Commit | Line | Data |
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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
3bcfa9e4 | 2 | /* |
1b9c491d GR |
3 | * g760a - Driver for the Global Mixed-mode Technology Inc. G760A |
4 | * fan speed PWM controller chip | |
5 | * | |
6 | * Copyright (C) 2007 Herbert Valerio Riedel <hvr@gnu.org> | |
7 | * | |
8 | * Complete datasheet is available at GMT's website: | |
9 | * http://www.gmt.com.tw/product/datasheet/EDS-760A.pdf | |
1b9c491d | 10 | */ |
3bcfa9e4 HVR |
11 | |
12 | #include <linux/module.h> | |
13 | #include <linux/init.h> | |
14 | #include <linux/slab.h> | |
15 | #include <linux/jiffies.h> | |
16 | #include <linux/i2c.h> | |
17 | #include <linux/hwmon.h> | |
18 | #include <linux/hwmon-sysfs.h> | |
19 | #include <linux/err.h> | |
20 | #include <linux/mutex.h> | |
21 | #include <linux/sysfs.h> | |
22 | ||
3bcfa9e4 HVR |
23 | enum g760a_regs { |
24 | G760A_REG_SET_CNT = 0x00, | |
25 | G760A_REG_ACT_CNT = 0x01, | |
26 | G760A_REG_FAN_STA = 0x02 | |
27 | }; | |
28 | ||
29 | #define G760A_REG_FAN_STA_RPM_OFF 0x1 /* +/-20% off */ | |
30 | #define G760A_REG_FAN_STA_RPM_LOW 0x2 /* below 1920rpm */ | |
31 | ||
32 | /* register data is read (and cached) at most once per second */ | |
33 | #define G760A_UPDATE_INTERVAL (HZ) | |
34 | ||
35 | struct g760a_data { | |
36 | struct i2c_client *client; | |
3bcfa9e4 HVR |
37 | struct mutex update_lock; |
38 | ||
39 | /* board specific parameters */ | |
40 | u32 clk; /* default 32kHz */ | |
41 | u16 fan_div; /* default P=2 */ | |
42 | ||
43 | /* g760a register cache */ | |
44 | unsigned int valid:1; | |
45 | unsigned long last_updated; /* In jiffies */ | |
46 | ||
47 | u8 set_cnt; /* PWM (period) count number; 0xff stops fan */ | |
48 | u8 act_cnt; /* formula: cnt = (CLK * 30)/(rpm * P) */ | |
49 | u8 fan_sta; /* bit 0: set when actual fan speed more than 20% | |
50 | * outside requested fan speed | |
1b9c491d GR |
51 | * bit 1: set when fan speed below 1920 rpm |
52 | */ | |
3bcfa9e4 HVR |
53 | }; |
54 | ||
55 | #define G760A_DEFAULT_CLK 32768 | |
56 | #define G760A_DEFAULT_FAN_DIV 2 | |
57 | ||
58 | #define PWM_FROM_CNT(cnt) (0xff-(cnt)) | |
59 | #define PWM_TO_CNT(pwm) (0xff-(pwm)) | |
60 | ||
ebec05bd | 61 | static inline unsigned int rpm_from_cnt(u8 val, u32 clk, u16 div) |
3bcfa9e4 HVR |
62 | { |
63 | return ((val == 0x00) ? 0 : ((clk*30)/(val*div))); | |
64 | } | |
65 | ||
3bcfa9e4 HVR |
66 | /* read/write wrappers */ |
67 | static int g760a_read_value(struct i2c_client *client, enum g760a_regs reg) | |
68 | { | |
69 | return i2c_smbus_read_byte_data(client, reg); | |
70 | } | |
71 | ||
72 | static int g760a_write_value(struct i2c_client *client, enum g760a_regs reg, | |
73 | u16 value) | |
74 | { | |
75 | return i2c_smbus_write_byte_data(client, reg, value); | |
76 | } | |
77 | ||
1b9c491d | 78 | /* |
3bcfa9e4 HVR |
79 | * sysfs attributes |
80 | */ | |
81 | ||
82 | static struct g760a_data *g760a_update_client(struct device *dev) | |
83 | { | |
e47c39b3 AL |
84 | struct g760a_data *data = dev_get_drvdata(dev); |
85 | struct i2c_client *client = data->client; | |
3bcfa9e4 HVR |
86 | |
87 | mutex_lock(&data->update_lock); | |
88 | ||
89 | if (time_after(jiffies, data->last_updated + G760A_UPDATE_INTERVAL) | |
90 | || !data->valid) { | |
91 | dev_dbg(&client->dev, "Starting g760a update\n"); | |
92 | ||
93 | data->set_cnt = g760a_read_value(client, G760A_REG_SET_CNT); | |
94 | data->act_cnt = g760a_read_value(client, G760A_REG_ACT_CNT); | |
95 | data->fan_sta = g760a_read_value(client, G760A_REG_FAN_STA); | |
96 | ||
97 | data->last_updated = jiffies; | |
952a11ca | 98 | data->valid = true; |
3bcfa9e4 HVR |
99 | } |
100 | ||
101 | mutex_unlock(&data->update_lock); | |
102 | ||
103 | return data; | |
104 | } | |
105 | ||
92a4873d JL |
106 | static ssize_t fan1_input_show(struct device *dev, |
107 | struct device_attribute *da, char *buf) | |
3bcfa9e4 HVR |
108 | { |
109 | struct g760a_data *data = g760a_update_client(dev); | |
110 | unsigned int rpm = 0; | |
111 | ||
112 | mutex_lock(&data->update_lock); | |
113 | if (!(data->fan_sta & G760A_REG_FAN_STA_RPM_LOW)) | |
114 | rpm = rpm_from_cnt(data->act_cnt, data->clk, data->fan_div); | |
115 | mutex_unlock(&data->update_lock); | |
116 | ||
117 | return sprintf(buf, "%d\n", rpm); | |
118 | } | |
119 | ||
92a4873d JL |
120 | static ssize_t fan1_alarm_show(struct device *dev, |
121 | struct device_attribute *da, char *buf) | |
3bcfa9e4 HVR |
122 | { |
123 | struct g760a_data *data = g760a_update_client(dev); | |
124 | ||
125 | int fan_alarm = (data->fan_sta & G760A_REG_FAN_STA_RPM_OFF) ? 1 : 0; | |
126 | ||
127 | return sprintf(buf, "%d\n", fan_alarm); | |
128 | } | |
129 | ||
92a4873d JL |
130 | static ssize_t pwm1_show(struct device *dev, struct device_attribute *da, |
131 | char *buf) | |
3bcfa9e4 HVR |
132 | { |
133 | struct g760a_data *data = g760a_update_client(dev); | |
134 | ||
135 | return sprintf(buf, "%d\n", PWM_FROM_CNT(data->set_cnt)); | |
136 | } | |
137 | ||
92a4873d JL |
138 | static ssize_t pwm1_store(struct device *dev, struct device_attribute *da, |
139 | const char *buf, size_t count) | |
3bcfa9e4 | 140 | { |
3bcfa9e4 | 141 | struct g760a_data *data = g760a_update_client(dev); |
e47c39b3 | 142 | struct i2c_client *client = data->client; |
3bcfa9e4 HVR |
143 | unsigned long val; |
144 | ||
179c4fdb | 145 | if (kstrtoul(buf, 10, &val)) |
3bcfa9e4 HVR |
146 | return -EINVAL; |
147 | ||
148 | mutex_lock(&data->update_lock); | |
2a844c14 | 149 | data->set_cnt = PWM_TO_CNT(clamp_val(val, 0, 255)); |
3bcfa9e4 HVR |
150 | g760a_write_value(client, G760A_REG_SET_CNT, data->set_cnt); |
151 | mutex_unlock(&data->update_lock); | |
152 | ||
153 | return count; | |
154 | } | |
155 | ||
92a4873d JL |
156 | static DEVICE_ATTR_RW(pwm1); |
157 | static DEVICE_ATTR_RO(fan1_input); | |
158 | static DEVICE_ATTR_RO(fan1_alarm); | |
3bcfa9e4 | 159 | |
e47c39b3 | 160 | static struct attribute *g760a_attrs[] = { |
3bcfa9e4 HVR |
161 | &dev_attr_pwm1.attr, |
162 | &dev_attr_fan1_input.attr, | |
163 | &dev_attr_fan1_alarm.attr, | |
164 | NULL | |
165 | }; | |
166 | ||
e47c39b3 | 167 | ATTRIBUTE_GROUPS(g760a); |
3bcfa9e4 | 168 | |
1b9c491d | 169 | /* |
3bcfa9e4 HVR |
170 | * new-style driver model code |
171 | */ | |
172 | ||
67487038 | 173 | static int g760a_probe(struct i2c_client *client) |
3bcfa9e4 | 174 | { |
e47c39b3 | 175 | struct device *dev = &client->dev; |
3bcfa9e4 | 176 | struct g760a_data *data; |
e47c39b3 | 177 | struct device *hwmon_dev; |
3bcfa9e4 | 178 | |
e47c39b3 | 179 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) |
3bcfa9e4 HVR |
180 | return -EIO; |
181 | ||
e47c39b3 | 182 | data = devm_kzalloc(dev, sizeof(struct g760a_data), GFP_KERNEL); |
3bcfa9e4 HVR |
183 | if (!data) |
184 | return -ENOMEM; | |
185 | ||
3bcfa9e4 HVR |
186 | data->client = client; |
187 | mutex_init(&data->update_lock); | |
188 | ||
189 | /* setup default configuration for now */ | |
190 | data->fan_div = G760A_DEFAULT_FAN_DIV; | |
191 | data->clk = G760A_DEFAULT_CLK; | |
192 | ||
e47c39b3 AL |
193 | hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, |
194 | data, | |
195 | g760a_groups); | |
196 | return PTR_ERR_OR_ZERO(hwmon_dev); | |
3bcfa9e4 HVR |
197 | } |
198 | ||
15ac4ddb AL |
199 | static const struct i2c_device_id g760a_id[] = { |
200 | { "g760a", 0 }, | |
201 | { } | |
202 | }; | |
203 | MODULE_DEVICE_TABLE(i2c, g760a_id); | |
204 | ||
205 | static struct i2c_driver g760a_driver = { | |
206 | .driver = { | |
207 | .name = "g760a", | |
208 | }, | |
1975d167 | 209 | .probe = g760a_probe, |
15ac4ddb AL |
210 | .id_table = g760a_id, |
211 | }; | |
212 | ||
f0967eea | 213 | module_i2c_driver(g760a_driver); |
3bcfa9e4 HVR |
214 | |
215 | MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>"); | |
216 | MODULE_DESCRIPTION("GMT G760A driver"); | |
217 | MODULE_LICENSE("GPL"); |