1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Driver for Linear Technology LTC4222 Dual Hot Swap controller
5 * Copyright (c) 2014 Guenter Roeck
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/err.h>
11 #include <linux/slab.h>
12 #include <linux/bitops.h>
13 #include <linux/i2c.h>
14 #include <linux/hwmon.h>
15 #include <linux/hwmon-sysfs.h>
16 #include <linux/jiffies.h>
17 #include <linux/regmap.h>
21 #define LTC4222_CONTROL1 0xd0
22 #define LTC4222_ALERT1 0xd1
23 #define LTC4222_STATUS1 0xd2
24 #define LTC4222_FAULT1 0xd3
25 #define LTC4222_CONTROL2 0xd4
26 #define LTC4222_ALERT2 0xd5
27 #define LTC4222_STATUS2 0xd6
28 #define LTC4222_FAULT2 0xd7
29 #define LTC4222_SOURCE1 0xd8
30 #define LTC4222_SOURCE2 0xda
31 #define LTC4222_ADIN1 0xdc
32 #define LTC4222_ADIN2 0xde
33 #define LTC4222_SENSE1 0xe0
34 #define LTC4222_SENSE2 0xe2
35 #define LTC4222_ADC_CONTROL 0xe4
40 #define FAULT_OV BIT(0)
41 #define FAULT_UV BIT(1)
42 #define FAULT_OC BIT(2)
43 #define FAULT_POWER_BAD BIT(3)
44 #define FAULT_FET_BAD BIT(5)
46 /* Return the voltage from the given register in mV or mA */
47 static int ltc4222_get_value(struct device
*dev
, u8 reg
)
49 struct regmap
*regmap
= dev_get_drvdata(dev
);
54 ret
= regmap_bulk_read(regmap
, reg
, buf
, 2);
58 val
= ((buf
[0] << 8) + buf
[1]) >> 6;
63 /* 1.25 mV resolution. Convert to mV. */
64 val
= DIV_ROUND_CLOSEST(val
* 5, 4);
68 /* 31.25 mV resolution. Convert to mV. */
69 val
= DIV_ROUND_CLOSEST(val
* 125, 4);
74 * 62.5 uV resolution. Convert to current as measured with
75 * an 1 mOhm sense resistor, in mA. If a different sense
76 * resistor is installed, calculate the actual current by
77 * dividing the reported current by the sense resistor value
80 val
= DIV_ROUND_CLOSEST(val
* 125, 2);
88 static ssize_t
ltc4222_value_show(struct device
*dev
,
89 struct device_attribute
*da
, char *buf
)
91 struct sensor_device_attribute
*attr
= to_sensor_dev_attr(da
);
94 value
= ltc4222_get_value(dev
, attr
->index
);
97 return sysfs_emit(buf
, "%d\n", value
);
100 static ssize_t
ltc4222_bool_show(struct device
*dev
,
101 struct device_attribute
*da
, char *buf
)
103 struct sensor_device_attribute_2
*attr
= to_sensor_dev_attr_2(da
);
104 struct regmap
*regmap
= dev_get_drvdata(dev
);
108 ret
= regmap_read(regmap
, attr
->nr
, &fault
);
111 fault
&= attr
->index
;
112 if (fault
) /* Clear reported faults in chip register */
113 regmap_update_bits(regmap
, attr
->nr
, attr
->index
, 0);
115 return sysfs_emit(buf
, "%d\n", !!fault
);
119 static SENSOR_DEVICE_ATTR_RO(in1_input
, ltc4222_value
, LTC4222_SOURCE1
);
120 static SENSOR_DEVICE_ATTR_RO(in2_input
, ltc4222_value
, LTC4222_ADIN1
);
121 static SENSOR_DEVICE_ATTR_RO(in3_input
, ltc4222_value
, LTC4222_SOURCE2
);
122 static SENSOR_DEVICE_ATTR_RO(in4_input
, ltc4222_value
, LTC4222_ADIN2
);
126 * UV/OV faults are associated with the input voltage, and power bad and fet
127 * faults are associated with the output voltage.
129 static SENSOR_DEVICE_ATTR_2_RO(in1_min_alarm
, ltc4222_bool
, LTC4222_FAULT1
,
131 static SENSOR_DEVICE_ATTR_2_RO(in1_max_alarm
, ltc4222_bool
, LTC4222_FAULT1
,
133 static SENSOR_DEVICE_ATTR_2_RO(in2_alarm
, ltc4222_bool
, LTC4222_FAULT1
,
134 FAULT_POWER_BAD
| FAULT_FET_BAD
);
136 static SENSOR_DEVICE_ATTR_2_RO(in3_min_alarm
, ltc4222_bool
, LTC4222_FAULT2
,
138 static SENSOR_DEVICE_ATTR_2_RO(in3_max_alarm
, ltc4222_bool
, LTC4222_FAULT2
,
140 static SENSOR_DEVICE_ATTR_2_RO(in4_alarm
, ltc4222_bool
, LTC4222_FAULT2
,
141 FAULT_POWER_BAD
| FAULT_FET_BAD
);
143 /* Current (via sense resistor) */
144 static SENSOR_DEVICE_ATTR_RO(curr1_input
, ltc4222_value
, LTC4222_SENSE1
);
145 static SENSOR_DEVICE_ATTR_RO(curr2_input
, ltc4222_value
, LTC4222_SENSE2
);
147 /* Overcurrent alarm */
148 static SENSOR_DEVICE_ATTR_2_RO(curr1_max_alarm
, ltc4222_bool
, LTC4222_FAULT1
,
150 static SENSOR_DEVICE_ATTR_2_RO(curr2_max_alarm
, ltc4222_bool
, LTC4222_FAULT2
,
153 static struct attribute
*ltc4222_attrs
[] = {
154 &sensor_dev_attr_in1_input
.dev_attr
.attr
,
155 &sensor_dev_attr_in1_min_alarm
.dev_attr
.attr
,
156 &sensor_dev_attr_in1_max_alarm
.dev_attr
.attr
,
157 &sensor_dev_attr_in2_input
.dev_attr
.attr
,
158 &sensor_dev_attr_in2_alarm
.dev_attr
.attr
,
159 &sensor_dev_attr_in3_input
.dev_attr
.attr
,
160 &sensor_dev_attr_in3_min_alarm
.dev_attr
.attr
,
161 &sensor_dev_attr_in3_max_alarm
.dev_attr
.attr
,
162 &sensor_dev_attr_in4_input
.dev_attr
.attr
,
163 &sensor_dev_attr_in4_alarm
.dev_attr
.attr
,
165 &sensor_dev_attr_curr1_input
.dev_attr
.attr
,
166 &sensor_dev_attr_curr1_max_alarm
.dev_attr
.attr
,
167 &sensor_dev_attr_curr2_input
.dev_attr
.attr
,
168 &sensor_dev_attr_curr2_max_alarm
.dev_attr
.attr
,
172 ATTRIBUTE_GROUPS(ltc4222
);
174 static const struct regmap_config ltc4222_regmap_config
= {
177 .max_register
= LTC4222_ADC_CONTROL
,
180 static int ltc4222_probe(struct i2c_client
*client
)
182 struct device
*dev
= &client
->dev
;
183 struct device
*hwmon_dev
;
184 struct regmap
*regmap
;
186 regmap
= devm_regmap_init_i2c(client
, <c4222_regmap_config
);
187 if (IS_ERR(regmap
)) {
188 dev_err(dev
, "failed to allocate register map\n");
189 return PTR_ERR(regmap
);
193 regmap_write(regmap
, LTC4222_FAULT1
, 0x00);
194 regmap_write(regmap
, LTC4222_FAULT2
, 0x00);
196 hwmon_dev
= devm_hwmon_device_register_with_groups(dev
, client
->name
,
199 return PTR_ERR_OR_ZERO(hwmon_dev
);
202 static const struct i2c_device_id ltc4222_id
[] = {
207 MODULE_DEVICE_TABLE(i2c
, ltc4222_id
);
209 static struct i2c_driver ltc4222_driver
= {
213 .probe_new
= ltc4222_probe
,
214 .id_table
= ltc4222_id
,
217 module_i2c_driver(ltc4222_driver
);
219 MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
220 MODULE_DESCRIPTION("LTC4222 driver");
221 MODULE_LICENSE("GPL");