1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
|
/*
g760a - Driver for the Global Mixed-mode Technology Inc. G760A
fan speed PWM controller chip
Copyright (C) 2007 Herbert Valerio Riedel <hvr@gnu.org>
Complete datasheet is available at GMT's website:
http://www.gmt.com.tw/datasheet/g760a.pdf
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/sysfs.h>
static const struct i2c_device_id g760a_id[] = {
{ "g760a", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, g760a_id);
enum g760a_regs {
G760A_REG_SET_CNT = 0x00,
G760A_REG_ACT_CNT = 0x01,
G760A_REG_FAN_STA = 0x02
};
#define G760A_REG_FAN_STA_RPM_OFF 0x1 /* +/-20% off */
#define G760A_REG_FAN_STA_RPM_LOW 0x2 /* below 1920rpm */
/* register data is read (and cached) at most once per second */
#define G760A_UPDATE_INTERVAL (HZ)
struct g760a_data {
struct i2c_client *client;
struct device *hwmon_dev;
struct mutex update_lock;
/* board specific parameters */
u32 clk; /* default 32kHz */
u16 fan_div; /* default P=2 */
/* g760a register cache */
unsigned int valid:1;
unsigned long last_updated; /* In jiffies */
u8 set_cnt; /* PWM (period) count number; 0xff stops fan */
u8 act_cnt; /* formula: cnt = (CLK * 30)/(rpm * P) */
u8 fan_sta; /* bit 0: set when actual fan speed more than 20%
* outside requested fan speed
* bit 1: set when fan speed below 1920 rpm */
};
#define G760A_DEFAULT_CLK 32768
#define G760A_DEFAULT_FAN_DIV 2
#define PWM_FROM_CNT(cnt) (0xff-(cnt))
#define PWM_TO_CNT(pwm) (0xff-(pwm))
unsigned int rpm_from_cnt(u8 val, u32 clk, u16 div)
{
return ((val == 0x00) ? 0 : ((clk*30)/(val*div)));
}
/* new-style driver model */
static int g760a_probe(struct i2c_client *client,
const struct i2c_device_id *id);
static int g760a_remove(struct i2c_client *client);
static struct i2c_driver g760a_driver = {
.driver = {
.name = "g760a",
},
.probe = g760a_probe,
.remove = g760a_remove,
.id_table = g760a_id,
};
/* read/write wrappers */
static int g760a_read_value(struct i2c_client *client, enum g760a_regs reg)
{
return i2c_smbus_read_byte_data(client, reg);
}
static int g760a_write_value(struct i2c_client *client, enum g760a_regs reg,
u16 value)
{
return i2c_smbus_write_byte_data(client, reg, value);
}
/****************************************************************************
* sysfs attributes
*/
static struct g760a_data *g760a_update_client(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct g760a_data *data = i2c_get_clientdata(client);
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + G760A_UPDATE_INTERVAL)
|| !data->valid) {
dev_dbg(&client->dev, "Starting g760a update\n");
data->set_cnt = g760a_read_value(client, G760A_REG_SET_CNT);
data->act_cnt = g760a_read_value(client, G760A_REG_ACT_CNT);
data->fan_sta = g760a_read_value(client, G760A_REG_FAN_STA);
data->last_updated = jiffies;
data->valid = 1;
}
mutex_unlock(&data->update_lock);
return data;
}
static ssize_t show_fan(struct device *dev, struct device_attribute *da,
char *buf)
{
struct g760a_data *data = g760a_update_client(dev);
unsigned int rpm = 0;
mutex_lock(&data->update_lock);
if (!(data->fan_sta & G760A_REG_FAN_STA_RPM_LOW))
rpm = rpm_from_cnt(data->act_cnt, data->clk, data->fan_div);
mutex_unlock(&data->update_lock);
return sprintf(buf, "%d\n", rpm);
}
static ssize_t show_fan_alarm(struct device *dev, struct device_attribute *da,
char *buf)
{
struct g760a_data *data = g760a_update_client(dev);
int fan_alarm = (data->fan_sta & G760A_REG_FAN_STA_RPM_OFF) ? 1 : 0;
return sprintf(buf, "%d\n", fan_alarm);
}
static ssize_t get_pwm(struct device *dev, struct device_attribute *da,
char *buf)
{
struct g760a_data *data = g760a_update_client(dev);
return sprintf(buf, "%d\n", PWM_FROM_CNT(data->set_cnt));
}
static ssize_t set_pwm(struct device *dev, struct device_attribute *da,
const char *buf, size_t count)
{
struct i2c_client *client = to_i2c_client(dev);
struct g760a_data *data = g760a_update_client(dev);
unsigned long val;
if (strict_strtoul(buf, 10, &val))
return -EINVAL;
mutex_lock(&data->update_lock);
data->set_cnt = PWM_TO_CNT(SENSORS_LIMIT(val, 0, 255));
g760a_write_value(client, G760A_REG_SET_CNT, data->set_cnt);
mutex_unlock(&data->update_lock);
return count;
}
static DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, get_pwm, set_pwm);
static DEVICE_ATTR(fan1_input, S_IRUGO, show_fan, NULL);
static DEVICE_ATTR(fan1_alarm, S_IRUGO, show_fan_alarm, NULL);
static struct attribute *g760a_attributes[] = {
&dev_attr_pwm1.attr,
&dev_attr_fan1_input.attr,
&dev_attr_fan1_alarm.attr,
NULL
};
static const struct attribute_group g760a_group = {
.attrs = g760a_attributes,
};
/****************************************************************************
* new-style driver model code
*/
static int g760a_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct g760a_data *data;
int err;
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_BYTE_DATA))
return -EIO;
data = kzalloc(sizeof(struct g760a_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
i2c_set_clientdata(client, data);
data->client = client;
mutex_init(&data->update_lock);
/* setup default configuration for now */
data->fan_div = G760A_DEFAULT_FAN_DIV;
data->clk = G760A_DEFAULT_CLK;
/* Register sysfs hooks */
err = sysfs_create_group(&client->dev.kobj, &g760a_group);
if (err)
goto error_sysfs_create_group;
data->hwmon_dev = hwmon_device_register(&client->dev);
if (IS_ERR(data->hwmon_dev)) {
err = PTR_ERR(data->hwmon_dev);
goto error_hwmon_device_register;
}
return 0;
error_hwmon_device_register:
sysfs_remove_group(&client->dev.kobj, &g760a_group);
error_sysfs_create_group:
kfree(data);
i2c_set_clientdata(client, NULL);
return err;
}
static int g760a_remove(struct i2c_client *client)
{
struct g760a_data *data = i2c_get_clientdata(client);
hwmon_device_unregister(data->hwmon_dev);
sysfs_remove_group(&client->dev.kobj, &g760a_group);
kfree(data);
i2c_set_clientdata(client, NULL);
return 0;
}
/* module management */
static int __init g760a_init(void)
{
return i2c_add_driver(&g760a_driver);
}
static void __exit g760a_exit(void)
{
i2c_del_driver(&g760a_driver);
}
MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
MODULE_DESCRIPTION("GMT G760A driver");
MODULE_LICENSE("GPL");
module_init(g760a_init);
module_exit(g760a_exit);
|
