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31#include <linux/kernel.h>
32#include <linux/module.h>
33#include <linux/init.h>
34#include <linux/err.h>
35#include <linux/slab.h>
36#include <linux/i2c.h>
37#include <linux/hwmon.h>
38#include <linux/hwmon-sysfs.h>
39#include <linux/jiffies.h>
40
41
42#define LTC4151_SENSE_H 0x00
43#define LTC4151_SENSE_L 0x01
44#define LTC4151_VIN_H 0x02
45#define LTC4151_VIN_L 0x03
46#define LTC4151_ADIN_H 0x04
47#define LTC4151_ADIN_L 0x05
48
49struct ltc4151_data {
50 struct device *hwmon_dev;
51
52 struct mutex update_lock;
53 bool valid;
54 unsigned long last_updated;
55
56
57 u8 regs[6];
58};
59
60static struct ltc4151_data *ltc4151_update_device(struct device *dev)
61{
62 struct i2c_client *client = to_i2c_client(dev);
63 struct ltc4151_data *data = i2c_get_clientdata(client);
64 struct ltc4151_data *ret = data;
65
66 mutex_lock(&data->update_lock);
67
68
69
70
71
72 if (time_after(jiffies, data->last_updated + HZ / 6) || !data->valid) {
73 int i;
74
75 dev_dbg(&client->dev, "Starting ltc4151 update\n");
76
77
78 for (i = 0; i < ARRAY_SIZE(data->regs); i++) {
79 int val;
80
81 val = i2c_smbus_read_byte_data(client, i);
82 if (unlikely(val < 0)) {
83 dev_dbg(dev,
84 "Failed to read ADC value: error %d\n",
85 val);
86 ret = ERR_PTR(val);
87 goto abort;
88 }
89 data->regs[i] = val;
90 }
91 data->last_updated = jiffies;
92 data->valid = 1;
93 }
94abort:
95 mutex_unlock(&data->update_lock);
96 return ret;
97}
98
99
100static int ltc4151_get_value(struct ltc4151_data *data, u8 reg)
101{
102 u32 val;
103
104 val = (data->regs[reg] << 4) + (data->regs[reg + 1] >> 4);
105
106 switch (reg) {
107 case LTC4151_ADIN_H:
108
109 val = val * 500 / 1000;
110 break;
111 case LTC4151_SENSE_H:
112
113
114
115
116 val = val * 20;
117 break;
118 case LTC4151_VIN_H:
119
120 val = val * 25;
121 break;
122 default:
123
124 WARN_ON_ONCE(1);
125 val = 0;
126 break;
127 }
128
129 return val;
130}
131
132static ssize_t ltc4151_show_value(struct device *dev,
133 struct device_attribute *da, char *buf)
134{
135 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
136 struct ltc4151_data *data = ltc4151_update_device(dev);
137 int value;
138
139 if (IS_ERR(data))
140 return PTR_ERR(data);
141
142 value = ltc4151_get_value(data, attr->index);
143 return snprintf(buf, PAGE_SIZE, "%d\n", value);
144}
145
146
147
148
149static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4151_show_value, NULL,
150 LTC4151_VIN_H);
151static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4151_show_value, NULL,
152 LTC4151_ADIN_H);
153
154
155static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4151_show_value, NULL,
156 LTC4151_SENSE_H);
157
158
159
160
161
162static struct attribute *ltc4151_attributes[] = {
163 &sensor_dev_attr_in1_input.dev_attr.attr,
164 &sensor_dev_attr_in2_input.dev_attr.attr,
165
166 &sensor_dev_attr_curr1_input.dev_attr.attr,
167
168 NULL,
169};
170
171static const struct attribute_group ltc4151_group = {
172 .attrs = ltc4151_attributes,
173};
174
175static int ltc4151_probe(struct i2c_client *client,
176 const struct i2c_device_id *id)
177{
178 struct i2c_adapter *adapter = client->adapter;
179 struct ltc4151_data *data;
180 int ret;
181
182 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
183 return -ENODEV;
184
185 data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
186 if (!data)
187 return -ENOMEM;
188
189 i2c_set_clientdata(client, data);
190 mutex_init(&data->update_lock);
191
192
193 ret = sysfs_create_group(&client->dev.kobj, <c4151_group);
194 if (ret)
195 return ret;
196
197 data->hwmon_dev = hwmon_device_register(&client->dev);
198 if (IS_ERR(data->hwmon_dev)) {
199 ret = PTR_ERR(data->hwmon_dev);
200 goto out_hwmon_device_register;
201 }
202
203 return 0;
204
205out_hwmon_device_register:
206 sysfs_remove_group(&client->dev.kobj, <c4151_group);
207 return ret;
208}
209
210static int ltc4151_remove(struct i2c_client *client)
211{
212 struct ltc4151_data *data = i2c_get_clientdata(client);
213
214 hwmon_device_unregister(data->hwmon_dev);
215 sysfs_remove_group(&client->dev.kobj, <c4151_group);
216
217 return 0;
218}
219
220static const struct i2c_device_id ltc4151_id[] = {
221 { "ltc4151", 0 },
222 { }
223};
224MODULE_DEVICE_TABLE(i2c, ltc4151_id);
225
226
227static struct i2c_driver ltc4151_driver = {
228 .driver = {
229 .name = "ltc4151",
230 },
231 .probe = ltc4151_probe,
232 .remove = ltc4151_remove,
233 .id_table = ltc4151_id,
234};
235
236module_i2c_driver(ltc4151_driver);
237
238MODULE_AUTHOR("Per Dalen <per.dalen@appeartv.com>");
239MODULE_DESCRIPTION("LTC4151 driver");
240MODULE_LICENSE("GPL");
241