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Diffstat (limited to 'Documentation/hwmon/pmbus')
| -rw-r--r-- | Documentation/hwmon/pmbus | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/Documentation/hwmon/pmbus b/Documentation/hwmon/pmbus new file mode 100644 index 000000000000..5e462fc7f99b --- /dev/null +++ b/Documentation/hwmon/pmbus @@ -0,0 +1,197 @@ +Kernel driver pmbus +==================== + +Supported chips: + * Ericsson BMR45X series + DC/DC Converter + Prefixes: 'bmr450', 'bmr451', 'bmr453', 'bmr454' + Addresses scanned: - + Datasheet: + http://archive.ericsson.net/service/internet/picov/get?DocNo=28701-EN/LZT146395 + * Linear Technology LTC2978 + Octal PMBus Power Supply Monitor and Controller + Prefix: 'ltc2978' + Addresses scanned: - + Datasheet: http://cds.linear.com/docs/Datasheet/2978fa.pdf + * Generic PMBus devices + Prefix: 'pmbus' + Addresses scanned: - + Datasheet: n.a. + +Author: Guenter Roeck <guenter.roeck@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. + +Fan support will be added in a later version of this driver. + + +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 + + +Platform data support +--------------------- + +Support for additional PMBus chips can be added by defining chip parameters in +a new chip specific driver file. For example, (untested) code to add support for +Emerson DS1200 power modules might look as follows. + +static struct pmbus_driver_info ds1200_info = { + .pages = 1, + /* Note: All other sensors are in linear mode */ + .direct[PSC_VOLTAGE_OUT] = true, + .direct[PSC_TEMPERATURE] = true, + .direct[PSC_CURRENT_OUT] = true, + .m[PSC_VOLTAGE_IN] = 1, + .b[PSC_VOLTAGE_IN] = 0, + .R[PSC_VOLTAGE_IN] = 3, + .m[PSC_VOLTAGE_OUT] = 1, + .b[PSC_VOLTAGE_OUT] = 0, + .R[PSC_VOLTAGE_OUT] = 3, + .m[PSC_TEMPERATURE] = 1, + .b[PSC_TEMPERATURE] = 0, + .R[PSC_TEMPERATURE] = 3, + .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN | PMBUS_HAVE_STATUS_INPUT + | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT + | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT + | PMBUS_HAVE_PIN | PMBUS_HAVE_POUT + | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP + | PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12, +}; + +static int ds1200_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + return pmbus_do_probe(client, id, &ds1200_info); +} + +static int ds1200_remove(struct i2c_client *client) +{ + return pmbus_do_remove(client); +} + +static const struct i2c_device_id ds1200_id[] = { + {"ds1200", 0}, + {} +}; + +MODULE_DEVICE_TABLE(i2c, ds1200_id); + +/* This is the driver that will be inserted */ +static struct i2c_driver ds1200_driver = { + .driver = { + .name = "ds1200", + }, + .probe = ds1200_probe, + .remove = ds1200_remove, + .id_table = ds1200_id, +}; + +static int __init ds1200_init(void) +{ + return i2c_add_driver(&ds1200_driver); +} + +static void __exit ds1200_exit(void) +{ + i2c_del_driver(&ds1200_driver); +} + + +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. Limits are read-write; all other +attributes are read-only. + +inX_input Measured voltage. From READ_VIN or READ_VOUT register. +inX_min Minimum 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_lcrit Critical minimum Voltage. + From VIN_UV_FAULT_LIMIT or VOUT_UV_FAULT_LIMIT register. +inX_crit Critical maximum voltage. + From VIN_OV_FAULT_LIMIT or VOUT_OV_FAULT_LIMIT register. +inX_min_alarm Voltage low alarm. From VOLTAGE_UV_WARNING status. +inX_max_alarm Voltage high alarm. From VOLTAGE_OV_WARNING status. +inX_lcrit_alarm Voltage critical low alarm. + From VOLTAGE_UV_FAULT status. +inX_crit_alarm Voltage critical high alarm. + From VOLTAGE_OV_FAULT status. +inX_label "vin", "vcap", or "voutY" + +currX_input Measured current. From READ_IIN or READ_IOUT register. +currX_max Maximum current. + From IIN_OC_WARN_LIMIT or IOUT_OC_WARN_LIMIT register. +currX_lcrit Critical minimum output current. + From IOUT_UC_FAULT_LIMIT register. +currX_crit Critical maximum current. + From IIN_OC_FAULT_LIMIT or IOUT_OC_FAULT_LIMIT register. +currX_alarm Current high alarm. + From IIN_OC_WARNING or IOUT_OC_WARNING status. +currX_max_alarm Current high alarm. + From IIN_OC_WARN_LIMIT or IOUT_OC_WARN_LIMIT status. +currX_lcrit_alarm Output current critical low alarm. + From IOUT_UC_FAULT status. +currX_crit_alarm Current critical high alarm. + From IIN_OC_FAULT or IOUT_OC_FAULT status. +currX_label "iin" or "ioutY" + +powerX_input Measured power. From READ_PIN or READ_POUT register. +powerX_cap Output power cap. From POUT_MAX register. +powerX_max Power limit. From PIN_OP_WARN_LIMIT or + POUT_OP_WARN_LIMIT register. +powerX_crit Critical output power limit. + From POUT_OP_FAULT_LIMIT register. +powerX_alarm Power high alarm. + From PIN_OP_WARNING or POUT_OP_WARNING status. +powerX_crit_alarm Output power critical high alarm. + From POUT_OP_FAULT status. +powerX_label "pin" or "poutY" + +tempX_input Measured temperature. + From READ_TEMPERATURE_X register. +tempX_min Mimimum temperature. From UT_WARN_LIMIT register. +tempX_max Maximum temperature. From OT_WARN_LIMIT register. +tempX_lcrit Critical low temperature. + From UT_FAULT_LIMIT register. +tempX_crit Critical high temperature. + 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_lcrit_alarm Chip temperature critical low alarm. Set by comparing + READ_TEMPERATURE_X with UT_FAULT_LIMIT if + TEMP_UT_FAULT status is set. +tempX_crit_alarm Chip temperature critical high alarm. Set by comparing + READ_TEMPERATURE_X with OT_FAULT_LIMIT if + TEMP_OT_FAULT status is set. |
