1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * lm92 - Hardware monitoring driver 4 * Copyright (C) 2005-2008 Jean Delvare <jdelvare@suse.de> 5 * 6 * Based on the lm90 driver, with some ideas taken from the lm_sensors 7 * lm92 driver as well. 8 * 9 * The LM92 is a sensor chip made by National Semiconductor. It reports 10 * its own temperature with a 0.0625 deg resolution and a 0.33 deg 11 * accuracy. Complete datasheet can be obtained from National's website 12 * at: 13 * http://www.national.com/pf/LM/LM92.html 14 * 15 * This driver also supports the MAX6635 sensor chip made by Maxim. 16 * This chip is compatible with the LM92, but has a lesser accuracy 17 * (1.0 deg). Complete datasheet can be obtained from Maxim's website 18 * at: 19 * http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3074 20 * 21 * Since the LM92 was the first chipset supported by this driver, most 22 * comments will refer to this chipset, but are actually general and 23 * concern all supported chipsets, unless mentioned otherwise. 24 * 25 * Support could easily be added for the National Semiconductor LM76 26 * and Maxim MAX6633 and MAX6634 chips, which are mostly compatible 27 * with the LM92. 28 */ 29 30 #include <linux/err.h> 31 #include <linux/hwmon.h> 32 #include <linux/hwmon-sysfs.h> 33 #include <linux/i2c.h> 34 #include <linux/init.h> 35 #include <linux/jiffies.h> 36 #include <linux/module.h> 37 #include <linux/mutex.h> 38 #include <linux/slab.h> 39 40 /* 41 * The LM92 and MAX6635 have 2 two-state pins for address selection, 42 * resulting in 4 possible addresses. 43 */ 44 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 45 I2C_CLIENT_END }; 46 /* The LM92 registers */ 47 #define LM92_REG_CONFIG 0x01 /* 8-bit, RW */ 48 #define LM92_REG_TEMP 0x00 /* 16-bit, RO */ 49 #define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */ 50 #define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */ 51 #define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */ 52 #define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */ 53 #define LM92_REG_MAN_ID 0x07 /* 16-bit, RO, LM92 only */ 54 55 /* 56 * The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius, 57 * left-justified in 16-bit registers. No rounding is done, with such 58 * a resolution it's just not worth it. Note that the MAX6635 doesn't 59 * make use of the 4 lower bits for limits (i.e. effective resolution 60 * for limits is 1 degree Celsius). 61 */ 62 static inline int TEMP_FROM_REG(s16 reg) 63 { 64 return reg / 8 * 625 / 10; 65 } 66 67 static inline s16 TEMP_TO_REG(long val, int resolution) 68 { 69 val = clamp_val(val, -60000, 160000); 70 return DIV_ROUND_CLOSEST(val << (resolution - 9), 1000) << (16 - resolution); 71 } 72 73 /* Alarm flags are stored in the 3 LSB of the temperature register */ 74 static inline u8 ALARMS_FROM_REG(s16 reg) 75 { 76 return reg & 0x0007; 77 } 78 79 enum temp_index { 80 t_input, 81 t_crit, 82 t_min, 83 t_max, 84 t_hyst, 85 t_num_regs 86 }; 87 88 static const u8 regs[t_num_regs] = { 89 [t_input] = LM92_REG_TEMP, 90 [t_crit] = LM92_REG_TEMP_CRIT, 91 [t_min] = LM92_REG_TEMP_LOW, 92 [t_max] = LM92_REG_TEMP_HIGH, 93 [t_hyst] = LM92_REG_TEMP_HYST, 94 }; 95 96 /* Client data (each client gets its own) */ 97 struct lm92_data { 98 struct i2c_client *client; 99 struct mutex update_lock; 100 int resolution; 101 bool valid; /* false until following fields are valid */ 102 unsigned long last_updated; /* in jiffies */ 103 104 /* registers values */ 105 s16 temp[t_num_regs]; /* index with enum temp_index */ 106 }; 107 108 /* 109 * Sysfs attributes and callback functions 110 */ 111 112 static struct lm92_data *lm92_update_device(struct device *dev) 113 { 114 struct lm92_data *data = dev_get_drvdata(dev); 115 struct i2c_client *client = data->client; 116 int i; 117 118 mutex_lock(&data->update_lock); 119 120 if (time_after(jiffies, data->last_updated + HZ) || 121 !data->valid) { 122 dev_dbg(&client->dev, "Updating lm92 data\n"); 123 for (i = 0; i < t_num_regs; i++) { 124 data->temp[i] = 125 i2c_smbus_read_word_swapped(client, regs[i]); 126 } 127 data->last_updated = jiffies; 128 data->valid = true; 129 } 130 131 mutex_unlock(&data->update_lock); 132 133 return data; 134 } 135 136 static ssize_t temp_show(struct device *dev, struct device_attribute *devattr, 137 char *buf) 138 { 139 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); 140 struct lm92_data *data = lm92_update_device(dev); 141 142 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index])); 143 } 144 145 static ssize_t temp_store(struct device *dev, 146 struct device_attribute *devattr, const char *buf, 147 size_t count) 148 { 149 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); 150 struct lm92_data *data = dev_get_drvdata(dev); 151 struct i2c_client *client = data->client; 152 int nr = attr->index; 153 long val; 154 int err; 155 156 err = kstrtol(buf, 10, &val); 157 if (err) 158 return err; 159 160 mutex_lock(&data->update_lock); 161 data->temp[nr] = TEMP_TO_REG(val, data->resolution); 162 i2c_smbus_write_word_swapped(client, regs[nr], data->temp[nr]); 163 mutex_unlock(&data->update_lock); 164 return count; 165 } 166 167 static ssize_t temp_hyst_show(struct device *dev, 168 struct device_attribute *devattr, char *buf) 169 { 170 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); 171 struct lm92_data *data = lm92_update_device(dev); 172 173 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]) 174 - TEMP_FROM_REG(data->temp[t_hyst])); 175 } 176 177 static ssize_t temp1_min_hyst_show(struct device *dev, 178 struct device_attribute *attr, char *buf) 179 { 180 struct lm92_data *data = lm92_update_device(dev); 181 182 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[t_min]) 183 + TEMP_FROM_REG(data->temp[t_hyst])); 184 } 185 186 static ssize_t temp_hyst_store(struct device *dev, 187 struct device_attribute *devattr, 188 const char *buf, size_t count) 189 { 190 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); 191 struct lm92_data *data = dev_get_drvdata(dev); 192 struct i2c_client *client = data->client; 193 long val; 194 int err; 195 196 err = kstrtol(buf, 10, &val); 197 if (err) 198 return err; 199 200 val = clamp_val(val, -120000, 220000); 201 mutex_lock(&data->update_lock); 202 data->temp[t_hyst] = 203 TEMP_TO_REG(TEMP_FROM_REG(data->temp[attr->index]) - val, 204 data->resolution); 205 i2c_smbus_write_word_swapped(client, LM92_REG_TEMP_HYST, 206 data->temp[t_hyst]); 207 mutex_unlock(&data->update_lock); 208 return count; 209 } 210 211 static ssize_t alarms_show(struct device *dev, struct device_attribute *attr, 212 char *buf) 213 { 214 struct lm92_data *data = lm92_update_device(dev); 215 216 return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp[t_input])); 217 } 218 219 static ssize_t alarm_show(struct device *dev, struct device_attribute *attr, 220 char *buf) 221 { 222 int bitnr = to_sensor_dev_attr(attr)->index; 223 struct lm92_data *data = lm92_update_device(dev); 224 return sprintf(buf, "%d\n", (data->temp[t_input] >> bitnr) & 1); 225 } 226 227 static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, t_input); 228 static SENSOR_DEVICE_ATTR_RW(temp1_crit, temp, t_crit); 229 static SENSOR_DEVICE_ATTR_RW(temp1_crit_hyst, temp_hyst, t_crit); 230 static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, t_min); 231 static DEVICE_ATTR_RO(temp1_min_hyst); 232 static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, t_max); 233 static SENSOR_DEVICE_ATTR_RO(temp1_max_hyst, temp_hyst, t_max); 234 static DEVICE_ATTR_RO(alarms); 235 static SENSOR_DEVICE_ATTR_RO(temp1_crit_alarm, alarm, 2); 236 static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, 0); 237 static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, 1); 238 239 /* 240 * Detection and registration 241 */ 242 243 static void lm92_init_client(struct i2c_client *client) 244 { 245 u8 config; 246 247 /* Start the conversions if needed */ 248 config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG); 249 if (config & 0x01) 250 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG, 251 config & 0xFE); 252 } 253 254 static struct attribute *lm92_attrs[] = { 255 &sensor_dev_attr_temp1_input.dev_attr.attr, 256 &sensor_dev_attr_temp1_crit.dev_attr.attr, 257 &sensor_dev_attr_temp1_crit_hyst.dev_attr.attr, 258 &sensor_dev_attr_temp1_min.dev_attr.attr, 259 &dev_attr_temp1_min_hyst.attr, 260 &sensor_dev_attr_temp1_max.dev_attr.attr, 261 &sensor_dev_attr_temp1_max_hyst.dev_attr.attr, 262 &dev_attr_alarms.attr, 263 &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr, 264 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr, 265 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr, 266 NULL 267 }; 268 ATTRIBUTE_GROUPS(lm92); 269 270 /* Return 0 if detection is successful, -ENODEV otherwise */ 271 static int lm92_detect(struct i2c_client *new_client, 272 struct i2c_board_info *info) 273 { 274 struct i2c_adapter *adapter = new_client->adapter; 275 u8 config_addr = LM92_REG_CONFIG; 276 u8 man_id_addr = LM92_REG_MAN_ID; 277 int i, regval; 278 279 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA 280 | I2C_FUNC_SMBUS_WORD_DATA)) 281 return -ENODEV; 282 283 /* 284 * Register values repeat with multiples of 8. 285 * Read twice to improve detection accuracy. 286 */ 287 for (i = 0; i < 2; i++) { 288 regval = i2c_smbus_read_word_data(new_client, man_id_addr); 289 if (regval != 0x0180) 290 return -ENODEV; 291 regval = i2c_smbus_read_byte_data(new_client, config_addr); 292 if (regval < 0 || (regval & 0xe0)) 293 return -ENODEV; 294 config_addr += 8; 295 man_id_addr += 8; 296 } 297 298 strscpy(info->type, "lm92", I2C_NAME_SIZE); 299 300 return 0; 301 } 302 303 static int lm92_probe(struct i2c_client *new_client) 304 { 305 struct device *hwmon_dev; 306 struct lm92_data *data; 307 308 data = devm_kzalloc(&new_client->dev, sizeof(struct lm92_data), 309 GFP_KERNEL); 310 if (!data) 311 return -ENOMEM; 312 313 data->client = new_client; 314 data->resolution = (unsigned long)i2c_get_match_data(new_client); 315 mutex_init(&data->update_lock); 316 317 /* Initialize the chipset */ 318 lm92_init_client(new_client); 319 320 hwmon_dev = devm_hwmon_device_register_with_groups(&new_client->dev, 321 new_client->name, 322 data, lm92_groups); 323 return PTR_ERR_OR_ZERO(hwmon_dev); 324 } 325 326 /* 327 * Module and driver stuff 328 */ 329 330 /* .driver_data is limit register resolution */ 331 static const struct i2c_device_id lm92_id[] = { 332 { "lm92", 13 }, 333 { "max6635", 9 }, 334 { } 335 }; 336 MODULE_DEVICE_TABLE(i2c, lm92_id); 337 338 static struct i2c_driver lm92_driver = { 339 .class = I2C_CLASS_HWMON, 340 .driver = { 341 .name = "lm92", 342 }, 343 .probe = lm92_probe, 344 .id_table = lm92_id, 345 .detect = lm92_detect, 346 .address_list = normal_i2c, 347 }; 348 349 module_i2c_driver(lm92_driver); 350 351 MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>"); 352 MODULE_DESCRIPTION("LM92/MAX6635 driver"); 353 MODULE_LICENSE("GPL"); 354