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   * Maxim MAX16064
  17     Quad Power-Supply Controller
  18     Prefix: 'max16064'
  19     Addresses scanned: -
  20     Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX16064.pdf
  21   * Maxim MAX34440
  22     PMBus 6-Channel Power-Supply Manager
  23     Prefixes: 'max34440'
  24     Addresses scanned: -
  25     Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX34440.pdf
  26   * Maxim MAX34441
  27     PMBus 5-Channel Power-Supply Manager and Intelligent Fan Controller
  28     Prefixes: 'max34441'
  29     Addresses scanned: -
  30     Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX34441.pdf
  31   * Maxim MAX8688
  32     Digital Power-Supply Controller/Monitor
  33     Prefix: 'max8688'
  34     Addresses scanned: -
  35     Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX8688.pdf
  36   * Generic PMBus devices
  37     Prefix: 'pmbus'
  38     Addresses scanned: -
  39     Datasheet: n.a.
  40
  41 Author: Guenter Roeck <guenter.roeck@ericsson.com>
  42
  43
  44 Description
  45 -----------
  46
  47 This driver supports hardware montoring for various PMBus compliant devices.
  48 It supports voltage, current, power, and temperature sensors as supported
  49 by the device.
  50
  51 Each monitored channel has its own high and low limits, plus a critical
  52 limit.
  53
  54 Fan support will be added in a later version of this driver.
  55
  56
  57 Usage Notes
  58 -----------
  59
  60 This driver does not probe for PMBus devices, since there is no register
  61 which can be safely used to identify the chip (The MFG_ID register is not
  62 supported by all chips), and since there is no well defined address range for
  63 PMBus devices. You will have to instantiate the devices explicitly.
  64
  65 Example: the following will load the driver for an LTC2978 at address 0x60
  66 on I2C bus #1:
  67 $ modprobe pmbus
  68 $ echo ltc2978 0x60 > /sys/bus/i2c/devices/i2c-1/new_device
  69
  70
  71 Platform data support
  72 ---------------------
  73
  74 Support for additional PMBus chips can be added by defining chip parameters in
  75 a new chip specific driver file. For example, (untested) code to add support for
  76 Emerson DS1200 power modules might look as follows.
  77
  78 static struct pmbus_driver_info ds1200_info = {
  79         .pages = 1,
  80         /* Note: All other sensors are in linear mode */
  81         .direct[PSC_VOLTAGE_OUT] = true,
  82         .direct[PSC_TEMPERATURE] = true,
  83         .direct[PSC_CURRENT_OUT] = true,
  84         .m[PSC_VOLTAGE_IN] = 1,
  85         .b[PSC_VOLTAGE_IN] = 0,
  86         .R[PSC_VOLTAGE_IN] = 3,
  87         .m[PSC_VOLTAGE_OUT] = 1,
  88         .b[PSC_VOLTAGE_OUT] = 0,
  89         .R[PSC_VOLTAGE_OUT] = 3,
  90         .m[PSC_TEMPERATURE] = 1,
  91         .b[PSC_TEMPERATURE] = 0,
  92         .R[PSC_TEMPERATURE] = 3,
  93         .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN | PMBUS_HAVE_STATUS_INPUT
  94                    | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
  95                    | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
  96                    | PMBUS_HAVE_PIN | PMBUS_HAVE_POUT
  97                    | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP
  98                    | PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12,
  99 };
 100
 101 static int ds1200_probe(struct i2c_client *client,
 102                         const struct i2c_device_id *id)
 103 {
 104         return pmbus_do_probe(client, id, &ds1200_info);
 105 }
 106
 107 static int ds1200_remove(struct i2c_client *client)
 108 {
 109         return pmbus_do_remove(client);
 110 }
 111
 112 static const struct i2c_device_id ds1200_id[] = {
 113         {"ds1200", 0},
 114         {}
 115 };
 116
 117 MODULE_DEVICE_TABLE(i2c, ds1200_id);
 118
 119 /* This is the driver that will be inserted */
 120 static struct i2c_driver ds1200_driver = {
 121         .driver = {
 122                    .name = "ds1200",
 123                    },
 124         .probe = ds1200_probe,
 125         .remove = ds1200_remove,
 126         .id_table = ds1200_id,
 127 };
 128
 129 static int __init ds1200_init(void)
 130 {
 131         return i2c_add_driver(&ds1200_driver);
 132 }
 133
 134 static void __exit ds1200_exit(void)
 135 {
 136         i2c_del_driver(&ds1200_driver);
 137 }
 138
 139
 140 Sysfs entries
 141 -------------
 142
 143 When probing the chip, the driver identifies which PMBus registers are
 144 supported, and determines available sensors from this information.
 145 Attribute files only exist if respective sensors are suported by the chip.
 146 Labels are provided to inform the user about the sensor associated with
 147 a given sysfs entry.
 148
 149 The following attributes are supported. Limits are read-write; all other
 150 attributes are read-only.
 151
 152 inX_input               Measured voltage. From READ_VIN or READ_VOUT register.
 153 inX_min                 Minimum Voltage.
 154                         From VIN_UV_WARN_LIMIT or VOUT_UV_WARN_LIMIT register.
 155 inX_max                 Maximum voltage.
 156                         From VIN_OV_WARN_LIMIT or VOUT_OV_WARN_LIMIT register.
 157 inX_lcrit               Critical minimum Voltage.
 158                         From VIN_UV_FAULT_LIMIT or VOUT_UV_FAULT_LIMIT register.
 159 inX_crit                Critical maximum voltage.
 160                         From VIN_OV_FAULT_LIMIT or VOUT_OV_FAULT_LIMIT register.
 161 inX_min_alarm           Voltage low alarm. From VOLTAGE_UV_WARNING status.
 162 inX_max_alarm           Voltage high alarm. From VOLTAGE_OV_WARNING status.
 163 inX_lcrit_alarm         Voltage critical low alarm.
 164                         From VOLTAGE_UV_FAULT status.
 165 inX_crit_alarm          Voltage critical high alarm.
 166                         From VOLTAGE_OV_FAULT status.
 167 inX_label               "vin", "vcap", or "voutY"
 168
 169 currX_input             Measured current. From READ_IIN or READ_IOUT register.
 170 currX_max               Maximum current.
 171                         From IIN_OC_WARN_LIMIT or IOUT_OC_WARN_LIMIT register.
 172 currX_lcrit             Critical minimum output current.
 173                         From IOUT_UC_FAULT_LIMIT register.
 174 currX_crit              Critical maximum current.
 175                         From IIN_OC_FAULT_LIMIT or IOUT_OC_FAULT_LIMIT register.
 176 currX_alarm             Current high alarm.
 177                         From IIN_OC_WARNING or IOUT_OC_WARNING status.
 178 currX_lcrit_alarm       Output current critical low alarm.
 179                         From IOUT_UC_FAULT status.
 180 currX_crit_alarm        Current critical high alarm.
 181                         From IIN_OC_FAULT or IOUT_OC_FAULT status.
 182 currX_label             "iin" or "vinY"
 183
 184 powerX_input            Measured power. From READ_PIN or READ_POUT register.
 185 powerX_cap              Output power cap. From POUT_MAX register.
 186 powerX_max              Power limit. From PIN_OP_WARN_LIMIT or
 187                         POUT_OP_WARN_LIMIT register.
 188 powerX_crit             Critical output power limit.
 189                         From POUT_OP_FAULT_LIMIT register.
 190 powerX_alarm            Power high alarm.
 191                         From PIN_OP_WARNING or POUT_OP_WARNING status.
 192 powerX_crit_alarm       Output power critical high alarm.
 193                         From POUT_OP_FAULT status.
 194 powerX_label            "pin" or "poutY"
 195
 196 tempX_input             Measured tempererature.
 197                         From READ_TEMPERATURE_X register.
 198 tempX_min               Mimimum tempererature. From UT_WARN_LIMIT register.
 199 tempX_max               Maximum tempererature. From OT_WARN_LIMIT register.
 200 tempX_lcrit             Critical low tempererature.
 201                         From UT_FAULT_LIMIT register.
 202 tempX_crit              Critical high tempererature.
 203                         From OT_FAULT_LIMIT register.
 204 tempX_min_alarm         Chip temperature low alarm. Set by comparing
 205                         READ_TEMPERATURE_X with UT_WARN_LIMIT if
 206                         TEMP_UT_WARNING status is set.
 207 tempX_max_alarm         Chip temperature high alarm. Set by comparing
 208                         READ_TEMPERATURE_X with OT_WARN_LIMIT if
 209                         TEMP_OT_WARNING status is set.
 210 tempX_lcrit_alarm       Chip temperature critical low alarm. Set by comparing
 211                         READ_TEMPERATURE_X with UT_FAULT_LIMIT if
 212                         TEMP_UT_FAULT status is set.
 213 tempX_crit_alarm        Chip temperature critical high alarm. Set by comparing
 214                         READ_TEMPERATURE_X with OT_FAULT_LIMIT if
 215                         TEMP_OT_FAULT status is set.