[deliverable/linux.git] / Documentation / hwmon / pmbus

Kernel driver pmbus
====================

Supported chips:
  * Ericsson BMR45X series
    DC/DC Converter
    Prefixes: 'bmr450', 'bmr451', 'bmr453', 'bmr454'
    Addresses scanned: -
    Datasheet:
 http://archive.ericsson.net/service/internet/picov/get?DocNo=28701-EN/LZT146395
  * Linear Technology LTC2978
    Octal PMBus Power Supply Monitor and Controller
    Prefix: 'ltc2978'
    Addresses scanned: -
    Datasheet: http://cds.linear.com/docs/Datasheet/2978fa.pdf
  * Maxim MAX34440
    PMBus 6-Channel Power-Supply Manager
    Prefixes: 'max34440'
    Addresses scanned: -
    Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX34440.pdf
  * Maxim MAX34441
    PMBus 5-Channel Power-Supply Manager and Intelligent Fan Controller
    Prefixes: 'max34441'
    Addresses scanned: -
    Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX34441.pdf
  * Generic PMBus devices
    Prefix: 'pmbus'
    Addresses scanned: -
    Datasheet: n.a.

Author: Guenter Roeck <guenter.roeck@ericsson.com>


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

This driver supports hardware montoring 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,
			const struct i2c_device_id *id)
{
	return pmbus_do_probe(client, id, &ds1200_info);
}

static int ds1200_remove(struct i2c_client *client)
{
	return pmbus_do_remove(client);
}

static const struct i2c_device_id ds1200_id[] = {
	{"ds1200", 0},
	{}
};

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,
	.remove = ds1200_remove,
	.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 suported 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"

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" or "ioutY"

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" or "poutY"

tempX_input		Measured temperature.
			From READ_TEMPERATURE_X register.
tempX_min		Mimimum 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.
Commit	Line	Data
44f5a408 GR	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
44f5a408 GR	16	* Maxim MAX34440
	17	PMBus 6-Channel Power-Supply Manager
	18	Prefixes: 'max34440'
	19	Addresses scanned: -
	20	Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX34440.pdf
	21	* Maxim MAX34441
	22	PMBus 5-Channel Power-Supply Manager and Intelligent Fan Controller
	23	Prefixes: 'max34441'
	24	Addresses scanned: -
	25	Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX34441.pdf
44f5a408 GR	26	* Generic PMBus devices
	27	Prefix: 'pmbus'
	28	Addresses scanned: -
	29	Datasheet: n.a.
	30
	31	Author: Guenter Roeck <guenter.roeck@ericsson.com>
	32
	33
	34	Description
	35	-----------
	36
	37	This driver supports hardware montoring for various PMBus compliant devices.
	38	It supports voltage, current, power, and temperature sensors as supported
	39	by the device.
	40
	41	Each monitored channel has its own high and low limits, plus a critical
	42	limit.
	43
	44	Fan support will be added in a later version of this driver.
	45
	46
	47	Usage Notes
	48	-----------
	49
	50	This driver does not probe for PMBus devices, since there is no register
	51	which can be safely used to identify the chip (The MFG_ID register is not
	52	supported by all chips), and since there is no well defined address range for
	53	PMBus devices. You will have to instantiate the devices explicitly.
	54
	55	Example: the following will load the driver for an LTC2978 at address 0x60
	56	on I2C bus #1:
	57	$ modprobe pmbus
	58	$ echo ltc2978 0x60 > /sys/bus/i2c/devices/i2c-1/new_device
	59
	60
	61	Platform data support
	62	---------------------
	63
	64	Support for additional PMBus chips can be added by defining chip parameters in
	65	a new chip specific driver file. For example, (untested) code to add support for
	66	Emerson DS1200 power modules might look as follows.
	67
	68	static struct pmbus_driver_info ds1200_info = {
	69	.pages = 1,
	70	/* Note: All other sensors are in linear mode */
	71	.direct[PSC_VOLTAGE_OUT] = true,
	72	.direct[PSC_TEMPERATURE] = true,
	73	.direct[PSC_CURRENT_OUT] = true,
	74	.m[PSC_VOLTAGE_IN] = 1,
	75	.b[PSC_VOLTAGE_IN] = 0,
	76	.R[PSC_VOLTAGE_IN] = 3,
	77	.m[PSC_VOLTAGE_OUT] = 1,
	78	.b[PSC_VOLTAGE_OUT] = 0,
	79	.R[PSC_VOLTAGE_OUT] = 3,
	80	.m[PSC_TEMPERATURE] = 1,
	81	.b[PSC_TEMPERATURE] = 0,
	82	.R[PSC_TEMPERATURE] = 3,
	83	.func[0] = PMBUS_HAVE_VIN \| PMBUS_HAVE_IIN \| PMBUS_HAVE_STATUS_INPUT
	84	\| PMBUS_HAVE_VOUT \| PMBUS_HAVE_STATUS_VOUT
	85	\| PMBUS_HAVE_IOUT \| PMBUS_HAVE_STATUS_IOUT
	86	\| PMBUS_HAVE_PIN \| PMBUS_HAVE_POUT
	87	\| PMBUS_HAVE_TEMP \| PMBUS_HAVE_STATUS_TEMP
	88	\| PMBUS_HAVE_FAN12 \| PMBUS_HAVE_STATUS_FAN12,
	89	};
90
91	static int ds1200_probe(struct i2c_client *client,
92	const struct i2c_device_id *id)
93	{
94	return pmbus_do_probe(client, id, &ds1200_info);
95	}
96
97	static int ds1200_remove(struct i2c_client *client)
98	{
99	return pmbus_do_remove(client);
100	}
101
102	static const struct i2c_device_id ds1200_id[] = {
103	{"ds1200", 0},
104	{}
105	};
106
107	MODULE_DEVICE_TABLE(i2c, ds1200_id);
108
109	/* This is the driver that will be inserted */
110	static struct i2c_driver ds1200_driver = {
111	.driver = {
112	.name = "ds1200",
113	},
114	.probe = ds1200_probe,
115	.remove = ds1200_remove,
116	.id_table = ds1200_id,
117	};
118
119	static int __init ds1200_init(void)
120	{
121	return i2c_add_driver(&ds1200_driver);
122	}
123
124	static void __exit ds1200_exit(void)
125	{
126	i2c_del_driver(&ds1200_driver);
127	}
128
129
130	Sysfs entries
131	-------------
132
133	When probing the chip, the driver identifies which PMBus registers are
134	supported, and determines available sensors from this information.
135	Attribute files only exist if respective sensors are suported by the chip.
136	Labels are provided to inform the user about the sensor associated with
137	a given sysfs entry.
138
139	The following attributes are supported. Limits are read-write; all other
140	attributes are read-only.
141
142	inX_input Measured voltage. From READ_VIN or READ_VOUT register.
25985edc	143	inX_min Minimum Voltage.
44f5a408 GR	144	From VIN_UV_WARN_LIMIT or VOUT_UV_WARN_LIMIT register.
	145	inX_max Maximum voltage.
	146	From VIN_OV_WARN_LIMIT or VOUT_OV_WARN_LIMIT register.
25985edc	147	inX_lcrit Critical minimum Voltage.
44f5a408 GR	148	From VIN_UV_FAULT_LIMIT or VOUT_UV_FAULT_LIMIT register.
	149	inX_crit Critical maximum voltage.
	150	From VIN_OV_FAULT_LIMIT or VOUT_OV_FAULT_LIMIT register.
	151	inX_min_alarm Voltage low alarm. From VOLTAGE_UV_WARNING status.
	152	inX_max_alarm Voltage high alarm. From VOLTAGE_OV_WARNING status.
	153	inX_lcrit_alarm Voltage critical low alarm.
	154	From VOLTAGE_UV_FAULT status.
	155	inX_crit_alarm Voltage critical high alarm.
	156	From VOLTAGE_OV_FAULT status.
	157	inX_label "vin", "vcap", or "voutY"
	158
	159	currX_input Measured current. From READ_IIN or READ_IOUT register.
	160	currX_max Maximum current.
	161	From IIN_OC_WARN_LIMIT or IOUT_OC_WARN_LIMIT register.
25985edc	162	currX_lcrit Critical minimum output current.
44f5a408 GR	163	From IOUT_UC_FAULT_LIMIT register.
	164	currX_crit Critical maximum current.
	165	From IIN_OC_FAULT_LIMIT or IOUT_OC_FAULT_LIMIT register.
	166	currX_alarm Current high alarm.
	167	From IIN_OC_WARNING or IOUT_OC_WARNING status.
180b3d88 GR	168	currX_max_alarm Current high alarm.
180b3d88 GR	169	From IIN_OC_WARN_LIMIT or IOUT_OC_WARN_LIMIT status.
44f5a408 GR	170	currX_lcrit_alarm Output current critical low alarm.
	171	From IOUT_UC_FAULT status.
	172	currX_crit_alarm Current critical high alarm.
	173	From IIN_OC_FAULT or IOUT_OC_FAULT status.
180b3d88	174	currX_label "iin" or "ioutY"
44f5a408 GR	175
	176	powerX_input Measured power. From READ_PIN or READ_POUT register.
	177	powerX_cap Output power cap. From POUT_MAX register.
	178	powerX_max Power limit. From PIN_OP_WARN_LIMIT or
	179	POUT_OP_WARN_LIMIT register.
	180	powerX_crit Critical output power limit.
	181	From POUT_OP_FAULT_LIMIT register.
	182	powerX_alarm Power high alarm.
	183	From PIN_OP_WARNING or POUT_OP_WARNING status.
	184	powerX_crit_alarm Output power critical high alarm.
	185	From POUT_OP_FAULT status.
	186	powerX_label "pin" or "poutY"
	187
180b3d88	188	tempX_input Measured temperature.
44f5a408	189	From READ_TEMPERATURE_X register.
180b3d88 GR	190	tempX_min Mimimum temperature. From UT_WARN_LIMIT register.
	191	tempX_max Maximum temperature. From OT_WARN_LIMIT register.
	192	tempX_lcrit Critical low temperature.
44f5a408	193	From UT_FAULT_LIMIT register.
180b3d88	194	tempX_crit Critical high temperature.
44f5a408 GR	195	From OT_FAULT_LIMIT register.
	196	tempX_min_alarm Chip temperature low alarm. Set by comparing
	197	READ_TEMPERATURE_X with UT_WARN_LIMIT if
	198	TEMP_UT_WARNING status is set.
	199	tempX_max_alarm Chip temperature high alarm. Set by comparing
	200	READ_TEMPERATURE_X with OT_WARN_LIMIT if
	201	TEMP_OT_WARNING status is set.
	202	tempX_lcrit_alarm Chip temperature critical low alarm. Set by comparing
	203	READ_TEMPERATURE_X with UT_FAULT_LIMIT if
	204	TEMP_UT_FAULT status is set.
	205	tempX_crit_alarm Chip temperature critical high alarm. Set by comparing
	206	READ_TEMPERATURE_X with OT_FAULT_LIMIT if
	207	TEMP_OT_FAULT status is set.