xref: /openbmc/linux/Documentation/hwmon/pmbus.rst (revision 70a59dd8) 
1Kernel driver pmbus
2===================
3
4Supported 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	https://www.onsemi.com/pub_link/Collateral/ADP4000-D.PDF
25
26	https://www.onsemi.com/pub_link/Collateral/NCP4200-D.PDF
27
28	https://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	https://www.ti.com/lit/gpn/tps40400
57
58	https://www.ti.com/lit/gpn/tps544b20
59
60	https://www.ti.com/lit/gpn/tps544b25
61
62	https://www.ti.com/lit/gpn/tps544c20
63
64	https://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
85Author: Guenter Roeck <linux@roeck-us.net>
86
87
88Description
89-----------
90
91This driver supports hardware monitoring for various PMBus compliant devices.
92It supports voltage, current, power, and temperature sensors as supported
93by the device.
94
95Each monitored channel has its own high and low limits, plus a critical
96limit.
97
98Fan support will be added in a later version of this driver.
99
100
101Usage Notes
102-----------
103
104This driver does not probe for PMBus devices, since there is no register
105which can be safely used to identify the chip (The MFG_ID register is not
106supported by all chips), and since there is no well defined address range for
107PMBus devices. You will have to instantiate the devices explicitly.
108
109Example: the following will load the driver for an LTC2978 at address 0x60
110on I2C bus #1::
111
112	$ modprobe pmbus
113	$ echo ltc2978 0x60 > /sys/bus/i2c/devices/i2c-1/new_device
114
115
116Platform data support
117---------------------
118
119Support for additional PMBus chips can be added by defining chip parameters in
120a new chip specific driver file. For example, (untested) code to add support for
121Emerson 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  {
148	return pmbus_do_probe(client, &ds1200_info);
149  }
150
151  static int ds1200_remove(struct i2c_client *client)
152  {
153	return pmbus_do_remove(client);
154  }
155
156  static const struct i2c_device_id ds1200_id[] = {
157	{"ds1200", 0},
158	{}
159  };
160
161  MODULE_DEVICE_TABLE(i2c, ds1200_id);
162
163  /* This is the driver that will be inserted */
164  static struct i2c_driver ds1200_driver = {
165	.driver = {
166		   .name = "ds1200",
167		   },
168	.probe_new = ds1200_probe,
169	.remove = ds1200_remove,
170	.id_table = ds1200_id,
171  };
172
173  static int __init ds1200_init(void)
174  {
175	return i2c_add_driver(&ds1200_driver);
176  }
177
178  static void __exit ds1200_exit(void)
179  {
180	i2c_del_driver(&ds1200_driver);
181  }
182
183
184Sysfs entries
185-------------
186
187When probing the chip, the driver identifies which PMBus registers are
188supported, and determines available sensors from this information.
189Attribute files only exist if respective sensors are supported by the chip.
190Labels are provided to inform the user about the sensor associated with
191a given sysfs entry.
192
193The following attributes are supported. Limits are read-write; all other
194attributes are read-only.
195
196======================= ========================================================
197inX_input		Measured voltage. From READ_VIN or READ_VOUT register.
198inX_min			Minimum Voltage.
199			From VIN_UV_WARN_LIMIT or VOUT_UV_WARN_LIMIT register.
200inX_max			Maximum voltage.
201			From VIN_OV_WARN_LIMIT or VOUT_OV_WARN_LIMIT register.
202inX_lcrit		Critical minimum Voltage.
203			From VIN_UV_FAULT_LIMIT or VOUT_UV_FAULT_LIMIT register.
204inX_crit		Critical maximum voltage.
205			From VIN_OV_FAULT_LIMIT or VOUT_OV_FAULT_LIMIT register.
206inX_min_alarm		Voltage low alarm. From VOLTAGE_UV_WARNING status.
207inX_max_alarm		Voltage high alarm. From VOLTAGE_OV_WARNING status.
208inX_lcrit_alarm		Voltage critical low alarm.
209			From VOLTAGE_UV_FAULT status.
210inX_crit_alarm		Voltage critical high alarm.
211			From VOLTAGE_OV_FAULT status.
212inX_label		"vin", "vcap", or "voutY"
213inX_rated_min		Minimum rated voltage.
214			From MFR_VIN_MIN or MFR_VOUT_MIN register.
215inX_rated_max		Maximum rated voltage.
216			From MFR_VIN_MAX or MFR_VOUT_MAX register.
217
218currX_input		Measured current. From READ_IIN or READ_IOUT register.
219currX_max		Maximum current.
220			From IIN_OC_WARN_LIMIT or IOUT_OC_WARN_LIMIT register.
221currX_lcrit		Critical minimum output current.
222			From IOUT_UC_FAULT_LIMIT register.
223currX_crit		Critical maximum current.
224			From IIN_OC_FAULT_LIMIT or IOUT_OC_FAULT_LIMIT register.
225currX_alarm		Current high alarm.
226			From IIN_OC_WARNING or IOUT_OC_WARNING status.
227currX_max_alarm		Current high alarm.
228			From IIN_OC_WARN_LIMIT or IOUT_OC_WARN_LIMIT status.
229currX_lcrit_alarm	Output current critical low alarm.
230			From IOUT_UC_FAULT status.
231currX_crit_alarm	Current critical high alarm.
232			From IIN_OC_FAULT or IOUT_OC_FAULT status.
233currX_label		"iin", "iinY", "iinY.Z", "ioutY", or "ioutY.Z",
234			where Y reflects the page number and Z reflects the
235			phase.
236currX_rated_max		Maximum rated current.
237			From MFR_IIN_MAX or MFR_IOUT_MAX register.
238
239powerX_input		Measured power. From READ_PIN or READ_POUT register.
240powerX_cap		Output power cap. From POUT_MAX register.
241powerX_max		Power limit. From PIN_OP_WARN_LIMIT or
242			POUT_OP_WARN_LIMIT register.
243powerX_crit		Critical output power limit.
244			From POUT_OP_FAULT_LIMIT register.
245powerX_alarm		Power high alarm.
246			From PIN_OP_WARNING or POUT_OP_WARNING status.
247powerX_crit_alarm	Output power critical high alarm.
248			From POUT_OP_FAULT status.
249powerX_label		"pin", "pinY", "pinY.Z", "poutY", or "poutY.Z",
250			where Y reflects the page number and Z reflects the
251			phase.
252powerX_rated_max	Maximum rated power.
253			From MFR_PIN_MAX or MFR_POUT_MAX register.
254
255tempX_input		Measured temperature.
256			From READ_TEMPERATURE_X register.
257tempX_min		Minimum temperature. From UT_WARN_LIMIT register.
258tempX_max		Maximum temperature. From OT_WARN_LIMIT register.
259tempX_lcrit		Critical low temperature.
260			From UT_FAULT_LIMIT register.
261tempX_crit		Critical high temperature.
262			From OT_FAULT_LIMIT register.
263tempX_min_alarm		Chip temperature low alarm. Set by comparing
264			READ_TEMPERATURE_X with UT_WARN_LIMIT if
265			TEMP_UT_WARNING status is set.
266tempX_max_alarm		Chip temperature high alarm. Set by comparing
267			READ_TEMPERATURE_X with OT_WARN_LIMIT if
268			TEMP_OT_WARNING status is set.
269tempX_lcrit_alarm	Chip temperature critical low alarm. Set by comparing
270			READ_TEMPERATURE_X with UT_FAULT_LIMIT if
271			TEMP_UT_FAULT status is set.
272tempX_crit_alarm	Chip temperature critical high alarm. Set by comparing
273			READ_TEMPERATURE_X with OT_FAULT_LIMIT if
274			TEMP_OT_FAULT status is set.
275tempX_rated_min		Minimum rated temperature.
276			From MFR_TAMBIENT_MIN register.
277tempX_rated_max		Maximum rated temperature.
278			From MFR_TAMBIENT_MAX, MFR_MAX_TEMP_1, MFR_MAX_TEMP_2 or
279			MFR_MAX_TEMP_3 register.
280======================= ========================================================
281