tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
hwmon: Driver for Linear Technologies LTC4260
LTC4260 is a Positive Voltage Hot Swap Controller.
The driver currently only supports voltage monitoring, not voltage control.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
+269
+56
Documentation/hwmon/ltc4260
+56
Documentation/hwmon/ltc4260
···
1
+
Kernel driver ltc4260
2
+
=====================
3
+
4
+
Supported chips:
5
+
* Linear Technology LTC4260
6
+
Prefix: 'ltc4260'
7
+
Addresses scanned: -
8
+
Datasheet:
9
+
http://cds.linear.com/docs/en/datasheet/4260fc.pdf
10
+
11
+
Author: Guenter Roeck <linux@roeck-us.net>
12
+
13
+
14
+
Description
15
+
-----------
16
+
17
+
The LTC4260 Hot Swap controller allows a board to be safely inserted
18
+
and removed from a live backplane.
19
+
20
+
21
+
Usage Notes
22
+
-----------
23
+
24
+
This driver does not probe for LTC4260 devices, since there is no register
25
+
which can be safely used to identify the chip. You will have to instantiate
26
+
the devices explicitly.
27
+
28
+
Example: the following will load the driver for an LTC4260 at address 0x10
29
+
on I2C bus #1:
30
+
$ modprobe ltc4260
31
+
$ echo ltc4260 0x10 > /sys/bus/i2c/devices/i2c-1/new_device
32
+
33
+
34
+
Sysfs entries
35
+
-------------
36
+
37
+
Voltage readings provided by this driver are reported as obtained from the ADC
38
+
registers. If a set of voltage divider resistors is installed, calculate the
39
+
real voltage by multiplying the reported value with (R1+R2)/R2, where R1 is the
40
+
value of the divider resistor against the measured voltage and R2 is the value
41
+
of the divider resistor against Ground.
42
+
43
+
Current reading provided by this driver is reported as obtained from the ADC
44
+
Current Sense register. The reported value assumes that a 1 mOhm sense resistor
45
+
is installed. If a different sense resistor is installed, calculate the real
46
+
current by dividing the reported value by the sense resistor value in mOhm.
47
+
48
+
in1_input SOURCE voltage (mV)
49
+
in1_min_alarm Undervoltage alarm
50
+
in1_max_alarm Overvoltage alarm
51
+
52
+
in2_input ADIN voltage (mV)
53
+
in2_alarm Power bad alarm
54
+
55
+
curr1_input SENSE current (mA)
56
+
curr1_alarm SENSE overcurrent alarm
+12
drivers/hwmon/Kconfig
+12
drivers/hwmon/Kconfig
···
821
821
This driver can also be built as a module. If so, the module will
822
822
be called ltc4245.
823
823
824
+
config SENSORS_LTC4260
825
+
tristate "Linear Technology LTC4260"
826
+
depends on I2C
827
+
select REGMAP_I2C
828
+
default n
829
+
help
830
+
If you say yes here you get support for Linear Technology LTC4261
831
+
Positive Voltage Hot Swap Controller I2C interface.
832
+
833
+
This driver can also be built as a module. If so, the module will
834
+
be called ltc4260.
835
+
824
836
config SENSORS_LTC4261
825
837
tristate "Linear Technology LTC4261"
826
838
depends on I2C
+1
drivers/hwmon/Makefile
+1
drivers/hwmon/Makefile
···
99
99
obj-$(CONFIG_SENSORS_LTC4215) += ltc4215.o
100
100
obj-$(CONFIG_SENSORS_LTC4222) += ltc4222.o
101
101
obj-$(CONFIG_SENSORS_LTC4245) += ltc4245.o
102
+
obj-$(CONFIG_SENSORS_LTC4260) += ltc4260.o
102
103
obj-$(CONFIG_SENSORS_LTC4261) += ltc4261.o
103
104
obj-$(CONFIG_SENSORS_MAX1111) += max1111.o
104
105
obj-$(CONFIG_SENSORS_MAX16065) += max16065.o
+200
drivers/hwmon/ltc4260.c
+200
drivers/hwmon/ltc4260.c
···
1
+
/*
2
+
* Driver for Linear Technology LTC4260 I2C Positive Voltage Hot Swap Controller
3
+
*
4
+
* Copyright (c) 2014 Guenter Roeck
5
+
*
6
+
* This program is free software; you can redistribute it and/or modify
7
+
* it under the terms of the GNU General Public License as published by
8
+
* the Free Software Foundation; either version 2 of the License, or
9
+
* (at your option) any later version.
10
+
*
11
+
* This program is distributed in the hope that it will be useful,
12
+
* but WITHOUT ANY WARRANTY; without even the implied warranty of
13
+
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14
+
* GNU General Public License for more details.
15
+
*/
16
+
17
+
#include <linux/kernel.h>
18
+
#include <linux/module.h>
19
+
#include <linux/err.h>
20
+
#include <linux/slab.h>
21
+
#include <linux/i2c.h>
22
+
#include <linux/hwmon.h>
23
+
#include <linux/hwmon-sysfs.h>
24
+
#include <linux/jiffies.h>
25
+
#include <linux/regmap.h>
26
+
27
+
/* chip registers */
28
+
#define LTC4260_CONTROL 0x00
29
+
#define LTC4260_ALERT 0x01
30
+
#define LTC4260_STATUS 0x02
31
+
#define LTC4260_FAULT 0x03
32
+
#define LTC4260_SENSE 0x04
33
+
#define LTC4260_SOURCE 0x05
34
+
#define LTC4260_ADIN 0x06
35
+
36
+
/*
37
+
* Fault register bits
38
+
*/
39
+
#define FAULT_OV (1 << 0)
40
+
#define FAULT_UV (1 << 1)
41
+
#define FAULT_OC (1 << 2)
42
+
#define FAULT_POWER_BAD (1 << 3)
43
+
#define FAULT_FET_SHORT (1 << 5)
44
+
45
+
/* Return the voltage from the given register in mV or mA */
46
+
static int ltc4260_get_value(struct device *dev, u8 reg)
47
+
{
48
+
struct regmap *regmap = dev_get_drvdata(dev);
49
+
unsigned int val;
50
+
int ret;
51
+
52
+
ret = regmap_read(regmap, reg, &val);
53
+
if (ret < 0)
54
+
return ret;
55
+
56
+
switch (reg) {
57
+
case LTC4260_ADIN:
58
+
/* 10 mV resolution. Convert to mV. */
59
+
val = val * 10;
60
+
break;
61
+
case LTC4260_SOURCE:
62
+
/* 400 mV resolution. Convert to mV. */
63
+
val = val * 400;
64
+
break;
65
+
case LTC4260_SENSE:
66
+
/*
67
+
* 300 uV resolution. Convert to current as measured with
68
+
* an 1 mOhm sense resistor, in mA. If a different sense
69
+
* resistor is installed, calculate the actual current by
70
+
* dividing the reported current by the sense resistor value
71
+
* in mOhm.
72
+
*/
73
+
val = val * 300;
74
+
break;
75
+
default:
76
+
return -EINVAL;
77
+
}
78
+
79
+
return val;
80
+
}
81
+
82
+
static ssize_t ltc4260_show_value(struct device *dev,
83
+
struct device_attribute *da, char *buf)
84
+
{
85
+
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
86
+
int value;
87
+
88
+
value = ltc4260_get_value(dev, attr->index);
89
+
if (value < 0)
90
+
return value;
91
+
return snprintf(buf, PAGE_SIZE, "%d\n", value);
92
+
}
93
+
94
+
static ssize_t ltc4260_show_bool(struct device *dev,
95
+
struct device_attribute *da, char *buf)
96
+
{
97
+
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
98
+
struct regmap *regmap = dev_get_drvdata(dev);
99
+
unsigned int fault;
100
+
int ret;
101
+
102
+
ret = regmap_read(regmap, LTC4260_FAULT, &fault);
103
+
if (ret < 0)
104
+
return ret;
105
+
106
+
fault &= attr->index;
107
+
if (fault) /* Clear reported faults in chip register */
108
+
regmap_update_bits(regmap, LTC4260_FAULT, attr->index, 0);
109
+
110
+
return snprintf(buf, PAGE_SIZE, "%d\n", !!fault);
111
+
}
112
+
113
+
/* Voltages */
114
+
static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4260_show_value, NULL,
115
+
LTC4260_SOURCE);
116
+
static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4260_show_value, NULL,
117
+
LTC4260_ADIN);
118
+
119
+
/*
120
+
* Voltage alarms
121
+
* UV/OV faults are associated with the input voltage, and the POWER BAD and
122
+
* FET SHORT faults are associated with the output voltage.
123
+
*/
124
+
static SENSOR_DEVICE_ATTR(in1_min_alarm, S_IRUGO, ltc4260_show_bool, NULL,
125
+
FAULT_UV);
126
+
static SENSOR_DEVICE_ATTR(in1_max_alarm, S_IRUGO, ltc4260_show_bool, NULL,
127
+
FAULT_OV);
128
+
static SENSOR_DEVICE_ATTR(in2_alarm, S_IRUGO, ltc4260_show_bool, NULL,
129
+
FAULT_POWER_BAD | FAULT_FET_SHORT);
130
+
131
+
/* Current (via sense resistor) */
132
+
static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4260_show_value, NULL,
133
+
LTC4260_SENSE);
134
+
135
+
/* Overcurrent alarm */
136
+
static SENSOR_DEVICE_ATTR(curr1_max_alarm, S_IRUGO, ltc4260_show_bool, NULL,
137
+
FAULT_OC);
138
+
139
+
static struct attribute *ltc4260_attrs[] = {
140
+
&sensor_dev_attr_in1_input.dev_attr.attr,
141
+
&sensor_dev_attr_in1_min_alarm.dev_attr.attr,
142
+
&sensor_dev_attr_in1_max_alarm.dev_attr.attr,
143
+
&sensor_dev_attr_in2_input.dev_attr.attr,
144
+
&sensor_dev_attr_in2_alarm.dev_attr.attr,
145
+
146
+
&sensor_dev_attr_curr1_input.dev_attr.attr,
147
+
&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
148
+
149
+
NULL,
150
+
};
151
+
ATTRIBUTE_GROUPS(ltc4260);
152
+
153
+
static struct regmap_config ltc4260_regmap_config = {
154
+
.reg_bits = 8,
155
+
.val_bits = 8,
156
+
.max_register = LTC4260_ADIN,
157
+
};
158
+
159
+
static int ltc4260_probe(struct i2c_client *client,
160
+
const struct i2c_device_id *id)
161
+
{
162
+
struct device *dev = &client->dev;
163
+
struct device *hwmon_dev;
164
+
struct regmap *regmap;
165
+
166
+
regmap = devm_regmap_init_i2c(client, <c4260_regmap_config);
167
+
if (IS_ERR(regmap)) {
168
+
dev_err(dev, "failed to allocate register map\n");
169
+
return PTR_ERR(regmap);
170
+
}
171
+
172
+
/* Clear faults */
173
+
regmap_write(regmap, LTC4260_FAULT, 0x00);
174
+
175
+
hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
176
+
regmap,
177
+
ltc4260_groups);
178
+
return PTR_ERR_OR_ZERO(hwmon_dev);
179
+
}
180
+
181
+
static const struct i2c_device_id ltc4260_id[] = {
182
+
{"ltc4260", 0},
183
+
{ }
184
+
};
185
+
186
+
MODULE_DEVICE_TABLE(i2c, ltc4260_id);
187
+
188
+
static struct i2c_driver ltc4260_driver = {
189
+
.driver = {
190
+
.name = "ltc4260",
191
+
},
192
+
.probe = ltc4260_probe,
193
+
.id_table = ltc4260_id,
194
+
};
195
+
196
+
module_i2c_driver(ltc4260_driver);
197
+
198
+
MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
199
+
MODULE_DESCRIPTION("LTC4260 driver");
200
+
MODULE_LICENSE("GPL");