1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Driver for Linear Technology LTC4222 Dual Hot Swap controller
4 *
5 * Copyright (c) 2014 Guenter Roeck
6 */
7
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>
18
19/* chip registers */
20
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
36
37/*
38 * Fault register bits
39 */
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)
45
46/* Return the voltage from the given register in mV or mA */
47static int ltc4222_get_value(struct device *dev, u8 reg)
48{
49	struct regmap *regmap = dev_get_drvdata(dev);
50	unsigned int val;
51	u8 buf[2];
52	int ret;
53
54	ret = regmap_bulk_read(regmap, reg, buf, 2);
55	if (ret < 0)
56		return ret;
57
58	val = ((buf[0] << 8) + buf[1]) >> 6;
59
60	switch (reg) {
61	case LTC4222_ADIN1:
62	case LTC4222_ADIN2:
63		/* 1.25 mV resolution. Convert to mV. */
64		val = DIV_ROUND_CLOSEST(val * 5, 4);
65		break;
66	case LTC4222_SOURCE1:
67	case LTC4222_SOURCE2:
68		/* 31.25 mV resolution. Convert to mV. */
69		val = DIV_ROUND_CLOSEST(val * 125, 4);
70		break;
71	case LTC4222_SENSE1:
72	case LTC4222_SENSE2:
73		/*
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
78		 * in mOhm.
79		 */
80		val = DIV_ROUND_CLOSEST(val * 125, 2);
81		break;
82	default:
83		return -EINVAL;
84	}
85	return val;
86}
87
88static ssize_t ltc4222_value_show(struct device *dev,
89				  struct device_attribute *da, char *buf)
90{
91	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
92	int value;
93
94	value = ltc4222_get_value(dev, attr->index);
95	if (value < 0)
96		return value;
97	return sysfs_emit(buf, "%d\n", value);
98}
99
100static ssize_t ltc4222_bool_show(struct device *dev,
101				 struct device_attribute *da, char *buf)
102{
103	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da);
104	struct regmap *regmap = dev_get_drvdata(dev);
105	unsigned int fault;
106	int ret;
107
108	ret = regmap_read(regmap, attr->nr, &fault);
109	if (ret < 0)
110		return ret;
111	fault &= attr->index;
112	if (fault)		/* Clear reported faults in chip register */
113		regmap_update_bits(regmap, attr->nr, attr->index, 0);
114
115	return sysfs_emit(buf, "%d\n", !!fault);
116}
117
118/* Voltages */
119static SENSOR_DEVICE_ATTR_RO(in1_input, ltc4222_value, LTC4222_SOURCE1);
120static SENSOR_DEVICE_ATTR_RO(in2_input, ltc4222_value, LTC4222_ADIN1);
121static SENSOR_DEVICE_ATTR_RO(in3_input, ltc4222_value, LTC4222_SOURCE2);
122static SENSOR_DEVICE_ATTR_RO(in4_input, ltc4222_value, LTC4222_ADIN2);
123
124/*
125 * Voltage alarms
126 * UV/OV faults are associated with the input voltage, and power bad and fet
127 * faults are associated with the output voltage.
128 */
129static SENSOR_DEVICE_ATTR_2_RO(in1_min_alarm, ltc4222_bool, LTC4222_FAULT1,
130			       FAULT_UV);
131static SENSOR_DEVICE_ATTR_2_RO(in1_max_alarm, ltc4222_bool, LTC4222_FAULT1,
132			       FAULT_OV);
133static SENSOR_DEVICE_ATTR_2_RO(in2_alarm, ltc4222_bool, LTC4222_FAULT1,
134			       FAULT_POWER_BAD | FAULT_FET_BAD);
135
136static SENSOR_DEVICE_ATTR_2_RO(in3_min_alarm, ltc4222_bool, LTC4222_FAULT2,
137			       FAULT_UV);
138static SENSOR_DEVICE_ATTR_2_RO(in3_max_alarm, ltc4222_bool, LTC4222_FAULT2,
139			       FAULT_OV);
140static SENSOR_DEVICE_ATTR_2_RO(in4_alarm, ltc4222_bool, LTC4222_FAULT2,
141			       FAULT_POWER_BAD | FAULT_FET_BAD);
142
143/* Current (via sense resistor) */
144static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc4222_value, LTC4222_SENSE1);
145static SENSOR_DEVICE_ATTR_RO(curr2_input, ltc4222_value, LTC4222_SENSE2);
146
147/* Overcurrent alarm */
148static SENSOR_DEVICE_ATTR_2_RO(curr1_max_alarm, ltc4222_bool, LTC4222_FAULT1,
149			       FAULT_OC);
150static SENSOR_DEVICE_ATTR_2_RO(curr2_max_alarm, ltc4222_bool, LTC4222_FAULT2,
151			       FAULT_OC);
152
153static 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,
164
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,
169
170	NULL,
171};
172ATTRIBUTE_GROUPS(ltc4222);
173
174static const struct regmap_config ltc4222_regmap_config = {
175	.reg_bits = 8,
176	.val_bits = 8,
177	.max_register = LTC4222_ADC_CONTROL,
178};
179
180static int ltc4222_probe(struct i2c_client *client)
181{
182	struct device *dev = &client->dev;
183	struct device *hwmon_dev;
184	struct regmap *regmap;
185
186	regmap = devm_regmap_init_i2c(client, &ltc4222_regmap_config);
187	if (IS_ERR(regmap)) {
188		dev_err(dev, "failed to allocate register map\n");
189		return PTR_ERR(regmap);
190	}
191
192	/* Clear faults */
193	regmap_write(regmap, LTC4222_FAULT1, 0x00);
194	regmap_write(regmap, LTC4222_FAULT2, 0x00);
195
196	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
197							   regmap,
198							   ltc4222_groups);
199	return PTR_ERR_OR_ZERO(hwmon_dev);
200}
201
202static const struct i2c_device_id ltc4222_id[] = {
203	{"ltc4222"},
204	{ }
205};
206
207MODULE_DEVICE_TABLE(i2c, ltc4222_id);
208
209static struct i2c_driver ltc4222_driver = {
210	.driver = {
211		   .name = "ltc4222",
212		   },
213	.probe = ltc4222_probe,
214	.id_table = ltc4222_id,
215};
216
217module_i2c_driver(ltc4222_driver);
218
219MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
220MODULE_DESCRIPTION("LTC4222 driver");
221MODULE_LICENSE("GPL");
222