drivers/hwmon/max1668.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (c) 2011 David George <david.george@ska.ac.za>
   4  *
   5  * based on adm1021.c
   6  * some credit to Christoph Scheurer, but largely a rewrite
   7  */
   8
   9 #include <linux/bitops.h>
  10 #include <linux/bits.h>
  11 #include <linux/err.h>
  12 #include <linux/hwmon.h>
  13 #include <linux/i2c.h>
  14 #include <linux/init.h>
  15 #include <linux/module.h>
  16 #include <linux/regmap.h>
  17 #include <linux/slab.h>
  18
  19 /* Addresses to scan */
  20 static const unsigned short max1668_addr_list[] = {
  21         0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, 0x4c, 0x4d, 0x4e, I2C_CLIENT_END };
  22
  23 /* max1668 registers */
  24
  25 #define MAX1668_REG_TEMP(nr)    (nr)
  26 #define MAX1668_REG_STAT1       0x05
  27 #define MAX1668_REG_STAT2       0x06
  28 #define MAX1668_REG_MAN_ID      0xfe
  29 #define MAX1668_REG_DEV_ID      0xff
  30
  31 /* limits */
  32
  33 /* high limits */
  34 #define MAX1668_REG_LIMH(nr)    (0x08 + 2 * (nr))
  35 /* read low limits */
  36 #define MAX1668_REG_LIML(nr)    (0x09 + 2 * (nr))
  37
  38 /* manufacturer and device ID Constants */
  39 #define MAN_ID_MAXIM            0x4d
  40 #define DEV_ID_MAX1668          0x3
  41 #define DEV_ID_MAX1805          0x5
  42 #define DEV_ID_MAX1989          0xb
  43
  44 /* read only mode module parameter */
  45 static bool read_only;
  46 module_param(read_only, bool, 0);
  47 MODULE_PARM_DESC(read_only, "Don't set any values, read only mode");
  48
  49 struct max1668_data {
  50         struct regmap *regmap;
  51         int channels;
  52 };
  53
  54 static int max1668_read(struct device *dev, enum hwmon_sensor_types type,
  55                         u32 attr, int channel, long *val)
  56 {
  57         struct max1668_data *data = dev_get_drvdata(dev);
  58         struct regmap *regmap = data->regmap;
  59         u32 regs[2] = { MAX1668_REG_STAT1, MAX1668_REG_TEMP(channel) };
  60         u8 regvals[2];
  61         u32 regval;
  62         int ret;
  63
  64         switch (attr) {
  65         case hwmon_temp_input:
  66                 ret = regmap_read(regmap, MAX1668_REG_TEMP(channel), &regval);
  67                 if (ret)
  68                         return ret;
  69                 *val = sign_extend32(regval, 7) * 1000;
  70                 break;
  71         case hwmon_temp_min:
  72                 ret = regmap_read(regmap, MAX1668_REG_LIML(channel), &regval);
  73                 if (ret)
  74                         return ret;
  75                 *val = sign_extend32(regval, 7) * 1000;
  76                 break;
  77         case hwmon_temp_max:
  78                 ret = regmap_read(regmap, MAX1668_REG_LIMH(channel), &regval);
  79                 if (ret)
  80                         return ret;
  81                 *val = sign_extend32(regval, 7) * 1000;
  82                 break;
  83         case hwmon_temp_min_alarm:
  84                 ret = regmap_read(regmap,
  85                                   channel ? MAX1668_REG_STAT2 : MAX1668_REG_STAT1,
  86                                   &regval);
  87                 if (ret)
  88                         return ret;
  89                 if (channel)
  90                         *val = !!(regval & BIT(9 - channel * 2));
  91                 else
  92                         *val = !!(regval & BIT(5));
  93                 break;
  94         case hwmon_temp_max_alarm:
  95                 ret = regmap_read(regmap,
  96                                   channel ? MAX1668_REG_STAT2 : MAX1668_REG_STAT1,
  97                                   &regval);
  98                 if (ret)
  99                         return ret;
 100                 if (channel)
 101                         *val = !!(regval & BIT(8 - channel * 2));
 102                 else
 103                         *val = !!(regval & BIT(6));
 104                 break;
 105         case hwmon_temp_fault:
 106                 ret = regmap_multi_reg_read(regmap, regs, regvals, 2);
 107                 if (ret)
 108                         return ret;
 109                 *val = !!((regvals[0] & BIT(4)) && regvals[1] == 127);
 110                 break;
 111         default:
 112                 return -EOPNOTSUPP;
 113         }
 114         return 0;
 115 }
 116
 117 static int max1668_write(struct device *dev, enum hwmon_sensor_types type,
 118                          u32 attr, int channel, long val)
 119 {
 120         struct max1668_data *data = dev_get_drvdata(dev);
 121         struct regmap *regmap = data->regmap;
 122
 123         val = clamp_val(val / 1000, -128, 127);
 124
 125         switch (attr) {
 126         case hwmon_temp_min:
 127                 return regmap_write(regmap, MAX1668_REG_LIML(channel), val);
 128         case hwmon_temp_max:
 129                 return regmap_write(regmap, MAX1668_REG_LIMH(channel), val);
 130         default:
 131                 return -EOPNOTSUPP;
 132         }
 133 }
 134
 135 static umode_t max1668_is_visible(const void *_data, enum hwmon_sensor_types type,
 136                                   u32 attr, int channel)
 137 {
 138         const struct max1668_data *data = _data;
 139
 140         if (channel >= data->channels)
 141                 return 0;
 142
 143         switch (attr) {
 144         case hwmon_temp_min:
 145         case hwmon_temp_max:
 146                 return read_only ? 0444 : 0644;
 147         case hwmon_temp_input:
 148         case hwmon_temp_min_alarm:
 149         case hwmon_temp_max_alarm:
 150                 return 0444;
 151         case hwmon_temp_fault:
 152                 if (channel)
 153                         return 0444;
 154                 break;
 155         default:
 156                 break;
 157         }
 158         return 0;
 159 }
 160
 161 static const struct hwmon_channel_info * const max1668_info[] = {
 162         HWMON_CHANNEL_INFO(temp,
 163                            HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
 164                            HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM,
 165                            HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
 166                            HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
 167                            HWMON_T_FAULT,
 168                            HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
 169                            HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
 170                            HWMON_T_FAULT,
 171                            HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
 172                            HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
 173                            HWMON_T_FAULT,
 174                            HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
 175                            HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
 176                            HWMON_T_FAULT),
 177         NULL
 178 };
 179
 180 static const struct hwmon_ops max1668_hwmon_ops = {
 181         .is_visible = max1668_is_visible,
 182         .read = max1668_read,
 183         .write = max1668_write,
 184 };
 185
 186 static const struct hwmon_chip_info max1668_chip_info = {
 187         .ops = &max1668_hwmon_ops,
 188         .info = max1668_info,
 189 };
 190
 191 /* Return 0 if detection is successful, -ENODEV otherwise */
 192 static int max1668_detect(struct i2c_client *client,
 193                           struct i2c_board_info *info)
 194 {
 195         struct i2c_adapter *adapter = client->adapter;
 196         const char *type_name;
 197         int man_id, dev_id;
 198
 199         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 200                 return -ENODEV;
 201
 202         /* Check for unsupported part */
 203         man_id = i2c_smbus_read_byte_data(client, MAX1668_REG_MAN_ID);
 204         if (man_id != MAN_ID_MAXIM)
 205                 return -ENODEV;
 206
 207         dev_id = i2c_smbus_read_byte_data(client, MAX1668_REG_DEV_ID);
 208         if (dev_id < 0)
 209                 return -ENODEV;
 210
 211         type_name = NULL;
 212         if (dev_id == DEV_ID_MAX1668)
 213                 type_name = "max1668";
 214         else if (dev_id == DEV_ID_MAX1805)
 215                 type_name = "max1805";
 216         else if (dev_id == DEV_ID_MAX1989)
 217                 type_name = "max1989";
 218
 219         if (!type_name)
 220                 return -ENODEV;
 221
 222         strscpy(info->type, type_name, I2C_NAME_SIZE);
 223
 224         return 0;
 225 }
 226
 227 /* regmap */
 228
 229 static int max1668_reg_read(void *context, unsigned int reg, unsigned int *val)
 230 {
 231         int ret;
 232
 233         ret = i2c_smbus_read_byte_data(context, reg);
 234         if (ret < 0)
 235                 return ret;
 236
 237         *val = ret;
 238         return 0;
 239 }
 240
 241 static int max1668_reg_write(void *context, unsigned int reg, unsigned int val)
 242 {
 243         return i2c_smbus_write_byte_data(context, reg + 11, val);
 244 }
 245
 246 static bool max1668_regmap_is_volatile(struct device *dev, unsigned int reg)
 247 {
 248         return reg <= MAX1668_REG_STAT2;
 249 }
 250
 251 static bool max1668_regmap_is_writeable(struct device *dev, unsigned int reg)
 252 {
 253         return reg > MAX1668_REG_STAT2 && reg <= MAX1668_REG_LIML(4);
 254 }
 255
 256 static const struct regmap_config max1668_regmap_config = {
 257         .reg_bits = 8,
 258         .val_bits = 8,
 259         .cache_type = REGCACHE_MAPLE,
 260         .volatile_reg = max1668_regmap_is_volatile,
 261         .writeable_reg = max1668_regmap_is_writeable,
 262 };
 263
 264 static const struct regmap_bus max1668_regmap_bus = {
 265         .reg_write = max1668_reg_write,
 266         .reg_read = max1668_reg_read,
 267 };
 268
 269 static int max1668_probe(struct i2c_client *client)
 270 {
 271         struct i2c_adapter *adapter = client->adapter;
 272         struct device *dev = &client->dev;
 273         struct device *hwmon_dev;
 274         struct max1668_data *data;
 275
 276         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 277                 return -ENODEV;
 278
 279         data = devm_kzalloc(dev, sizeof(struct max1668_data), GFP_KERNEL);
 280         if (!data)
 281                 return -ENOMEM;
 282
 283         data->regmap = devm_regmap_init(dev, &max1668_regmap_bus, client,
 284                                         &max1668_regmap_config);
 285         if (IS_ERR(data->regmap))
 286                 return PTR_ERR(data->regmap);
 287
 288         data->channels = (uintptr_t)i2c_get_match_data(client);
 289
 290         hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
 291                                                          &max1668_chip_info, NULL);
 292         return PTR_ERR_OR_ZERO(hwmon_dev);
 293 }
 294
 295 static const struct i2c_device_id max1668_id[] = {
 296         { "max1668", 5 },
 297         { "max1805", 3 },
 298         { "max1989", 5 },
 299         { }
 300 };
 301 MODULE_DEVICE_TABLE(i2c, max1668_id);
 302
 303 /* This is the driver that will be inserted */
 304 static struct i2c_driver max1668_driver = {
 305         .class = I2C_CLASS_HWMON,
 306         .driver = {
 307                   .name = "max1668",
 308                   },
 309         .probe = max1668_probe,
 310         .id_table = max1668_id,
 311         .detect = max1668_detect,
 312         .address_list = max1668_addr_list,
 313 };
 314
 315 module_i2c_driver(max1668_driver);
 316
 317 MODULE_AUTHOR("David George <david.george@ska.ac.za>");
 318 MODULE_DESCRIPTION("MAX1668 remote temperature sensor driver");
 319 MODULE_LICENSE("GPL");