV_WARN_LIMIT register.
+in[1-12]_max		Maximum voltage. From VOUT_OV_WARN_LIMIT register.
+in[1-12]_lcrit		Critical minumum Voltage. VOUT_UV_FAULT_LIMIT register.
+in[1-12]_crit		Critical maximum voltage. From VOUT_OV_FAULT_LIMIT register.
+in[1-12]_min_alarm	Voltage low alarm. From VOLTAGE_UV_WARNING status.
+in[1-12]_max_alarm	Voltage high alarm. From VOLTAGE_OV_WARNING status.
+in[1-12]_lcrit_alarm	Voltage critical low alarm. From VOLTAGE_UV_FAULT status.
+in[1-12]_crit_alarm	Voltage critical high alarm. From VOLTAGE_OV_FAULT status.
+
+curr[1-12]_label	"iout[1-12]".
+curr[1-12]_input	Measured current. From READ_IOUT register.
+curr[1-12]_max		Maximum current. From IOUT_OC_WARN_LIMIT register.
+curr[1-12]_lcrit	Critical minumum output current. From IOUT_UC_FAULT_LIMIT
+			register.
+curr[1-12]_crit		Critical maximum current. From IOUT_OC_FAULT_LIMIT register.
+curr[1-12]_max_alarm	Current high alarm. From IOUT_OC_WARNING status.
+curr[1-12]_crit_alarm	Current critical high alarm. From IOUT_OC_FAULT status.
+
+			For each attribute index, either voltage or current is
+			reported, but not both. If voltage or current is
+			reported depends on the chip configuration.
+
+temp[1-2]_input		Measured temperatures. From READ_TEMPERATURE_1 and
+			READ_TEMPERATURE_2 registers.
+temp[1-2]_max		Maximum temperature. From OT_WARN_LIMIT register.
+temp[1-2]_crit		Critical high temperature. From OT_FAULT_LIMIT register.
+temp[1-2]_max_alarm	Temperature high alarm.
+temp[1-2]_crit_alarm	Temperature critical high alarm.
+
+fan[1-4]_input		Fan RPM.
+fan[1-4]_alarm		Fan alarm.
+fan[1-4]_fault		Fan fault.
+
+			Fan attributes are only available on chips supporting
+			fan control (UCD90124, UCD90910). Attribute files are
+			created only for enabled fans.
+			Note that even though UCD90910 supports up to 10 fans,
+			only up to four fans are currently supported.