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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * lm77.c - Part of lm_sensors, Linux kernel modules for hardware4 * monitoring5 *6 * Copyright (c) 2004 Andras BALI <drewie@freemail.hu>7 *8 * Heavily based on lm75.c by Frodo Looijaard <frodol@dds.nl>. The LM779 * is a temperature sensor and thermal window comparator with 0.5 deg10 * resolution made by National Semiconductor. Complete datasheet can be11 * obtained at their site:12 * http://www.national.com/pf/LM/LM77.html13 */14 15#include <linux/module.h>16#include <linux/init.h>17#include <linux/slab.h>18#include <linux/jiffies.h>19#include <linux/i2c.h>20#include <linux/hwmon.h>21#include <linux/hwmon-sysfs.h>22#include <linux/err.h>23#include <linux/mutex.h>24 25/* Addresses to scan */26static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,27 I2C_CLIENT_END };28 29/* The LM77 registers */30#define LM77_REG_TEMP 0x0031#define LM77_REG_CONF 0x0132#define LM77_REG_TEMP_HYST 0x0233#define LM77_REG_TEMP_CRIT 0x0334#define LM77_REG_TEMP_MIN 0x0435#define LM77_REG_TEMP_MAX 0x0536 37enum temp_index {38 t_input = 0,39 t_crit,40 t_min,41 t_max,42 t_hyst,43 t_num_temp44};45 46static const u8 temp_regs[t_num_temp] = {47 [t_input] = LM77_REG_TEMP,48 [t_min] = LM77_REG_TEMP_MIN,49 [t_max] = LM77_REG_TEMP_MAX,50 [t_crit] = LM77_REG_TEMP_CRIT,51 [t_hyst] = LM77_REG_TEMP_HYST,52};53 54/* Each client has this additional data */55struct lm77_data {56 struct i2c_client *client;57 struct mutex update_lock;58 bool valid;59 unsigned long last_updated; /* In jiffies */60 int temp[t_num_temp]; /* index using temp_index */61 u8 alarms;62};63 64/* straight from the datasheet */65#define LM77_TEMP_MIN (-55000)66#define LM77_TEMP_MAX 12500067 68/*69 * In the temperature registers, the low 3 bits are not part of the70 * temperature values; they are the status bits.71 */72static inline s16 LM77_TEMP_TO_REG(int temp)73{74 return (temp / 500) * 8;75}76 77static inline int LM77_TEMP_FROM_REG(s16 reg)78{79 return (reg / 8) * 500;80}81 82/*83 * All registers are word-sized, except for the configuration register.84 * The LM77 uses the high-byte first convention.85 */86static u16 lm77_read_value(struct i2c_client *client, u8 reg)87{88 if (reg == LM77_REG_CONF)89 return i2c_smbus_read_byte_data(client, reg);90 else91 return i2c_smbus_read_word_swapped(client, reg);92}93 94static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value)95{96 if (reg == LM77_REG_CONF)97 return i2c_smbus_write_byte_data(client, reg, value);98 else99 return i2c_smbus_write_word_swapped(client, reg, value);100}101 102static struct lm77_data *lm77_update_device(struct device *dev)103{104 struct lm77_data *data = dev_get_drvdata(dev);105 struct i2c_client *client = data->client;106 int i;107 108 mutex_lock(&data->update_lock);109 110 if (time_after(jiffies, data->last_updated + HZ + HZ / 2)111 || !data->valid) {112 dev_dbg(&client->dev, "Starting lm77 update\n");113 for (i = 0; i < t_num_temp; i++) {114 data->temp[i] =115 LM77_TEMP_FROM_REG(lm77_read_value(client,116 temp_regs[i]));117 }118 data->alarms =119 lm77_read_value(client, LM77_REG_TEMP) & 0x0007;120 data->last_updated = jiffies;121 data->valid = true;122 }123 124 mutex_unlock(&data->update_lock);125 126 return data;127}128 129/* sysfs stuff */130 131static ssize_t temp_show(struct device *dev, struct device_attribute *devattr,132 char *buf)133{134 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);135 struct lm77_data *data = lm77_update_device(dev);136 137 return sprintf(buf, "%d\n", data->temp[attr->index]);138}139 140static ssize_t temp_hyst_show(struct device *dev,141 struct device_attribute *devattr, char *buf)142{143 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);144 struct lm77_data *data = lm77_update_device(dev);145 int nr = attr->index;146 int temp;147 148 temp = nr == t_min ? data->temp[nr] + data->temp[t_hyst] :149 data->temp[nr] - data->temp[t_hyst];150 151 return sprintf(buf, "%d\n", temp);152}153 154static ssize_t temp_store(struct device *dev,155 struct device_attribute *devattr, const char *buf,156 size_t count)157{158 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);159 struct lm77_data *data = dev_get_drvdata(dev);160 struct i2c_client *client = data->client;161 int nr = attr->index;162 long val;163 int err;164 165 err = kstrtol(buf, 10, &val);166 if (err)167 return err;168 169 val = clamp_val(val, LM77_TEMP_MIN, LM77_TEMP_MAX);170 mutex_lock(&data->update_lock);171 data->temp[nr] = val;172 lm77_write_value(client, temp_regs[nr], LM77_TEMP_TO_REG(val));173 mutex_unlock(&data->update_lock);174 return count;175}176 177/*178 * hysteresis is stored as a relative value on the chip, so it has to be179 * converted first.180 */181static ssize_t temp_hyst_store(struct device *dev,182 struct device_attribute *devattr,183 const char *buf, size_t count)184{185 struct lm77_data *data = dev_get_drvdata(dev);186 struct i2c_client *client = data->client;187 long val;188 int err;189 190 err = kstrtol(buf, 10, &val);191 if (err)192 return err;193 194 mutex_lock(&data->update_lock);195 val = clamp_val(data->temp[t_crit] - val, LM77_TEMP_MIN, LM77_TEMP_MAX);196 data->temp[t_hyst] = val;197 lm77_write_value(client, LM77_REG_TEMP_HYST,198 LM77_TEMP_TO_REG(data->temp[t_hyst]));199 mutex_unlock(&data->update_lock);200 return count;201}202 203static ssize_t alarm_show(struct device *dev, struct device_attribute *attr,204 char *buf)205{206 int bitnr = to_sensor_dev_attr(attr)->index;207 struct lm77_data *data = lm77_update_device(dev);208 return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1);209}210 211static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, t_input);212static SENSOR_DEVICE_ATTR_RW(temp1_crit, temp, t_crit);213static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, t_min);214static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, t_max);215 216static SENSOR_DEVICE_ATTR_RW(temp1_crit_hyst, temp_hyst, t_crit);217static SENSOR_DEVICE_ATTR_RO(temp1_min_hyst, temp_hyst, t_min);218static SENSOR_DEVICE_ATTR_RO(temp1_max_hyst, temp_hyst, t_max);219 220static SENSOR_DEVICE_ATTR_RO(temp1_crit_alarm, alarm, 2);221static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, 0);222static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, 1);223 224static struct attribute *lm77_attrs[] = {225 &sensor_dev_attr_temp1_input.dev_attr.attr,226 &sensor_dev_attr_temp1_crit.dev_attr.attr,227 &sensor_dev_attr_temp1_min.dev_attr.attr,228 &sensor_dev_attr_temp1_max.dev_attr.attr,229 &sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,230 &sensor_dev_attr_temp1_min_hyst.dev_attr.attr,231 &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,232 &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,233 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,234 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,235 NULL236};237ATTRIBUTE_GROUPS(lm77);238 239/* Return 0 if detection is successful, -ENODEV otherwise */240static int lm77_detect(struct i2c_client *client, struct i2c_board_info *info)241{242 struct i2c_adapter *adapter = client->adapter;243 int i, cur, conf, hyst, crit, min, max;244 245 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |246 I2C_FUNC_SMBUS_WORD_DATA))247 return -ENODEV;248 249 /*250 * Here comes the remaining detection. Since the LM77 has no251 * register dedicated to identification, we have to rely on the252 * following tricks:253 *254 * 1. the high 4 bits represent the sign and thus they should255 * always be the same256 * 2. the high 3 bits are unused in the configuration register257 * 3. addresses 0x06 and 0x07 return the last read value258 * 4. registers cycling over 8-address boundaries259 *260 * Word-sized registers are high-byte first.261 */262 263 /* addresses cycling */264 cur = i2c_smbus_read_word_data(client, 0);265 conf = i2c_smbus_read_byte_data(client, 1);266 hyst = i2c_smbus_read_word_data(client, 2);267 crit = i2c_smbus_read_word_data(client, 3);268 min = i2c_smbus_read_word_data(client, 4);269 max = i2c_smbus_read_word_data(client, 5);270 for (i = 8; i <= 0xff; i += 8) {271 if (i2c_smbus_read_byte_data(client, i + 1) != conf272 || i2c_smbus_read_word_data(client, i + 2) != hyst273 || i2c_smbus_read_word_data(client, i + 3) != crit274 || i2c_smbus_read_word_data(client, i + 4) != min275 || i2c_smbus_read_word_data(client, i + 5) != max)276 return -ENODEV;277 }278 279 /* sign bits */280 if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0)281 || ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0)282 || ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0)283 || ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0)284 || ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0))285 return -ENODEV;286 287 /* unused bits */288 if (conf & 0xe0)289 return -ENODEV;290 291 /* 0x06 and 0x07 return the last read value */292 cur = i2c_smbus_read_word_data(client, 0);293 if (i2c_smbus_read_word_data(client, 6) != cur294 || i2c_smbus_read_word_data(client, 7) != cur)295 return -ENODEV;296 hyst = i2c_smbus_read_word_data(client, 2);297 if (i2c_smbus_read_word_data(client, 6) != hyst298 || i2c_smbus_read_word_data(client, 7) != hyst)299 return -ENODEV;300 min = i2c_smbus_read_word_data(client, 4);301 if (i2c_smbus_read_word_data(client, 6) != min302 || i2c_smbus_read_word_data(client, 7) != min)303 return -ENODEV;304 305 strscpy(info->type, "lm77", I2C_NAME_SIZE);306 307 return 0;308}309 310static void lm77_init_client(struct i2c_client *client)311{312 /* Initialize the LM77 chip - turn off shutdown mode */313 int conf = lm77_read_value(client, LM77_REG_CONF);314 if (conf & 1)315 lm77_write_value(client, LM77_REG_CONF, conf & 0xfe);316}317 318static int lm77_probe(struct i2c_client *client)319{320 struct device *dev = &client->dev;321 struct device *hwmon_dev;322 struct lm77_data *data;323 324 data = devm_kzalloc(dev, sizeof(struct lm77_data), GFP_KERNEL);325 if (!data)326 return -ENOMEM;327 328 data->client = client;329 mutex_init(&data->update_lock);330 331 /* Initialize the LM77 chip */332 lm77_init_client(client);333 334 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,335 data, lm77_groups);336 return PTR_ERR_OR_ZERO(hwmon_dev);337}338 339static const struct i2c_device_id lm77_id[] = {340 { "lm77" },341 { }342};343MODULE_DEVICE_TABLE(i2c, lm77_id);344 345/* This is the driver that will be inserted */346static struct i2c_driver lm77_driver = {347 .class = I2C_CLASS_HWMON,348 .driver = {349 .name = "lm77",350 },351 .probe = lm77_probe,352 .id_table = lm77_id,353 .detect = lm77_detect,354 .address_list = normal_i2c,355};356 357module_i2c_driver(lm77_driver);358 359MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>");360MODULE_DESCRIPTION("LM77 driver");361MODULE_LICENSE("GPL");362