Herbert Valerio Riedel | 3bcfa9e | 2009-04-06 19:00:30 -0700 | [diff] [blame] | 1 | /* |
| 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/datasheet/g760a.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 | */ |
| 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 | |
| 27 | static const struct i2c_device_id g760a_id[] = { |
| 28 | { "g760a", 0 }, |
| 29 | { } |
| 30 | }; |
| 31 | MODULE_DEVICE_TABLE(i2c, g760a_id); |
| 32 | |
| 33 | enum g760a_regs { |
| 34 | G760A_REG_SET_CNT = 0x00, |
| 35 | G760A_REG_ACT_CNT = 0x01, |
| 36 | G760A_REG_FAN_STA = 0x02 |
| 37 | }; |
| 38 | |
| 39 | #define G760A_REG_FAN_STA_RPM_OFF 0x1 /* +/-20% off */ |
| 40 | #define G760A_REG_FAN_STA_RPM_LOW 0x2 /* below 1920rpm */ |
| 41 | |
| 42 | /* register data is read (and cached) at most once per second */ |
| 43 | #define G760A_UPDATE_INTERVAL (HZ) |
| 44 | |
| 45 | struct g760a_data { |
| 46 | struct i2c_client *client; |
| 47 | struct device *hwmon_dev; |
| 48 | struct mutex update_lock; |
| 49 | |
| 50 | /* board specific parameters */ |
| 51 | u32 clk; /* default 32kHz */ |
| 52 | u16 fan_div; /* default P=2 */ |
| 53 | |
| 54 | /* g760a register cache */ |
| 55 | unsigned int valid:1; |
| 56 | unsigned long last_updated; /* In jiffies */ |
| 57 | |
| 58 | u8 set_cnt; /* PWM (period) count number; 0xff stops fan */ |
| 59 | u8 act_cnt; /* formula: cnt = (CLK * 30)/(rpm * P) */ |
| 60 | u8 fan_sta; /* bit 0: set when actual fan speed more than 20% |
| 61 | * outside requested fan speed |
| 62 | * bit 1: set when fan speed below 1920 rpm */ |
| 63 | }; |
| 64 | |
| 65 | #define G760A_DEFAULT_CLK 32768 |
| 66 | #define G760A_DEFAULT_FAN_DIV 2 |
| 67 | |
| 68 | #define PWM_FROM_CNT(cnt) (0xff-(cnt)) |
| 69 | #define PWM_TO_CNT(pwm) (0xff-(pwm)) |
| 70 | |
Jean Delvare | ebec05b | 2010-03-05 22:17:22 +0100 | [diff] [blame] | 71 | static inline unsigned int rpm_from_cnt(u8 val, u32 clk, u16 div) |
Herbert Valerio Riedel | 3bcfa9e | 2009-04-06 19:00:30 -0700 | [diff] [blame] | 72 | { |
| 73 | return ((val == 0x00) ? 0 : ((clk*30)/(val*div))); |
| 74 | } |
| 75 | |
| 76 | /* new-style driver model */ |
| 77 | static int g760a_probe(struct i2c_client *client, |
| 78 | const struct i2c_device_id *id); |
| 79 | static int g760a_remove(struct i2c_client *client); |
| 80 | |
| 81 | static struct i2c_driver g760a_driver = { |
| 82 | .driver = { |
| 83 | .name = "g760a", |
| 84 | }, |
| 85 | .probe = g760a_probe, |
| 86 | .remove = g760a_remove, |
| 87 | .id_table = g760a_id, |
| 88 | }; |
| 89 | |
| 90 | /* read/write wrappers */ |
| 91 | static int g760a_read_value(struct i2c_client *client, enum g760a_regs reg) |
| 92 | { |
| 93 | return i2c_smbus_read_byte_data(client, reg); |
| 94 | } |
| 95 | |
| 96 | static int g760a_write_value(struct i2c_client *client, enum g760a_regs reg, |
| 97 | u16 value) |
| 98 | { |
| 99 | return i2c_smbus_write_byte_data(client, reg, value); |
| 100 | } |
| 101 | |
| 102 | /**************************************************************************** |
| 103 | * sysfs attributes |
| 104 | */ |
| 105 | |
| 106 | static struct g760a_data *g760a_update_client(struct device *dev) |
| 107 | { |
| 108 | struct i2c_client *client = to_i2c_client(dev); |
| 109 | struct g760a_data *data = i2c_get_clientdata(client); |
| 110 | |
| 111 | mutex_lock(&data->update_lock); |
| 112 | |
| 113 | if (time_after(jiffies, data->last_updated + G760A_UPDATE_INTERVAL) |
| 114 | || !data->valid) { |
| 115 | dev_dbg(&client->dev, "Starting g760a update\n"); |
| 116 | |
| 117 | data->set_cnt = g760a_read_value(client, G760A_REG_SET_CNT); |
| 118 | data->act_cnt = g760a_read_value(client, G760A_REG_ACT_CNT); |
| 119 | data->fan_sta = g760a_read_value(client, G760A_REG_FAN_STA); |
| 120 | |
| 121 | data->last_updated = jiffies; |
| 122 | data->valid = 1; |
| 123 | } |
| 124 | |
| 125 | mutex_unlock(&data->update_lock); |
| 126 | |
| 127 | return data; |
| 128 | } |
| 129 | |
| 130 | static ssize_t show_fan(struct device *dev, struct device_attribute *da, |
| 131 | char *buf) |
| 132 | { |
| 133 | struct g760a_data *data = g760a_update_client(dev); |
| 134 | unsigned int rpm = 0; |
| 135 | |
| 136 | mutex_lock(&data->update_lock); |
| 137 | if (!(data->fan_sta & G760A_REG_FAN_STA_RPM_LOW)) |
| 138 | rpm = rpm_from_cnt(data->act_cnt, data->clk, data->fan_div); |
| 139 | mutex_unlock(&data->update_lock); |
| 140 | |
| 141 | return sprintf(buf, "%d\n", rpm); |
| 142 | } |
| 143 | |
| 144 | static ssize_t show_fan_alarm(struct device *dev, struct device_attribute *da, |
| 145 | char *buf) |
| 146 | { |
| 147 | struct g760a_data *data = g760a_update_client(dev); |
| 148 | |
| 149 | int fan_alarm = (data->fan_sta & G760A_REG_FAN_STA_RPM_OFF) ? 1 : 0; |
| 150 | |
| 151 | return sprintf(buf, "%d\n", fan_alarm); |
| 152 | } |
| 153 | |
| 154 | static ssize_t get_pwm(struct device *dev, struct device_attribute *da, |
| 155 | char *buf) |
| 156 | { |
| 157 | struct g760a_data *data = g760a_update_client(dev); |
| 158 | |
| 159 | return sprintf(buf, "%d\n", PWM_FROM_CNT(data->set_cnt)); |
| 160 | } |
| 161 | |
| 162 | static ssize_t set_pwm(struct device *dev, struct device_attribute *da, |
| 163 | const char *buf, size_t count) |
| 164 | { |
| 165 | struct i2c_client *client = to_i2c_client(dev); |
| 166 | struct g760a_data *data = g760a_update_client(dev); |
| 167 | unsigned long val; |
| 168 | |
| 169 | if (strict_strtoul(buf, 10, &val)) |
| 170 | return -EINVAL; |
| 171 | |
| 172 | mutex_lock(&data->update_lock); |
| 173 | data->set_cnt = PWM_TO_CNT(SENSORS_LIMIT(val, 0, 255)); |
| 174 | g760a_write_value(client, G760A_REG_SET_CNT, data->set_cnt); |
| 175 | mutex_unlock(&data->update_lock); |
| 176 | |
| 177 | return count; |
| 178 | } |
| 179 | |
| 180 | static DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, get_pwm, set_pwm); |
| 181 | static DEVICE_ATTR(fan1_input, S_IRUGO, show_fan, NULL); |
| 182 | static DEVICE_ATTR(fan1_alarm, S_IRUGO, show_fan_alarm, NULL); |
| 183 | |
| 184 | static struct attribute *g760a_attributes[] = { |
| 185 | &dev_attr_pwm1.attr, |
| 186 | &dev_attr_fan1_input.attr, |
| 187 | &dev_attr_fan1_alarm.attr, |
| 188 | NULL |
| 189 | }; |
| 190 | |
| 191 | static const struct attribute_group g760a_group = { |
| 192 | .attrs = g760a_attributes, |
| 193 | }; |
| 194 | |
| 195 | /**************************************************************************** |
| 196 | * new-style driver model code |
| 197 | */ |
| 198 | |
| 199 | static int g760a_probe(struct i2c_client *client, |
| 200 | const struct i2c_device_id *id) |
| 201 | { |
| 202 | struct g760a_data *data; |
| 203 | int err; |
| 204 | |
| 205 | if (!i2c_check_functionality(client->adapter, |
| 206 | I2C_FUNC_SMBUS_BYTE_DATA)) |
| 207 | return -EIO; |
| 208 | |
| 209 | data = kzalloc(sizeof(struct g760a_data), GFP_KERNEL); |
| 210 | if (!data) |
| 211 | return -ENOMEM; |
| 212 | |
| 213 | i2c_set_clientdata(client, data); |
| 214 | |
| 215 | data->client = client; |
| 216 | mutex_init(&data->update_lock); |
| 217 | |
| 218 | /* setup default configuration for now */ |
| 219 | data->fan_div = G760A_DEFAULT_FAN_DIV; |
| 220 | data->clk = G760A_DEFAULT_CLK; |
| 221 | |
| 222 | /* Register sysfs hooks */ |
| 223 | err = sysfs_create_group(&client->dev.kobj, &g760a_group); |
| 224 | if (err) |
| 225 | goto error_sysfs_create_group; |
| 226 | |
| 227 | data->hwmon_dev = hwmon_device_register(&client->dev); |
| 228 | if (IS_ERR(data->hwmon_dev)) { |
| 229 | err = PTR_ERR(data->hwmon_dev); |
| 230 | goto error_hwmon_device_register; |
| 231 | } |
| 232 | |
| 233 | return 0; |
| 234 | |
| 235 | error_hwmon_device_register: |
| 236 | sysfs_remove_group(&client->dev.kobj, &g760a_group); |
| 237 | error_sysfs_create_group: |
| 238 | kfree(data); |
Herbert Valerio Riedel | 3bcfa9e | 2009-04-06 19:00:30 -0700 | [diff] [blame] | 239 | |
| 240 | return err; |
| 241 | } |
| 242 | |
| 243 | static int g760a_remove(struct i2c_client *client) |
| 244 | { |
| 245 | struct g760a_data *data = i2c_get_clientdata(client); |
| 246 | hwmon_device_unregister(data->hwmon_dev); |
| 247 | sysfs_remove_group(&client->dev.kobj, &g760a_group); |
| 248 | kfree(data); |
Herbert Valerio Riedel | 3bcfa9e | 2009-04-06 19:00:30 -0700 | [diff] [blame] | 249 | |
| 250 | return 0; |
| 251 | } |
| 252 | |
| 253 | /* module management */ |
| 254 | |
| 255 | static int __init g760a_init(void) |
| 256 | { |
| 257 | return i2c_add_driver(&g760a_driver); |
| 258 | } |
| 259 | |
| 260 | static void __exit g760a_exit(void) |
| 261 | { |
| 262 | i2c_del_driver(&g760a_driver); |
| 263 | } |
| 264 | |
| 265 | MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>"); |
| 266 | MODULE_DESCRIPTION("GMT G760A driver"); |
| 267 | MODULE_LICENSE("GPL"); |
| 268 | |
| 269 | module_init(g760a_init); |
| 270 | module_exit(g760a_exit); |