Commit | Line | Data |
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3bcfa9e4 | 1 | /* |
1b9c491d GR |
2 | * g760a - Driver for the Global Mixed-mode Technology Inc. G760A |
3 | * fan speed PWM controller chip | |
4 | * | |
5 | * Copyright (C) 2007 Herbert Valerio Riedel <hvr@gnu.org> | |
6 | * | |
7 | * Complete datasheet is available at GMT's website: | |
8 | * http://www.gmt.com.tw/product/datasheet/EDS-760A.pdf | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify | |
11 | * it under the terms of the GNU General Public License as published by | |
12 | * the Free Software Foundation; either version 2 of the License, or | |
13 | * (at your option) any later version. | |
14 | */ | |
3bcfa9e4 HVR |
15 | |
16 | #include <linux/module.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/jiffies.h> | |
20 | #include <linux/i2c.h> | |
21 | #include <linux/hwmon.h> | |
22 | #include <linux/hwmon-sysfs.h> | |
23 | #include <linux/err.h> | |
24 | #include <linux/mutex.h> | |
25 | #include <linux/sysfs.h> | |
26 | ||
3bcfa9e4 HVR |
27 | enum g760a_regs { |
28 | G760A_REG_SET_CNT = 0x00, | |
29 | G760A_REG_ACT_CNT = 0x01, | |
30 | G760A_REG_FAN_STA = 0x02 | |
31 | }; | |
32 | ||
33 | #define G760A_REG_FAN_STA_RPM_OFF 0x1 /* +/-20% off */ | |
34 | #define G760A_REG_FAN_STA_RPM_LOW 0x2 /* below 1920rpm */ | |
35 | ||
36 | /* register data is read (and cached) at most once per second */ | |
37 | #define G760A_UPDATE_INTERVAL (HZ) | |
38 | ||
39 | struct g760a_data { | |
40 | struct i2c_client *client; | |
3bcfa9e4 HVR |
41 | struct mutex update_lock; |
42 | ||
43 | /* board specific parameters */ | |
44 | u32 clk; /* default 32kHz */ | |
45 | u16 fan_div; /* default P=2 */ | |
46 | ||
47 | /* g760a register cache */ | |
48 | unsigned int valid:1; | |
49 | unsigned long last_updated; /* In jiffies */ | |
50 | ||
51 | u8 set_cnt; /* PWM (period) count number; 0xff stops fan */ | |
52 | u8 act_cnt; /* formula: cnt = (CLK * 30)/(rpm * P) */ | |
53 | u8 fan_sta; /* bit 0: set when actual fan speed more than 20% | |
54 | * outside requested fan speed | |
1b9c491d GR |
55 | * bit 1: set when fan speed below 1920 rpm |
56 | */ | |
3bcfa9e4 HVR |
57 | }; |
58 | ||
59 | #define G760A_DEFAULT_CLK 32768 | |
60 | #define G760A_DEFAULT_FAN_DIV 2 | |
61 | ||
62 | #define PWM_FROM_CNT(cnt) (0xff-(cnt)) | |
63 | #define PWM_TO_CNT(pwm) (0xff-(pwm)) | |
64 | ||
ebec05bd | 65 | static inline unsigned int rpm_from_cnt(u8 val, u32 clk, u16 div) |
3bcfa9e4 HVR |
66 | { |
67 | return ((val == 0x00) ? 0 : ((clk*30)/(val*div))); | |
68 | } | |
69 | ||
3bcfa9e4 HVR |
70 | /* read/write wrappers */ |
71 | static int g760a_read_value(struct i2c_client *client, enum g760a_regs reg) | |
72 | { | |
73 | return i2c_smbus_read_byte_data(client, reg); | |
74 | } | |
75 | ||
76 | static int g760a_write_value(struct i2c_client *client, enum g760a_regs reg, | |
77 | u16 value) | |
78 | { | |
79 | return i2c_smbus_write_byte_data(client, reg, value); | |
80 | } | |
81 | ||
1b9c491d | 82 | /* |
3bcfa9e4 HVR |
83 | * sysfs attributes |
84 | */ | |
85 | ||
86 | static struct g760a_data *g760a_update_client(struct device *dev) | |
87 | { | |
e47c39b3 AL |
88 | struct g760a_data *data = dev_get_drvdata(dev); |
89 | struct i2c_client *client = data->client; | |
3bcfa9e4 HVR |
90 | |
91 | mutex_lock(&data->update_lock); | |
92 | ||
93 | if (time_after(jiffies, data->last_updated + G760A_UPDATE_INTERVAL) | |
94 | || !data->valid) { | |
95 | dev_dbg(&client->dev, "Starting g760a update\n"); | |
96 | ||
97 | data->set_cnt = g760a_read_value(client, G760A_REG_SET_CNT); | |
98 | data->act_cnt = g760a_read_value(client, G760A_REG_ACT_CNT); | |
99 | data->fan_sta = g760a_read_value(client, G760A_REG_FAN_STA); | |
100 | ||
101 | data->last_updated = jiffies; | |
102 | data->valid = 1; | |
103 | } | |
104 | ||
105 | mutex_unlock(&data->update_lock); | |
106 | ||
107 | return data; | |
108 | } | |
109 | ||
110 | static ssize_t show_fan(struct device *dev, struct device_attribute *da, | |
111 | char *buf) | |
112 | { | |
113 | struct g760a_data *data = g760a_update_client(dev); | |
114 | unsigned int rpm = 0; | |
115 | ||
116 | mutex_lock(&data->update_lock); | |
117 | if (!(data->fan_sta & G760A_REG_FAN_STA_RPM_LOW)) | |
118 | rpm = rpm_from_cnt(data->act_cnt, data->clk, data->fan_div); | |
119 | mutex_unlock(&data->update_lock); | |
120 | ||
121 | return sprintf(buf, "%d\n", rpm); | |
122 | } | |
123 | ||
124 | static ssize_t show_fan_alarm(struct device *dev, struct device_attribute *da, | |
125 | char *buf) | |
126 | { | |
127 | struct g760a_data *data = g760a_update_client(dev); | |
128 | ||
129 | int fan_alarm = (data->fan_sta & G760A_REG_FAN_STA_RPM_OFF) ? 1 : 0; | |
130 | ||
131 | return sprintf(buf, "%d\n", fan_alarm); | |
132 | } | |
133 | ||
134 | static ssize_t get_pwm(struct device *dev, struct device_attribute *da, | |
135 | char *buf) | |
136 | { | |
137 | struct g760a_data *data = g760a_update_client(dev); | |
138 | ||
139 | return sprintf(buf, "%d\n", PWM_FROM_CNT(data->set_cnt)); | |
140 | } | |
141 | ||
142 | static ssize_t set_pwm(struct device *dev, struct device_attribute *da, | |
143 | const char *buf, size_t count) | |
144 | { | |
3bcfa9e4 | 145 | struct g760a_data *data = g760a_update_client(dev); |
e47c39b3 | 146 | struct i2c_client *client = data->client; |
3bcfa9e4 HVR |
147 | unsigned long val; |
148 | ||
179c4fdb | 149 | if (kstrtoul(buf, 10, &val)) |
3bcfa9e4 HVR |
150 | return -EINVAL; |
151 | ||
152 | mutex_lock(&data->update_lock); | |
2a844c14 | 153 | data->set_cnt = PWM_TO_CNT(clamp_val(val, 0, 255)); |
3bcfa9e4 HVR |
154 | g760a_write_value(client, G760A_REG_SET_CNT, data->set_cnt); |
155 | mutex_unlock(&data->update_lock); | |
156 | ||
157 | return count; | |
158 | } | |
159 | ||
160 | static DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, get_pwm, set_pwm); | |
161 | static DEVICE_ATTR(fan1_input, S_IRUGO, show_fan, NULL); | |
162 | static DEVICE_ATTR(fan1_alarm, S_IRUGO, show_fan_alarm, NULL); | |
163 | ||
e47c39b3 | 164 | static struct attribute *g760a_attrs[] = { |
3bcfa9e4 HVR |
165 | &dev_attr_pwm1.attr, |
166 | &dev_attr_fan1_input.attr, | |
167 | &dev_attr_fan1_alarm.attr, | |
168 | NULL | |
169 | }; | |
170 | ||
e47c39b3 | 171 | ATTRIBUTE_GROUPS(g760a); |
3bcfa9e4 | 172 | |
1b9c491d | 173 | /* |
3bcfa9e4 HVR |
174 | * new-style driver model code |
175 | */ | |
176 | ||
177 | static int g760a_probe(struct i2c_client *client, | |
178 | const struct i2c_device_id *id) | |
179 | { | |
e47c39b3 | 180 | struct device *dev = &client->dev; |
3bcfa9e4 | 181 | struct g760a_data *data; |
e47c39b3 | 182 | struct device *hwmon_dev; |
3bcfa9e4 | 183 | |
e47c39b3 | 184 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) |
3bcfa9e4 HVR |
185 | return -EIO; |
186 | ||
e47c39b3 | 187 | data = devm_kzalloc(dev, sizeof(struct g760a_data), GFP_KERNEL); |
3bcfa9e4 HVR |
188 | if (!data) |
189 | return -ENOMEM; | |
190 | ||
3bcfa9e4 HVR |
191 | data->client = client; |
192 | mutex_init(&data->update_lock); | |
193 | ||
194 | /* setup default configuration for now */ | |
195 | data->fan_div = G760A_DEFAULT_FAN_DIV; | |
196 | data->clk = G760A_DEFAULT_CLK; | |
197 | ||
e47c39b3 AL |
198 | hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, |
199 | data, | |
200 | g760a_groups); | |
201 | return PTR_ERR_OR_ZERO(hwmon_dev); | |
3bcfa9e4 HVR |
202 | } |
203 | ||
15ac4ddb AL |
204 | static const struct i2c_device_id g760a_id[] = { |
205 | { "g760a", 0 }, | |
206 | { } | |
207 | }; | |
208 | MODULE_DEVICE_TABLE(i2c, g760a_id); | |
209 | ||
210 | static struct i2c_driver g760a_driver = { | |
211 | .driver = { | |
212 | .name = "g760a", | |
213 | }, | |
214 | .probe = g760a_probe, | |
15ac4ddb AL |
215 | .id_table = g760a_id, |
216 | }; | |
217 | ||
f0967eea | 218 | module_i2c_driver(g760a_driver); |
3bcfa9e4 HVR |
219 | |
220 | MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>"); | |
221 | MODULE_DESCRIPTION("GMT G760A driver"); | |
222 | MODULE_LICENSE("GPL"); |