drivers/hwmon/sg2042-mcu.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2024 Inochi Amaoto <inochiama@outlook.com>
   4  *
   5  * Sophgo power control mcu for SG2042
   6  */
   7
   8 #include <linux/cleanup.h>
   9 #include <linux/debugfs.h>
  10 #include <linux/err.h>
  11 #include <linux/hwmon.h>
  12 #include <linux/i2c.h>
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/mutex.h>
  16
  17 /* fixed MCU registers */
  18 #define REG_BOARD_TYPE                          0x00
  19 #define REG_MCU_FIRMWARE_VERSION                0x01
  20 #define REG_PCB_VERSION                         0x02
  21 #define REG_PWR_CTRL                            0x03
  22 #define REG_SOC_TEMP                            0x04
  23 #define REG_BOARD_TEMP                          0x05
  24 #define REG_RST_COUNT                           0x0a
  25 #define REG_UPTIME                              0x0b
  26 #define REG_RESET_REASON                        0x0d
  27 #define REG_MCU_TYPE                            0x18
  28 #define REG_REPOWER_POLICY                      0x65
  29 #define REG_CRITICAL_TEMP                       0x66
  30 #define REG_REPOWER_TEMP                        0x67
  31
  32 #define REPOWER_POLICY_REBOOT                   1
  33 #define REPOWER_POLICY_KEEP_OFF                 2
  34
  35 #define MCU_POWER_MAX                           0xff
  36
  37 #define DEFINE_MCU_DEBUG_ATTR(_name, _reg, _format)                     \
  38         static int _name##_show(struct seq_file *seqf,                  \
  39                                     void *unused)                       \
  40         {                                                               \
  41                 struct sg2042_mcu_data *mcu = seqf->private;            \
  42                 int ret;                                                \
  43                 ret = i2c_smbus_read_byte_data(mcu->client, (_reg));    \
  44                 if (ret < 0)                                            \
  45                         return ret;                                     \
  46                 seq_printf(seqf, _format "\n", ret);                    \
  47                 return 0;                                               \
  48         }                                                               \
  49         DEFINE_SHOW_ATTRIBUTE(_name)                                    \
  50
  51 struct sg2042_mcu_data {
  52         struct i2c_client       *client;
  53         struct dentry           *debugfs;
  54         struct mutex            mutex;
  55 };
  56
  57 static struct dentry *sgmcu_debugfs;
  58
  59 static ssize_t reset_count_show(struct device *dev,
  60                                 struct device_attribute *attr,
  61                                 char *buf)
  62 {
  63         struct sg2042_mcu_data *mcu = dev_get_drvdata(dev);
  64         int ret;
  65
  66         ret = i2c_smbus_read_byte_data(mcu->client, REG_RST_COUNT);
  67         if (ret < 0)
  68                 return ret;
  69
  70         return sprintf(buf, "%d\n", ret);
  71 }
  72
  73 static ssize_t uptime_show(struct device *dev,
  74                            struct device_attribute *attr,
  75                            char *buf)
  76 {
  77         struct sg2042_mcu_data *mcu = dev_get_drvdata(dev);
  78         u8 time_val[2];
  79         int ret;
  80
  81         ret = i2c_smbus_read_i2c_block_data(mcu->client, REG_UPTIME,
  82                                             sizeof(time_val), time_val);
  83         if (ret < 0)
  84                 return ret;
  85
  86         return sprintf(buf, "%d\n",
  87                        (time_val[0]) | (time_val[1] << 8));
  88 }
  89
  90 static ssize_t reset_reason_show(struct device *dev,
  91                                  struct device_attribute *attr,
  92                                  char *buf)
  93 {
  94         struct sg2042_mcu_data *mcu = dev_get_drvdata(dev);
  95         int ret;
  96
  97         ret = i2c_smbus_read_byte_data(mcu->client, REG_RESET_REASON);
  98         if (ret < 0)
  99                 return ret;
 100
 101         return sprintf(buf, "0x%02x\n", ret);
 102 }
 103
 104 static ssize_t repower_policy_show(struct device *dev,
 105                                    struct device_attribute *attr,
 106                                    char *buf)
 107 {
 108         struct sg2042_mcu_data *mcu = dev_get_drvdata(dev);
 109         int ret;
 110         const char *action;
 111
 112         ret = i2c_smbus_read_byte_data(mcu->client, REG_REPOWER_POLICY);
 113         if (ret < 0)
 114                 return ret;
 115
 116         if (ret == REPOWER_POLICY_REBOOT)
 117                 action = "repower";
 118         else if (ret == REPOWER_POLICY_KEEP_OFF)
 119                 action = "keep";
 120         else
 121                 action = "unknown";
 122
 123         return sprintf(buf, "%s\n", action);
 124 }
 125
 126 static ssize_t repower_policy_store(struct device *dev,
 127                                     struct device_attribute *attr,
 128                                     const char *buf, size_t count)
 129 {
 130         struct sg2042_mcu_data *mcu = dev_get_drvdata(dev);
 131         u8 value;
 132         int ret;
 133
 134         if (sysfs_streq("repower", buf))
 135                 value = REPOWER_POLICY_REBOOT;
 136         else if (sysfs_streq("keep", buf))
 137                 value = REPOWER_POLICY_KEEP_OFF;
 138         else
 139                 return -EINVAL;
 140
 141         ret = i2c_smbus_write_byte_data(mcu->client,
 142                                         REG_REPOWER_POLICY, value);
 143         if (ret < 0)
 144                 return ret;
 145
 146         return count;
 147 }
 148
 149 static DEVICE_ATTR_RO(reset_count);
 150 static DEVICE_ATTR_RO(uptime);
 151 static DEVICE_ATTR_RO(reset_reason);
 152 static DEVICE_ATTR_RW(repower_policy);
 153
 154 DEFINE_MCU_DEBUG_ATTR(firmware_version, REG_MCU_FIRMWARE_VERSION, "0x%02x");
 155 DEFINE_MCU_DEBUG_ATTR(pcb_version, REG_PCB_VERSION, "0x%02x");
 156 DEFINE_MCU_DEBUG_ATTR(board_type, REG_BOARD_TYPE, "0x%02x");
 157 DEFINE_MCU_DEBUG_ATTR(mcu_type, REG_MCU_TYPE, "%d");
 158
 159 static struct attribute *sg2042_mcu_attrs[] = {
 160         &dev_attr_reset_count.attr,
 161         &dev_attr_uptime.attr,
 162         &dev_attr_reset_reason.attr,
 163         &dev_attr_repower_policy.attr,
 164         NULL
 165 };
 166
 167 static const struct attribute_group sg2042_mcu_attr_group = {
 168         .attrs  = sg2042_mcu_attrs,
 169 };
 170
 171 static const struct attribute_group *sg2042_mcu_groups[] = {
 172         &sg2042_mcu_attr_group,
 173         NULL
 174 };
 175
 176 static const struct hwmon_channel_info * const sg2042_mcu_info[] = {
 177         HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
 178         HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_CRIT |
 179                                         HWMON_T_CRIT_HYST,
 180                                  HWMON_T_INPUT),
 181         NULL
 182 };
 183
 184 static int sg2042_mcu_read(struct device *dev,
 185                            enum hwmon_sensor_types type,
 186                            u32 attr, int channel, long *val)
 187 {
 188         struct sg2042_mcu_data *mcu = dev_get_drvdata(dev);
 189         int tmp;
 190         u8 reg;
 191
 192         switch (attr) {
 193         case hwmon_temp_input:
 194                 reg = channel ? REG_BOARD_TEMP : REG_SOC_TEMP;
 195                 break;
 196         case hwmon_temp_crit:
 197                 reg = REG_CRITICAL_TEMP;
 198                 break;
 199         case hwmon_temp_crit_hyst:
 200                 reg = REG_REPOWER_TEMP;
 201                 break;
 202         default:
 203                 return -EOPNOTSUPP;
 204         }
 205
 206         tmp = i2c_smbus_read_byte_data(mcu->client, reg);
 207         if (tmp < 0)
 208                 return tmp;
 209         *val = tmp * 1000;
 210
 211         return 0;
 212 }
 213
 214 static int sg2042_mcu_write(struct device *dev,
 215                             enum hwmon_sensor_types type,
 216                             u32 attr, int channel, long val)
 217 {
 218         struct sg2042_mcu_data *mcu = dev_get_drvdata(dev);
 219         int temp = val / 1000;
 220         int hyst_temp, crit_temp;
 221         u8 reg;
 222
 223         temp = clamp_val(temp, 0, MCU_POWER_MAX);
 224
 225         guard(mutex)(&mcu->mutex);
 226
 227         switch (attr) {
 228         case hwmon_temp_crit:
 229                 hyst_temp = i2c_smbus_read_byte_data(mcu->client,
 230                                                      REG_REPOWER_TEMP);
 231                 if (hyst_temp < 0)
 232                         return hyst_temp;
 233
 234                 crit_temp = temp;
 235                 reg = REG_CRITICAL_TEMP;
 236                 break;
 237         case hwmon_temp_crit_hyst:
 238                 crit_temp = i2c_smbus_read_byte_data(mcu->client,
 239                                                      REG_CRITICAL_TEMP);
 240                 if (crit_temp < 0)
 241                         return crit_temp;
 242
 243                 hyst_temp = temp;
 244                 reg = REG_REPOWER_TEMP;
 245                 break;
 246         default:
 247                 return -EOPNOTSUPP;
 248         }
 249
 250         /*
 251          * ensure hyst_temp is smaller to avoid MCU from
 252          * keeping triggering repower event.
 253          */
 254         if (crit_temp < hyst_temp)
 255                 return -EINVAL;
 256
 257         return i2c_smbus_write_byte_data(mcu->client, reg, temp);
 258 }
 259
 260 static umode_t sg2042_mcu_is_visible(const void *_data,
 261                                      enum hwmon_sensor_types type,
 262                                      u32 attr, int channel)
 263 {
 264         switch (type) {
 265         case hwmon_temp:
 266                 switch (attr) {
 267                 case hwmon_temp_input:
 268                         return 0444;
 269                 case hwmon_temp_crit:
 270                 case hwmon_temp_crit_hyst:
 271                         if (channel == 0)
 272                                 return 0644;
 273                         break;
 274                 default:
 275                         break;
 276                 }
 277                 break;
 278         default:
 279                         break;
 280         }
 281         return 0;
 282 }
 283
 284 static const struct hwmon_ops sg2042_mcu_ops = {
 285         .is_visible = sg2042_mcu_is_visible,
 286         .read = sg2042_mcu_read,
 287         .write = sg2042_mcu_write,
 288 };
 289
 290 static const struct hwmon_chip_info sg2042_mcu_chip_info = {
 291         .ops = &sg2042_mcu_ops,
 292         .info = sg2042_mcu_info,
 293 };
 294
 295 static void sg2042_mcu_debugfs_init(struct sg2042_mcu_data *mcu,
 296                                     struct device *dev)
 297 {
 298         mcu->debugfs = debugfs_create_dir(dev_name(dev), sgmcu_debugfs);
 299
 300         debugfs_create_file("firmware_version", 0444, mcu->debugfs,
 301                             mcu, &firmware_version_fops);
 302         debugfs_create_file("pcb_version", 0444, mcu->debugfs, mcu,
 303                             &pcb_version_fops);
 304         debugfs_create_file("mcu_type", 0444, mcu->debugfs, mcu,
 305                             &mcu_type_fops);
 306         debugfs_create_file("board_type", 0444, mcu->debugfs, mcu,
 307                             &board_type_fops);
 308 }
 309
 310 static int sg2042_mcu_i2c_probe(struct i2c_client *client)
 311 {
 312         struct device *dev = &client->dev;
 313         struct sg2042_mcu_data *mcu;
 314         struct device *hwmon_dev;
 315
 316         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 317                                                 I2C_FUNC_SMBUS_BLOCK_DATA))
 318                 return -ENODEV;
 319
 320         mcu = devm_kmalloc(dev, sizeof(*mcu), GFP_KERNEL);
 321         if (!mcu)
 322                 return -ENOMEM;
 323
 324         mutex_init(&mcu->mutex);
 325         mcu->client = client;
 326
 327         i2c_set_clientdata(client, mcu);
 328
 329         hwmon_dev = devm_hwmon_device_register_with_info(dev, "sg2042_mcu",
 330                                                          mcu,
 331                                                          &sg2042_mcu_chip_info,
 332                                                          NULL);
 333         if (IS_ERR(hwmon_dev))
 334                 return PTR_ERR(hwmon_dev);
 335
 336         sg2042_mcu_debugfs_init(mcu, dev);
 337
 338         return 0;
 339 }
 340
 341 static void sg2042_mcu_i2c_remove(struct i2c_client *client)
 342 {
 343         struct sg2042_mcu_data *mcu = i2c_get_clientdata(client);
 344
 345         debugfs_remove_recursive(mcu->debugfs);
 346 }
 347
 348 static const struct i2c_device_id sg2042_mcu_id[] = {
 349         { "sg2042-hwmon-mcu" },
 350         { }
 351 };
 352 MODULE_DEVICE_TABLE(i2c, sg2042_mcu_id);
 353
 354 static const struct of_device_id sg2042_mcu_of_id[] = {
 355         { .compatible = "sophgo,sg2042-hwmon-mcu" },
 356         {},
 357 };
 358 MODULE_DEVICE_TABLE(of, sg2042_mcu_of_id);
 359
 360 static struct i2c_driver sg2042_mcu_driver = {
 361         .driver = {
 362                 .name = "sg2042-mcu",
 363                 .of_match_table = sg2042_mcu_of_id,
 364                 .dev_groups = sg2042_mcu_groups,
 365         },
 366         .probe = sg2042_mcu_i2c_probe,
 367         .remove = sg2042_mcu_i2c_remove,
 368         .id_table = sg2042_mcu_id,
 369 };
 370
 371 static int __init sg2042_mcu_init(void)
 372 {
 373         sgmcu_debugfs = debugfs_create_dir("sg2042-mcu", NULL);
 374         return i2c_add_driver(&sg2042_mcu_driver);
 375 }
 376
 377 static void __exit sg2042_mcu_exit(void)
 378 {
 379         debugfs_remove_recursive(sgmcu_debugfs);
 380         i2c_del_driver(&sg2042_mcu_driver);
 381 }
 382
 383 module_init(sg2042_mcu_init);
 384 module_exit(sg2042_mcu_exit);
 385
 386 MODULE_AUTHOR("Inochi Amaoto <inochiama@outlook.com>");
 387 MODULE_DESCRIPTION("MCU I2C driver for SG2042 soc platform");
 388 MODULE_LICENSE("GPL");