Documentation/hwmon/pmbus

   1 Kernel driver pmbus
   2 ====================
   3
   4 Supported chips:
   5   * Ericsson BMR45X series
   6     DC/DC Converter
   7     Prefixes: 'bmr450', 'bmr451', 'bmr453', 'bmr454'
   8     Addresses scanned: -
   9     Datasheet:
  10  http://archive.ericsson.net/service/internet/picov/get?DocNo=28701-EN/LZT146395
  11   * Linear Technology LTC2978
  12     Octal PMBus Power Supply Monitor and Controller
  13     Prefix: 'ltc2978'
  14     Addresses scanned: -
  15     Datasheet: http://cds.linear.com/docs/Datasheet/2978fa.pdf
  16   * Generic PMBus devices
  17     Prefix: 'pmbus'
  18     Addresses scanned: -
  19     Datasheet: n.a.
  20
  21 Author: Guenter Roeck <guenter.roeck@ericsson.com>
  22
  23
  24 Description
  25 -----------
  26
  27 This driver supports hardware montoring for various PMBus compliant devices.
  28 It supports voltage, current, power, and temperature sensors as supported
  29 by the device.
  30
  31 Each monitored channel has its own high and low limits, plus a critical
  32 limit.
  33
  34 Fan support will be added in a later version of this driver.
  35
  36
  37 Usage Notes
  38 -----------
  39
  40 This driver does not probe for PMBus devices, since there is no register
  41 which can be safely used to identify the chip (The MFG_ID register is not
  42 supported by all chips), and since there is no well defined address range for
  43 PMBus devices. You will have to instantiate the devices explicitly.
  44
  45 Example: the following will load the driver for an LTC2978 at address 0x60
  46 on I2C bus #1:
  47 $ modprobe pmbus
  48 $ echo ltc2978 0x60 > /sys/bus/i2c/devices/i2c-1/new_device
  49
  50
  51 Platform data support
  52 ---------------------
  53
  54 Support for additional PMBus chips can be added by defining chip parameters in
  55 a new chip specific driver file. For example, (untested) code to add support for
  56 Emerson DS1200 power modules might look as follows.
  57
  58 static struct pmbus_driver_info ds1200_info = {
  59         .pages = 1,
  60         /* Note: All other sensors are in linear mode */
  61         .direct[PSC_VOLTAGE_OUT] = true,
  62         .direct[PSC_TEMPERATURE] = true,
  63         .direct[PSC_CURRENT_OUT] = true,
  64         .m[PSC_VOLTAGE_IN] = 1,
  65         .b[PSC_VOLTAGE_IN] = 0,
  66         .R[PSC_VOLTAGE_IN] = 3,
  67         .m[PSC_VOLTAGE_OUT] = 1,
  68         .b[PSC_VOLTAGE_OUT] = 0,
  69         .R[PSC_VOLTAGE_OUT] = 3,
  70         .m[PSC_TEMPERATURE] = 1,
  71         .b[PSC_TEMPERATURE] = 0,
  72         .R[PSC_TEMPERATURE] = 3,
  73         .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN | PMBUS_HAVE_STATUS_INPUT
  74                    | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
  75                    | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
  76                    | PMBUS_HAVE_PIN | PMBUS_HAVE_POUT
  77                    | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP
  78                    | PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12,
  79 };
  80
  81 static int ds1200_probe(struct i2c_client *client,
  82                         const struct i2c_device_id *id)
  83 {
  84         return pmbus_do_probe(client, id, &ds1200_info);
  85 }
  86
  87 static int ds1200_remove(struct i2c_client *client)
  88 {
  89         return pmbus_do_remove(client);
  90 }
  91
  92 static const struct i2c_device_id ds1200_id[] = {
  93         {"ds1200", 0},
  94         {}
  95 };
  96
  97 MODULE_DEVICE_TABLE(i2c, ds1200_id);
  98
  99 /* This is the driver that will be inserted */
 100 static struct i2c_driver ds1200_driver = {
 101         .driver = {
 102                    .name = "ds1200",
 103                    },
 104         .probe = ds1200_probe,
 105         .remove = ds1200_remove,
 106         .id_table = ds1200_id,
 107 };
 108
 109 static int __init ds1200_init(void)
 110 {
 111         return i2c_add_driver(&ds1200_driver);
 112 }
 113
 114 static void __exit ds1200_exit(void)
 115 {
 116         i2c_del_driver(&ds1200_driver);
 117 }
 118
 119
 120 Sysfs entries
 121 -------------
 122
 123 When probing the chip, the driver identifies which PMBus registers are
 124 supported, and determines available sensors from this information.
 125 Attribute files only exist if respective sensors are suported by the chip.
 126 Labels are provided to inform the user about the sensor associated with
 127 a given sysfs entry.
 128
 129 The following attributes are supported. Limits are read-write; all other
 130 attributes are read-only.
 131
 132 inX_input               Measured voltage. From READ_VIN or READ_VOUT register.
 133 inX_min                 Minimum Voltage.
 134                         From VIN_UV_WARN_LIMIT or VOUT_UV_WARN_LIMIT register.
 135 inX_max                 Maximum voltage.
 136                         From VIN_OV_WARN_LIMIT or VOUT_OV_WARN_LIMIT register.
 137 inX_lcrit               Critical minimum Voltage.
 138                         From VIN_UV_FAULT_LIMIT or VOUT_UV_FAULT_LIMIT register.
 139 inX_crit                Critical maximum voltage.
 140                         From VIN_OV_FAULT_LIMIT or VOUT_OV_FAULT_LIMIT register.
 141 inX_min_alarm           Voltage low alarm. From VOLTAGE_UV_WARNING status.
 142 inX_max_alarm           Voltage high alarm. From VOLTAGE_OV_WARNING status.
 143 inX_lcrit_alarm         Voltage critical low alarm.
 144                         From VOLTAGE_UV_FAULT status.
 145 inX_crit_alarm          Voltage critical high alarm.
 146                         From VOLTAGE_OV_FAULT status.
 147 inX_label               "vin", "vcap", or "voutY"
 148
 149 currX_input             Measured current. From READ_IIN or READ_IOUT register.
 150 currX_max               Maximum current.
 151                         From IIN_OC_WARN_LIMIT or IOUT_OC_WARN_LIMIT register.
 152 currX_lcrit             Critical minimum output current.
 153                         From IOUT_UC_FAULT_LIMIT register.
 154 currX_crit              Critical maximum current.
 155                         From IIN_OC_FAULT_LIMIT or IOUT_OC_FAULT_LIMIT register.
 156 currX_alarm             Current high alarm.
 157                         From IIN_OC_WARNING or IOUT_OC_WARNING status.
 158 currX_max_alarm         Current high alarm.
 159                         From IIN_OC_WARN_LIMIT or IOUT_OC_WARN_LIMIT status.
 160 currX_lcrit_alarm       Output current critical low alarm.
 161                         From IOUT_UC_FAULT status.
 162 currX_crit_alarm        Current critical high alarm.
 163                         From IIN_OC_FAULT or IOUT_OC_FAULT status.
 164 currX_label             "iin" or "ioutY"
 165
 166 powerX_input            Measured power. From READ_PIN or READ_POUT register.
 167 powerX_cap              Output power cap. From POUT_MAX register.
 168 powerX_max              Power limit. From PIN_OP_WARN_LIMIT or
 169                         POUT_OP_WARN_LIMIT register.
 170 powerX_crit             Critical output power limit.
 171                         From POUT_OP_FAULT_LIMIT register.
 172 powerX_alarm            Power high alarm.
 173                         From PIN_OP_WARNING or POUT_OP_WARNING status.
 174 powerX_crit_alarm       Output power critical high alarm.
 175                         From POUT_OP_FAULT status.
 176 powerX_label            "pin" or "poutY"
 177
 178 tempX_input             Measured temperature.
 179                         From READ_TEMPERATURE_X register.
 180 tempX_min               Mimimum temperature. From UT_WARN_LIMIT register.
 181 tempX_max               Maximum temperature. From OT_WARN_LIMIT register.
 182 tempX_lcrit             Critical low temperature.
 183                         From UT_FAULT_LIMIT register.
 184 tempX_crit              Critical high temperature.
 185                         From OT_FAULT_LIMIT register.
 186 tempX_min_alarm         Chip temperature low alarm. Set by comparing
 187                         READ_TEMPERATURE_X with UT_WARN_LIMIT if
 188                         TEMP_UT_WARNING status is set.
 189 tempX_max_alarm         Chip temperature high alarm. Set by comparing
 190                         READ_TEMPERATURE_X with OT_WARN_LIMIT if
 191                         TEMP_OT_WARNING status is set.
 192 tempX_lcrit_alarm       Chip temperature critical low alarm. Set by comparing
 193                         READ_TEMPERATURE_X with UT_FAULT_LIMIT if
 194                         TEMP_UT_FAULT status is set.
 195 tempX_crit_alarm        Chip temperature critical high alarm. Set by comparing
 196                         READ_TEMPERATURE_X with OT_FAULT_LIMIT if
 197                         TEMP_OT_FAULT status is set.