Documentation / hwmon / pmbus.rst


Based on kernel version 6.11. Page generated on 2024-09-24 08:21 EST.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277
Kernel driver pmbus
===================

Supported chips:

  * Flex BMR310, BMR453, BMR454, BMR456, BMR457, BMR458, BMR480,
    BMR490, BMR491, BMR492

    Prefixes: 'bmr310', 'bmr453', 'bmr454', 'bmr456', 'bmr457', 'bmr458', 'bmr480',
    'bmr490', 'bmr491', 'bmr492'

    Addresses scanned: -

    Datasheets:

	https://flexpowermodules.com/products


  * ON Semiconductor ADP4000, NCP4200, NCP4208

    Prefixes: 'adp4000', 'ncp4200', 'ncp4208'

    Addresses scanned: -

    Datasheets:

	https://www.onsemi.com/pub_link/Collateral/ADP4000-D.PDF

	https://www.onsemi.com/pub_link/Collateral/NCP4200-D.PDF

	https://www.onsemi.com/pub_link/Collateral/JUNE%202009-%20REV.%200.PDF

  * Lineage Power

    Prefixes: 'mdt040', 'pdt003', 'pdt006', 'pdt012', 'udt020'

    Addresses scanned: -

    Datasheets:

	http://www.lineagepower.com/oem/pdf/PDT003A0X.pdf

	http://www.lineagepower.com/oem/pdf/PDT006A0X.pdf

	http://www.lineagepower.com/oem/pdf/PDT012A0X.pdf

	http://www.lineagepower.com/oem/pdf/UDT020A0X.pdf

	http://www.lineagepower.com/oem/pdf/MDT040A0X.pdf

  * Texas Instruments TPS40400, TPS544B20, TPS544B25, TPS544C20, TPS544C25

    Prefixes: 'tps40400', 'tps544b20', 'tps544b25', 'tps544c20', 'tps544c25'

    Addresses scanned: -

    Datasheets:

	https://www.ti.com/lit/gpn/tps40400

	https://www.ti.com/lit/gpn/tps544b20

	https://www.ti.com/lit/gpn/tps544b25

	https://www.ti.com/lit/gpn/tps544c20

	https://www.ti.com/lit/gpn/tps544c25

  * Maxim MAX20796

    Prefix: 'max20796'

    Addresses scanned: -

    Datasheet:

	Not published

  * Generic PMBus devices

    Prefix: 'pmbus'

    Addresses scanned: -

    Datasheet: n.a.


Author: Guenter Roeck <linux@roeck-us.net>


Description
-----------

This driver supports hardware monitoring 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)
  {
	return pmbus_do_probe(client, &ds1200_info);
  }

  static const struct i2c_device_id ds1200_id[] = {
	{"ds1200"},
	{}
  };

  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,
	.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 supported 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"
inX_rated_min		Minimum rated voltage.
			From MFR_VIN_MIN or MFR_VOUT_MIN register.
inX_rated_max		Maximum rated voltage.
			From MFR_VIN_MAX or MFR_VOUT_MAX register.

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", "iinY", "iinY.Z", "ioutY", or "ioutY.Z",
			where Y reflects the page number and Z reflects the
			phase.
currX_rated_max		Maximum rated current.
			From MFR_IIN_MAX or MFR_IOUT_MAX register.

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", "pinY", "pinY.Z", "poutY", or "poutY.Z",
			where Y reflects the page number and Z reflects the
			phase.
powerX_rated_max	Maximum rated power.
			From MFR_PIN_MAX or MFR_POUT_MAX register.

tempX_input		Measured temperature.
			From READ_TEMPERATURE_X register.
tempX_min		Minimum 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.
tempX_rated_min		Minimum rated temperature.
			From MFR_TAMBIENT_MIN register.
tempX_rated_max		Maximum rated temperature.
			From MFR_TAMBIENT_MAX, MFR_MAX_TEMP_1, MFR_MAX_TEMP_2 or
			MFR_MAX_TEMP_3 register.
======================= ========================================================