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