1 /* 2 * Driver for +/-1 degree C, SMBus-Compatible Remote/Local Temperature Sensor 3 * with Overtemperature Alarm 4 * 5 * Copyright (C) 2011 AppearTV AS 6 * 7 * Derived from: 8 * 9 * Based on the max1619 driver. 10 * Copyright (C) 2003-2004 Oleksij Rempel <bug-track@fisher-privat.net> 11 * Jean Delvare <jdelvare@suse.de> 12 * 13 * The MAX6642 is a sensor chip made by Maxim. 14 * It reports up to two temperatures (its own plus up to 15 * one external one). Complete datasheet can be 16 * obtained from Maxim's website at: 17 * http://datasheets.maxim-ic.com/en/ds/MAX6642.pdf 18 * 19 * This program is free software; you can redistribute it and/or modify 20 * it under the terms of the GNU General Public License as published by 21 * the Free Software Foundation; either version 2 of the License, or 22 * (at your option) any later version. 23 * 24 * This program is distributed in the hope that it will be useful, 25 * but WITHOUT ANY WARRANTY; without even the implied warranty of 26 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 27 * GNU General Public License for more details. 28 * 29 * You should have received a copy of the GNU General Public License 30 * along with this program; if not, write to the Free Software 31 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 32 */ 33 34 35 #include <linux/module.h> 36 #include <linux/init.h> 37 #include <linux/slab.h> 38 #include <linux/jiffies.h> 39 #include <linux/i2c.h> 40 #include <linux/hwmon.h> 41 #include <linux/hwmon-sysfs.h> 42 #include <linux/err.h> 43 #include <linux/mutex.h> 44 #include <linux/sysfs.h> 45 46 static const unsigned short normal_i2c[] = { 47 0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, I2C_CLIENT_END }; 48 49 /* 50 * The MAX6642 registers 51 */ 52 53 #define MAX6642_REG_R_MAN_ID 0xFE 54 #define MAX6642_REG_R_CONFIG 0x03 55 #define MAX6642_REG_W_CONFIG 0x09 56 #define MAX6642_REG_R_STATUS 0x02 57 #define MAX6642_REG_R_LOCAL_TEMP 0x00 58 #define MAX6642_REG_R_LOCAL_TEMPL 0x11 59 #define MAX6642_REG_R_LOCAL_HIGH 0x05 60 #define MAX6642_REG_W_LOCAL_HIGH 0x0B 61 #define MAX6642_REG_R_REMOTE_TEMP 0x01 62 #define MAX6642_REG_R_REMOTE_TEMPL 0x10 63 #define MAX6642_REG_R_REMOTE_HIGH 0x07 64 #define MAX6642_REG_W_REMOTE_HIGH 0x0D 65 66 /* 67 * Conversions 68 */ 69 70 static int temp_from_reg10(int val) 71 { 72 return val * 250; 73 } 74 75 static int temp_from_reg(int val) 76 { 77 return val * 1000; 78 } 79 80 static int temp_to_reg(int val) 81 { 82 return val / 1000; 83 } 84 85 /* 86 * Client data (each client gets its own) 87 */ 88 89 struct max6642_data { 90 struct i2c_client *client; 91 struct mutex update_lock; 92 bool valid; /* zero until following fields are valid */ 93 unsigned long last_updated; /* in jiffies */ 94 95 /* registers values */ 96 u16 temp_input[2]; /* local/remote */ 97 u16 temp_high[2]; /* local/remote */ 98 u8 alarms; 99 }; 100 101 /* 102 * Real code 103 */ 104 105 static void max6642_init_client(struct max6642_data *data, 106 struct i2c_client *client) 107 { 108 u8 config; 109 110 /* 111 * Start the conversions. 112 */ 113 config = i2c_smbus_read_byte_data(client, MAX6642_REG_R_CONFIG); 114 if (config & 0x40) 115 i2c_smbus_write_byte_data(client, MAX6642_REG_W_CONFIG, 116 config & 0xBF); /* run */ 117 118 data->temp_high[0] = i2c_smbus_read_byte_data(client, 119 MAX6642_REG_R_LOCAL_HIGH); 120 data->temp_high[1] = i2c_smbus_read_byte_data(client, 121 MAX6642_REG_R_REMOTE_HIGH); 122 } 123 124 /* Return 0 if detection is successful, -ENODEV otherwise */ 125 static int max6642_detect(struct i2c_client *client, 126 struct i2c_board_info *info) 127 { 128 struct i2c_adapter *adapter = client->adapter; 129 u8 reg_config, reg_status, man_id; 130 131 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) 132 return -ENODEV; 133 134 /* identification */ 135 man_id = i2c_smbus_read_byte_data(client, MAX6642_REG_R_MAN_ID); 136 if (man_id != 0x4D) 137 return -ENODEV; 138 139 /* sanity check */ 140 if (i2c_smbus_read_byte_data(client, 0x04) != 0x4D 141 || i2c_smbus_read_byte_data(client, 0x06) != 0x4D 142 || i2c_smbus_read_byte_data(client, 0xff) != 0x4D) 143 return -ENODEV; 144 145 /* 146 * We read the config and status register, the 4 lower bits in the 147 * config register should be zero and bit 5, 3, 1 and 0 should be 148 * zero in the status register. 149 */ 150 reg_config = i2c_smbus_read_byte_data(client, MAX6642_REG_R_CONFIG); 151 if ((reg_config & 0x0f) != 0x00) 152 return -ENODEV; 153 154 /* in between, another round of sanity checks */ 155 if (i2c_smbus_read_byte_data(client, 0x04) != reg_config 156 || i2c_smbus_read_byte_data(client, 0x06) != reg_config 157 || i2c_smbus_read_byte_data(client, 0xff) != reg_config) 158 return -ENODEV; 159 160 reg_status = i2c_smbus_read_byte_data(client, MAX6642_REG_R_STATUS); 161 if ((reg_status & 0x2b) != 0x00) 162 return -ENODEV; 163 164 strlcpy(info->type, "max6642", I2C_NAME_SIZE); 165 166 return 0; 167 } 168 169 static struct max6642_data *max6642_update_device(struct device *dev) 170 { 171 struct max6642_data *data = dev_get_drvdata(dev); 172 struct i2c_client *client = data->client; 173 u16 val, tmp; 174 175 mutex_lock(&data->update_lock); 176 177 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) { 178 dev_dbg(dev, "Updating max6642 data.\n"); 179 val = i2c_smbus_read_byte_data(client, 180 MAX6642_REG_R_LOCAL_TEMPL); 181 tmp = (val >> 6) & 3; 182 val = i2c_smbus_read_byte_data(client, 183 MAX6642_REG_R_LOCAL_TEMP); 184 val = (val << 2) | tmp; 185 data->temp_input[0] = val; 186 val = i2c_smbus_read_byte_data(client, 187 MAX6642_REG_R_REMOTE_TEMPL); 188 tmp = (val >> 6) & 3; 189 val = i2c_smbus_read_byte_data(client, 190 MAX6642_REG_R_REMOTE_TEMP); 191 val = (val << 2) | tmp; 192 data->temp_input[1] = val; 193 data->alarms = i2c_smbus_read_byte_data(client, 194 MAX6642_REG_R_STATUS); 195 196 data->last_updated = jiffies; 197 data->valid = 1; 198 } 199 200 mutex_unlock(&data->update_lock); 201 202 return data; 203 } 204 205 /* 206 * Sysfs stuff 207 */ 208 209 static ssize_t temp_max10_show(struct device *dev, 210 struct device_attribute *dev_attr, char *buf) 211 { 212 struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr); 213 struct max6642_data *data = max6642_update_device(dev); 214 215 return sprintf(buf, "%d\n", 216 temp_from_reg10(data->temp_input[attr->index])); 217 } 218 219 static ssize_t temp_max_show(struct device *dev, 220 struct device_attribute *attr, char *buf) 221 { 222 struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr); 223 struct max6642_data *data = max6642_update_device(dev); 224 225 return sprintf(buf, "%d\n", temp_from_reg(data->temp_high[attr2->nr])); 226 } 227 228 static ssize_t temp_max_store(struct device *dev, 229 struct device_attribute *attr, const char *buf, 230 size_t count) 231 { 232 struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr); 233 struct max6642_data *data = dev_get_drvdata(dev); 234 unsigned long val; 235 int err; 236 237 err = kstrtoul(buf, 10, &val); 238 if (err < 0) 239 return err; 240 241 mutex_lock(&data->update_lock); 242 data->temp_high[attr2->nr] = clamp_val(temp_to_reg(val), 0, 255); 243 i2c_smbus_write_byte_data(data->client, attr2->index, 244 data->temp_high[attr2->nr]); 245 mutex_unlock(&data->update_lock); 246 return count; 247 } 248 249 static ssize_t alarm_show(struct device *dev, struct device_attribute *attr, 250 char *buf) 251 { 252 int bitnr = to_sensor_dev_attr(attr)->index; 253 struct max6642_data *data = max6642_update_device(dev); 254 return sprintf(buf, "%d\n", (data->alarms >> bitnr) & 1); 255 } 256 257 static SENSOR_DEVICE_ATTR_RO(temp1_input, temp_max10, 0); 258 static SENSOR_DEVICE_ATTR_RO(temp2_input, temp_max10, 1); 259 static SENSOR_DEVICE_ATTR_2_RW(temp1_max, temp_max, 0, 260 MAX6642_REG_W_LOCAL_HIGH); 261 static SENSOR_DEVICE_ATTR_2_RW(temp2_max, temp_max, 1, 262 MAX6642_REG_W_REMOTE_HIGH); 263 static SENSOR_DEVICE_ATTR_RO(temp2_fault, alarm, 2); 264 static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, 6); 265 static SENSOR_DEVICE_ATTR_RO(temp2_max_alarm, alarm, 4); 266 267 static struct attribute *max6642_attrs[] = { 268 &sensor_dev_attr_temp1_input.dev_attr.attr, 269 &sensor_dev_attr_temp2_input.dev_attr.attr, 270 &sensor_dev_attr_temp1_max.dev_attr.attr, 271 &sensor_dev_attr_temp2_max.dev_attr.attr, 272 273 &sensor_dev_attr_temp2_fault.dev_attr.attr, 274 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr, 275 &sensor_dev_attr_temp2_max_alarm.dev_attr.attr, 276 NULL 277 }; 278 ATTRIBUTE_GROUPS(max6642); 279 280 static int max6642_probe(struct i2c_client *client, 281 const struct i2c_device_id *id) 282 { 283 struct device *dev = &client->dev; 284 struct max6642_data *data; 285 struct device *hwmon_dev; 286 287 data = devm_kzalloc(dev, sizeof(struct max6642_data), GFP_KERNEL); 288 if (!data) 289 return -ENOMEM; 290 291 data->client = client; 292 mutex_init(&data->update_lock); 293 294 /* Initialize the MAX6642 chip */ 295 max6642_init_client(data, client); 296 297 hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev, 298 client->name, data, 299 max6642_groups); 300 return PTR_ERR_OR_ZERO(hwmon_dev); 301 } 302 303 /* 304 * Driver data (common to all clients) 305 */ 306 307 static const struct i2c_device_id max6642_id[] = { 308 { "max6642", 0 }, 309 { } 310 }; 311 MODULE_DEVICE_TABLE(i2c, max6642_id); 312 313 static struct i2c_driver max6642_driver = { 314 .class = I2C_CLASS_HWMON, 315 .driver = { 316 .name = "max6642", 317 }, 318 .probe = max6642_probe, 319 .id_table = max6642_id, 320 .detect = max6642_detect, 321 .address_list = normal_i2c, 322 }; 323 324 module_i2c_driver(max6642_driver); 325 326 MODULE_AUTHOR("Per Dalen <per.dalen@appeartv.com>"); 327 MODULE_DESCRIPTION("MAX6642 sensor driver"); 328 MODULE_LICENSE("GPL"); 329