drivers/hwmon/max6620.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * Hardware monitoring driver for Maxim MAX6620
0004  *
0005  * Originally from L. Grunenberg.
0006  * (C) 2012 by L. Grunenberg <contact@lgrunenberg.de>
0007  *
0008  * Copyright (c) 2021 Dell Inc. or its subsidiaries. All Rights Reserved.
0009  *
0010  * based on code written by :
0011  * 2007 by Hans J. Koch <hjk@hansjkoch.de>
0012  * John Morris <john.morris@spirentcom.com>
0013  * Copyright (c) 2003 Spirent Communications
0014  * and Claus Gindhart <claus.gindhart@kontron.com>
0015  *
0016  * This module has only been tested with the MAX6620 chip.
0017  *
0018  * The datasheet was last seen at:
0019  *
0020  *        http://pdfserv.maxim-ic.com/en/ds/MAX6620.pdf
0021  *
0022  */
0023
0024 #include <linux/bits.h>
0025 #include <linux/err.h>
0026 #include <linux/hwmon.h>
0027 #include <linux/i2c.h>
0028 #include <linux/init.h>
0029 #include <linux/jiffies.h>
0030 #include <linux/module.h>
0031 #include <linux/slab.h>
0032
0033 /*
0034  * MAX 6620 registers
0035  */
0036
0037 #define MAX6620_REG_CONFIG  0x00
0038 #define MAX6620_REG_FAULT   0x01
0039 #define MAX6620_REG_CONF_FAN0   0x02
0040 #define MAX6620_REG_CONF_FAN1   0x03
0041 #define MAX6620_REG_CONF_FAN2   0x04
0042 #define MAX6620_REG_CONF_FAN3   0x05
0043 #define MAX6620_REG_DYN_FAN0    0x06
0044 #define MAX6620_REG_DYN_FAN1    0x07
0045 #define MAX6620_REG_DYN_FAN2    0x08
0046 #define MAX6620_REG_DYN_FAN3    0x09
0047 #define MAX6620_REG_TACH0   0x10
0048 #define MAX6620_REG_TACH1   0x12
0049 #define MAX6620_REG_TACH2   0x14
0050 #define MAX6620_REG_TACH3   0x16
0051 #define MAX6620_REG_VOLT0   0x18
0052 #define MAX6620_REG_VOLT1   0x1A
0053 #define MAX6620_REG_VOLT2   0x1C
0054 #define MAX6620_REG_VOLT3   0x1E
0055 #define MAX6620_REG_TAR0    0x20
0056 #define MAX6620_REG_TAR1    0x22
0057 #define MAX6620_REG_TAR2    0x24
0058 #define MAX6620_REG_TAR3    0x26
0059 #define MAX6620_REG_DAC0    0x28
0060 #define MAX6620_REG_DAC1    0x2A
0061 #define MAX6620_REG_DAC2    0x2C
0062 #define MAX6620_REG_DAC3    0x2E
0063
0064 /*
0065  * Config register bits
0066  */
0067
0068 #define MAX6620_CFG_RUN     BIT(7)
0069 #define MAX6620_CFG_POR     BIT(6)
0070 #define MAX6620_CFG_TIMEOUT BIT(5)
0071 #define MAX6620_CFG_FULLFAN BIT(4)
0072 #define MAX6620_CFG_OSC     BIT(3)
0073 #define MAX6620_CFG_WD_MASK (BIT(2) | BIT(1))
0074 #define MAX6620_CFG_WD_2    BIT(1)
0075 #define MAX6620_CFG_WD_6    BIT(2)
0076 #define MAX6620_CFG_WD10    (BIT(2) | BIT(1))
0077 #define MAX6620_CFG_WD      BIT(0)
0078
0079 /*
0080  * Failure status register bits
0081  */
0082
0083 #define MAX6620_FAIL_TACH0  BIT(4)
0084 #define MAX6620_FAIL_TACH1  BIT(5)
0085 #define MAX6620_FAIL_TACH2  BIT(6)
0086 #define MAX6620_FAIL_TACH3  BIT(7)
0087 #define MAX6620_FAIL_MASK0  BIT(0)
0088 #define MAX6620_FAIL_MASK1  BIT(1)
0089 #define MAX6620_FAIL_MASK2  BIT(2)
0090 #define MAX6620_FAIL_MASK3  BIT(3)
0091
0092 #define MAX6620_CLOCK_FREQ  8192 /* Clock frequency in Hz */
0093 #define MAX6620_PULSE_PER_REV   2 /* Tachometer pulses per revolution */
0094
0095 /* Minimum and maximum values of the FAN-RPM */
0096 #define FAN_RPM_MIN 240
0097 #define FAN_RPM_MAX 30000
0098
0099 static const u8 config_reg[] = {
0100     MAX6620_REG_CONF_FAN0,
0101     MAX6620_REG_CONF_FAN1,
0102     MAX6620_REG_CONF_FAN2,
0103     MAX6620_REG_CONF_FAN3,
0104 };
0105
0106 static const u8 dyn_reg[] = {
0107     MAX6620_REG_DYN_FAN0,
0108     MAX6620_REG_DYN_FAN1,
0109     MAX6620_REG_DYN_FAN2,
0110     MAX6620_REG_DYN_FAN3,
0111 };
0112
0113 static const u8 tach_reg[] = {
0114     MAX6620_REG_TACH0,
0115     MAX6620_REG_TACH1,
0116     MAX6620_REG_TACH2,
0117     MAX6620_REG_TACH3,
0118 };
0119
0120 static const u8 target_reg[] = {
0121     MAX6620_REG_TAR0,
0122     MAX6620_REG_TAR1,
0123     MAX6620_REG_TAR2,
0124     MAX6620_REG_TAR3,
0125 };
0126
0127 /*
0128  * Client data (each client gets its own)
0129  */
0130
0131 struct max6620_data {
0132     struct i2c_client *client;
0133     struct mutex update_lock;
0134     bool valid; /* false until following fields are valid */
0135     unsigned long last_updated; /* in jiffies */
0136
0137     /* register values */
0138     u8 fancfg[4];
0139     u8 fandyn[4];
0140     u8 fault;
0141     u16 tach[4];
0142     u16 target[4];
0143 };
0144
0145 static u8 max6620_fan_div_from_reg(u8 val)
0146 {
0147     return BIT((val & 0xE0) >> 5);
0148 }
0149
0150 static u16 max6620_fan_rpm_to_tach(u8 div, int rpm)
0151 {
0152     return (60 * div * MAX6620_CLOCK_FREQ) / (rpm * MAX6620_PULSE_PER_REV);
0153 }
0154
0155 static int max6620_fan_tach_to_rpm(u8 div, u16 tach)
0156 {
0157     return (60 * div * MAX6620_CLOCK_FREQ) / (tach * MAX6620_PULSE_PER_REV);
0158 }
0159
0160 static int max6620_update_device(struct device *dev)
0161 {
0162     struct max6620_data *data = dev_get_drvdata(dev);
0163     struct i2c_client *client = data->client;
0164     int i;
0165     int ret = 0;
0166
0167     mutex_lock(&data->update_lock);
0168
0169     if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
0170         for (i = 0; i < 4; i++) {
0171             ret = i2c_smbus_read_byte_data(client, config_reg[i]);
0172             if (ret < 0)
0173                 goto error;
0174             data->fancfg[i] = ret;
0175
0176             ret = i2c_smbus_read_byte_data(client, dyn_reg[i]);
0177             if (ret < 0)
0178                 goto error;
0179             data->fandyn[i] = ret;
0180
0181             ret = i2c_smbus_read_byte_data(client, tach_reg[i]);
0182             if (ret < 0)
0183                 goto error;
0184             data->tach[i] = (ret << 3) & 0x7f8;
0185             ret = i2c_smbus_read_byte_data(client, tach_reg[i] + 1);
0186             if (ret < 0)
0187                 goto error;
0188             data->tach[i] |= (ret >> 5) & 0x7;
0189
0190             ret = i2c_smbus_read_byte_data(client, target_reg[i]);
0191             if (ret < 0)
0192                 goto error;
0193             data->target[i] = (ret << 3) & 0x7f8;
0194             ret = i2c_smbus_read_byte_data(client, target_reg[i] + 1);
0195             if (ret < 0)
0196                 goto error;
0197             data->target[i] |= (ret >> 5) & 0x7;
0198         }
0199
0200         /*
0201          * Alarms are cleared on read in case the condition that
0202          * caused the alarm is removed. Keep the value latched here
0203          * for providing the register through different alarm files.
0204          */
0205         ret = i2c_smbus_read_byte_data(client, MAX6620_REG_FAULT);
0206         if (ret < 0)
0207             goto error;
0208         data->fault |= (ret >> 4) & (ret & 0x0F);
0209
0210         data->last_updated = jiffies;
0211         data->valid = true;
0212     }
0213
0214 error:
0215     mutex_unlock(&data->update_lock);
0216     return ret;
0217 }
0218
0219 static umode_t
0220 max6620_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr,
0221            int channel)
0222 {
0223     switch (type) {
0224     case hwmon_fan:
0225         switch (attr) {
0226         case hwmon_fan_alarm:
0227         case hwmon_fan_input:
0228             return 0444;
0229         case hwmon_fan_div:
0230         case hwmon_fan_target:
0231             return 0644;
0232         default:
0233             break;
0234         }
0235         break;
0236     default:
0237         break;
0238     }
0239
0240     return 0;
0241 }
0242
0243 static int
0244 max6620_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
0245          int channel, long *val)
0246 {
0247     struct max6620_data *data;
0248     struct i2c_client *client;
0249     int ret;
0250     u8 div;
0251     u8 val1;
0252     u8 val2;
0253
0254     ret = max6620_update_device(dev);
0255     if (ret < 0)
0256         return ret;
0257     data = dev_get_drvdata(dev);
0258     client = data->client;
0259
0260     switch (type) {
0261     case hwmon_fan:
0262         switch (attr) {
0263         case hwmon_fan_alarm:
0264             mutex_lock(&data->update_lock);
0265             *val = !!(data->fault & BIT(channel));
0266
0267             /* Setting TACH count to re-enable fan fault detection */
0268             if (*val == 1) {
0269                 val1 = (data->target[channel] >> 3) & 0xff;
0270                 val2 = (data->target[channel] << 5) & 0xe0;
0271                 ret = i2c_smbus_write_byte_data(client,
0272                                 target_reg[channel], val1);
0273                 if (ret < 0) {
0274                     mutex_unlock(&data->update_lock);
0275                     return ret;
0276                 }
0277                 ret = i2c_smbus_write_byte_data(client,
0278                                 target_reg[channel] + 1, val2);
0279                 if (ret < 0) {
0280                     mutex_unlock(&data->update_lock);
0281                     return ret;
0282                 }
0283
0284                 data->fault &= ~BIT(channel);
0285             }
0286             mutex_unlock(&data->update_lock);
0287
0288             break;
0289         case hwmon_fan_div:
0290             *val = max6620_fan_div_from_reg(data->fandyn[channel]);
0291             break;
0292         case hwmon_fan_input:
0293             if (data->tach[channel] == 0) {
0294                 *val = 0;
0295             } else {
0296                 div = max6620_fan_div_from_reg(data->fandyn[channel]);
0297                 *val = max6620_fan_tach_to_rpm(div, data->tach[channel]);
0298             }
0299             break;
0300         case hwmon_fan_target:
0301             if (data->target[channel] == 0) {
0302                 *val = 0;
0303             } else {
0304                 div = max6620_fan_div_from_reg(data->fandyn[channel]);
0305                 *val = max6620_fan_tach_to_rpm(div, data->target[channel]);
0306             }
0307             break;
0308         default:
0309             return -EOPNOTSUPP;
0310         }
0311         break;
0312
0313     default:
0314         return -EOPNOTSUPP;
0315     }
0316
0317     return 0;
0318 }
0319
0320 static int
0321 max6620_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
0322           int channel, long val)
0323 {
0324     struct max6620_data *data;
0325     struct i2c_client *client;
0326     int ret;
0327     u8 div;
0328     u16 tach;
0329     u8 val1;
0330     u8 val2;
0331
0332     ret = max6620_update_device(dev);
0333     if (ret < 0)
0334         return ret;
0335     data = dev_get_drvdata(dev);
0336     client = data->client;
0337     mutex_lock(&data->update_lock);
0338
0339     switch (type) {
0340     case hwmon_fan:
0341         switch (attr) {
0342         case hwmon_fan_div:
0343             switch (val) {
0344             case 1:
0345                 div = 0;
0346                 break;
0347             case 2:
0348                 div = 1;
0349                 break;
0350             case 4:
0351                 div = 2;
0352                 break;
0353             case 8:
0354                 div = 3;
0355                 break;
0356             case 16:
0357                 div = 4;
0358                 break;
0359             case 32:
0360                 div = 5;
0361                 break;
0362             default:
0363                 ret = -EINVAL;
0364                 goto error;
0365             }
0366             data->fandyn[channel] &= 0x1F;
0367             data->fandyn[channel] |= div << 5;
0368             ret = i2c_smbus_write_byte_data(client, dyn_reg[channel],
0369                             data->fandyn[channel]);
0370             break;
0371         case hwmon_fan_target:
0372             val = clamp_val(val, FAN_RPM_MIN, FAN_RPM_MAX);
0373             div = max6620_fan_div_from_reg(data->fandyn[channel]);
0374             tach = max6620_fan_rpm_to_tach(div, val);
0375             val1 = (tach >> 3) & 0xff;
0376             val2 = (tach << 5) & 0xe0;
0377             ret = i2c_smbus_write_byte_data(client, target_reg[channel], val1);
0378             if (ret < 0)
0379                 break;
0380             ret = i2c_smbus_write_byte_data(client, target_reg[channel] + 1, val2);
0381             if (ret < 0)
0382                 break;
0383
0384             /* Setting TACH count re-enables fan fault detection */
0385             data->fault &= ~BIT(channel);
0386
0387             break;
0388         default:
0389             ret = -EOPNOTSUPP;
0390             break;
0391         }
0392         break;
0393
0394     default:
0395         ret = -EOPNOTSUPP;
0396         break;
0397     }
0398
0399 error:
0400     mutex_unlock(&data->update_lock);
0401     return ret;
0402 }
0403
0404 static const struct hwmon_channel_info *max6620_info[] = {
0405     HWMON_CHANNEL_INFO(fan,
0406                HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM,
0407                HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM,
0408                HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM,
0409                HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM),
0410     NULL
0411 };
0412
0413 static const struct hwmon_ops max6620_hwmon_ops = {
0414     .read = max6620_read,
0415     .write = max6620_write,
0416     .is_visible = max6620_is_visible,
0417 };
0418
0419 static const struct hwmon_chip_info max6620_chip_info = {
0420     .ops = &max6620_hwmon_ops,
0421     .info = max6620_info,
0422 };
0423
0424 static int max6620_init_client(struct max6620_data *data)
0425 {
0426     struct i2c_client *client = data->client;
0427     int config;
0428     int err;
0429     int i;
0430     int reg;
0431
0432     config = i2c_smbus_read_byte_data(client, MAX6620_REG_CONFIG);
0433     if (config < 0) {
0434         dev_err(&client->dev, "Error reading config, aborting.\n");
0435         return config;
0436     }
0437
0438     /*
0439      * Set bit 4, disable other fans from going full speed on a fail
0440      * failure.
0441      */
0442     err = i2c_smbus_write_byte_data(client, MAX6620_REG_CONFIG, config | 0x10);
0443     if (err < 0) {
0444         dev_err(&client->dev, "Config write error, aborting.\n");
0445         return err;
0446     }
0447
0448     for (i = 0; i < 4; i++) {
0449         reg = i2c_smbus_read_byte_data(client, config_reg[i]);
0450         if (reg < 0)
0451             return reg;
0452         data->fancfg[i] = reg;
0453
0454         /* Enable RPM mode */
0455         data->fancfg[i] |= 0xa8;
0456         err = i2c_smbus_write_byte_data(client, config_reg[i], data->fancfg[i]);
0457         if (err < 0)
0458             return err;
0459
0460         /* 2 counts (001) and Rate change 100 (0.125 secs) */
0461         data->fandyn[i] = 0x30;
0462         err = i2c_smbus_write_byte_data(client, dyn_reg[i], data->fandyn[i]);
0463         if (err < 0)
0464             return err;
0465     }
0466     return 0;
0467 }
0468
0469 static int max6620_probe(struct i2c_client *client)
0470 {
0471     struct device *dev = &client->dev;
0472     struct max6620_data *data;
0473     struct device *hwmon_dev;
0474     int err;
0475
0476     data = devm_kzalloc(dev, sizeof(struct max6620_data), GFP_KERNEL);
0477     if (!data)
0478         return -ENOMEM;
0479
0480     data->client = client;
0481     mutex_init(&data->update_lock);
0482
0483     err = max6620_init_client(data);
0484     if (err)
0485         return err;
0486
0487     hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
0488                              data,
0489                              &max6620_chip_info,
0490                              NULL);
0491
0492     return PTR_ERR_OR_ZERO(hwmon_dev);
0493 }
0494
0495 static const struct i2c_device_id max6620_id[] = {
0496     { "max6620", 0 },
0497     { }
0498 };
0499 MODULE_DEVICE_TABLE(i2c, max6620_id);
0500
0501 static struct i2c_driver max6620_driver = {
0502     .class      = I2C_CLASS_HWMON,
0503     .driver = {
0504         .name   = "max6620",
0505     },
0506     .probe_new  = max6620_probe,
0507     .id_table   = max6620_id,
0508 };
0509
0510 module_i2c_driver(max6620_driver);
0511
0512 MODULE_AUTHOR("Lucas Grunenberg");
0513 MODULE_DESCRIPTION("MAX6620 sensor driver");
0514 MODULE_LICENSE("GPL");