Documentation/hwmon/pmbus.rst

   1 Kernel driver pmbus
   2 ===================
   3
   4 Supported chips:
   5
   6   * Ericsson BMR453, BMR454
   7
   8     Prefixes: 'bmr453', 'bmr454'
   9
  10     Addresses scanned: -
  11
  12     Datasheet:
  13
  14  http://archive.ericsson.net/service/internet/picov/get?DocNo=28701-EN/LZT146395
  15
  16   * ON Semiconductor ADP4000, NCP4200, NCP4208
  17
  18     Prefixes: 'adp4000', 'ncp4200', 'ncp4208'
  19
  20     Addresses scanned: -
  21
  22     Datasheets:
  23
  24         http://www.onsemi.com/pub_link/Collateral/ADP4000-D.PDF
  25
  26         http://www.onsemi.com/pub_link/Collateral/NCP4200-D.PDF
  27
  28         http://www.onsemi.com/pub_link/Collateral/JUNE%202009-%20REV.%200.PDF
  29
  30   * Lineage Power
  31
  32     Prefixes: 'mdt040', 'pdt003', 'pdt006', 'pdt012', 'udt020'
  33
  34     Addresses scanned: -
  35
  36     Datasheets:
  37
  38         http://www.lineagepower.com/oem/pdf/PDT003A0X.pdf
  39
  40         http://www.lineagepower.com/oem/pdf/PDT006A0X.pdf
  41
  42         http://www.lineagepower.com/oem/pdf/PDT012A0X.pdf
  43
  44         http://www.lineagepower.com/oem/pdf/UDT020A0X.pdf
  45
  46         http://www.lineagepower.com/oem/pdf/MDT040A0X.pdf
  47
  48   * Texas Instruments TPS40400, TPS544B20, TPS544B25, TPS544C20, TPS544C25
  49
  50     Prefixes: 'tps40400', 'tps544b20', 'tps544b25', 'tps544c20', 'tps544c25'
  51
  52     Addresses scanned: -
  53
  54     Datasheets:
  55
  56         http://www.ti.com/lit/gpn/tps40400
  57
  58         http://www.ti.com/lit/gpn/tps544b20
  59
  60         http://www.ti.com/lit/gpn/tps544b25
  61
  62         http://www.ti.com/lit/gpn/tps544c20
  63
  64         http://www.ti.com/lit/gpn/tps544c25
  65
  66   * Maxim MAX20796
  67
  68     Prefix: 'max20796'
  69
  70     Addresses scanned: -
  71
  72     Datasheet:
  73
  74         Not published
  75
  76   * Generic PMBus devices
  77
  78     Prefix: 'pmbus'
  79
  80     Addresses scanned: -
  81
  82     Datasheet: n.a.
  83
  84
  85 Author: Guenter Roeck <linux@roeck-us.net>
  86
  87
  88 Description
  89 -----------
  90
  91 This driver supports hardware monitoring for various PMBus compliant devices.
  92 It supports voltage, current, power, and temperature sensors as supported
  93 by the device.
  94
  95 Each monitored channel has its own high and low limits, plus a critical
  96 limit.
  97
  98 Fan support will be added in a later version of this driver.
  99
 100
 101 Usage Notes
 102 -----------
 103
 104 This driver does not probe for PMBus devices, since there is no register
 105 which can be safely used to identify the chip (The MFG_ID register is not
 106 supported by all chips), and since there is no well defined address range for
 107 PMBus devices. You will have to instantiate the devices explicitly.
 108
 109 Example: the following will load the driver for an LTC2978 at address 0x60
 110 on I2C bus #1::
 111
 112         $ modprobe pmbus
 113         $ echo ltc2978 0x60 > /sys/bus/i2c/devices/i2c-1/new_device
 114
 115
 116 Platform data support
 117 ---------------------
 118
 119 Support for additional PMBus chips can be added by defining chip parameters in
 120 a new chip specific driver file. For example, (untested) code to add support for
 121 Emerson DS1200 power modules might look as follows::
 122
 123   static struct pmbus_driver_info ds1200_info = {
 124         .pages = 1,
 125         /* Note: All other sensors are in linear mode */
 126         .direct[PSC_VOLTAGE_OUT] = true,
 127         .direct[PSC_TEMPERATURE] = true,
 128         .direct[PSC_CURRENT_OUT] = true,
 129         .m[PSC_VOLTAGE_IN] = 1,
 130         .b[PSC_VOLTAGE_IN] = 0,
 131         .R[PSC_VOLTAGE_IN] = 3,
 132         .m[PSC_VOLTAGE_OUT] = 1,
 133         .b[PSC_VOLTAGE_OUT] = 0,
 134         .R[PSC_VOLTAGE_OUT] = 3,
 135         .m[PSC_TEMPERATURE] = 1,
 136         .b[PSC_TEMPERATURE] = 0,
 137         .R[PSC_TEMPERATURE] = 3,
 138         .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN | PMBUS_HAVE_STATUS_INPUT
 139                    | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
 140                    | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
 141                    | PMBUS_HAVE_PIN | PMBUS_HAVE_POUT
 142                    | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP
 143                    | PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12,
 144   };
 145
 146   static int ds1200_probe(struct i2c_client *client,
 147                           const struct i2c_device_id *id)
 148   {
 149         return pmbus_do_probe(client, id, &ds1200_info);
 150   }
 151
 152   static int ds1200_remove(struct i2c_client *client)
 153   {
 154         return pmbus_do_remove(client);
 155   }
 156
 157   static const struct i2c_device_id ds1200_id[] = {
 158         {"ds1200", 0},
 159         {}
 160   };
 161
 162   MODULE_DEVICE_TABLE(i2c, ds1200_id);
 163
 164   /* This is the driver that will be inserted */
 165   static struct i2c_driver ds1200_driver = {
 166         .driver = {
 167                    .name = "ds1200",
 168                    },
 169         .probe = ds1200_probe,
 170         .remove = ds1200_remove,
 171         .id_table = ds1200_id,
 172   };
 173
 174   static int __init ds1200_init(void)
 175   {
 176         return i2c_add_driver(&ds1200_driver);
 177   }
 178
 179   static void __exit ds1200_exit(void)
 180   {
 181         i2c_del_driver(&ds1200_driver);
 182   }
 183
 184
 185 Sysfs entries
 186 -------------
 187
 188 When probing the chip, the driver identifies which PMBus registers are
 189 supported, and determines available sensors from this information.
 190 Attribute files only exist if respective sensors are supported by the chip.
 191 Labels are provided to inform the user about the sensor associated with
 192 a given sysfs entry.
 193
 194 The following attributes are supported. Limits are read-write; all other
 195 attributes are read-only.
 196
 197 ======================= ========================================================
 198 inX_input               Measured voltage. From READ_VIN or READ_VOUT register.
 199 inX_min                 Minimum Voltage.
 200                         From VIN_UV_WARN_LIMIT or VOUT_UV_WARN_LIMIT register.
 201 inX_max                 Maximum voltage.
 202                         From VIN_OV_WARN_LIMIT or VOUT_OV_WARN_LIMIT register.
 203 inX_lcrit               Critical minimum Voltage.
 204                         From VIN_UV_FAULT_LIMIT or VOUT_UV_FAULT_LIMIT register.
 205 inX_crit                Critical maximum voltage.
 206                         From VIN_OV_FAULT_LIMIT or VOUT_OV_FAULT_LIMIT register.
 207 inX_min_alarm           Voltage low alarm. From VOLTAGE_UV_WARNING status.
 208 inX_max_alarm           Voltage high alarm. From VOLTAGE_OV_WARNING status.
 209 inX_lcrit_alarm         Voltage critical low alarm.
 210                         From VOLTAGE_UV_FAULT status.
 211 inX_crit_alarm          Voltage critical high alarm.
 212                         From VOLTAGE_OV_FAULT status.
 213 inX_label               "vin", "vcap", or "voutY"
 214
 215 currX_input             Measured current. From READ_IIN or READ_IOUT register.
 216 currX_max               Maximum current.
 217                         From IIN_OC_WARN_LIMIT or IOUT_OC_WARN_LIMIT register.
 218 currX_lcrit             Critical minimum output current.
 219                         From IOUT_UC_FAULT_LIMIT register.
 220 currX_crit              Critical maximum current.
 221                         From IIN_OC_FAULT_LIMIT or IOUT_OC_FAULT_LIMIT register.
 222 currX_alarm             Current high alarm.
 223                         From IIN_OC_WARNING or IOUT_OC_WARNING status.
 224 currX_max_alarm         Current high alarm.
 225                         From IIN_OC_WARN_LIMIT or IOUT_OC_WARN_LIMIT status.
 226 currX_lcrit_alarm       Output current critical low alarm.
 227                         From IOUT_UC_FAULT status.
 228 currX_crit_alarm        Current critical high alarm.
 229                         From IIN_OC_FAULT or IOUT_OC_FAULT status.
 230 currX_label             "iin" or "ioutY"
 231
 232 powerX_input            Measured power. From READ_PIN or READ_POUT register.
 233 powerX_cap              Output power cap. From POUT_MAX register.
 234 powerX_max              Power limit. From PIN_OP_WARN_LIMIT or
 235                         POUT_OP_WARN_LIMIT register.
 236 powerX_crit             Critical output power limit.
 237                         From POUT_OP_FAULT_LIMIT register.
 238 powerX_alarm            Power high alarm.
 239                         From PIN_OP_WARNING or POUT_OP_WARNING status.
 240 powerX_crit_alarm       Output power critical high alarm.
 241                         From POUT_OP_FAULT status.
 242 powerX_label            "pin" or "poutY"
 243
 244 tempX_input             Measured temperature.
 245                         From READ_TEMPERATURE_X register.
 246 tempX_min               Mimimum temperature. From UT_WARN_LIMIT register.
 247 tempX_max               Maximum temperature. From OT_WARN_LIMIT register.
 248 tempX_lcrit             Critical low temperature.
 249                         From UT_FAULT_LIMIT register.
 250 tempX_crit              Critical high temperature.
 251                         From OT_FAULT_LIMIT register.
 252 tempX_min_alarm         Chip temperature low alarm. Set by comparing
 253                         READ_TEMPERATURE_X with UT_WARN_LIMIT if
 254                         TEMP_UT_WARNING status is set.
 255 tempX_max_alarm         Chip temperature high alarm. Set by comparing
 256                         READ_TEMPERATURE_X with OT_WARN_LIMIT if
 257                         TEMP_OT_WARNING status is set.
 258 tempX_lcrit_alarm       Chip temperature critical low alarm. Set by comparing
 259                         READ_TEMPERATURE_X with UT_FAULT_LIMIT if
 260                         TEMP_UT_FAULT status is set.
 261 tempX_crit_alarm        Chip temperature critical high alarm. Set by comparing
 262                         READ_TEMPERATURE_X with OT_FAULT_LIMIT if
 263                         TEMP_OT_FAULT status is set.
 264 ======================= ========================================================