drivers/hwmon/pmbus/fsp-3y.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Hardware monitoring driver for FSP 3Y-Power PSUs
   4  *
   5  * Copyright (c) 2021 Václav Kubernát, CESNET
   6  *
   7  * This driver is mostly reverse engineered with the help of a tool called pmbus_peek written by
   8  * David Brownell (and later adopted by Jan Kundrát). The device has some sort of a timing issue
   9  * when switching pages, details are explained in the code. The driver support is limited. It
  10  * exposes only the values, that have been tested to work correctly. Unsupported values either
  11  * aren't supported by the devices or their encondings are unknown.
  12  */
  13
  14 #include <linux/delay.h>
  15 #include <linux/i2c.h>
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include "pmbus.h"
  19
  20 #define YM2151_PAGE_12V_LOG     0x00
  21 #define YM2151_PAGE_12V_REAL    0x00
  22 #define YM2151_PAGE_5VSB_LOG    0x01
  23 #define YM2151_PAGE_5VSB_REAL   0x20
  24 #define YH5151E_PAGE_12V_LOG    0x00
  25 #define YH5151E_PAGE_12V_REAL   0x00
  26 #define YH5151E_PAGE_5V_LOG     0x01
  27 #define YH5151E_PAGE_5V_REAL    0x10
  28 #define YH5151E_PAGE_3V3_LOG    0x02
  29 #define YH5151E_PAGE_3V3_REAL   0x11
  30
  31 enum chips {
  32         ym2151e,
  33         yh5151e
  34 };
  35
  36 struct fsp3y_data {
  37         struct pmbus_driver_info info;
  38         int chip;
  39         int page;
  40
  41         bool vout_linear_11;
  42 };
  43
  44 #define to_fsp3y_data(x) container_of(x, struct fsp3y_data, info)
  45
  46 static int page_log_to_page_real(int page_log, enum chips chip)
  47 {
  48         switch (chip) {
  49         case ym2151e:
  50                 switch (page_log) {
  51                 case YM2151_PAGE_12V_LOG:
  52                         return YM2151_PAGE_12V_REAL;
  53                 case YM2151_PAGE_5VSB_LOG:
  54                         return YM2151_PAGE_5VSB_REAL;
  55                 }
  56                 return -EINVAL;
  57         case yh5151e:
  58                 switch (page_log) {
  59                 case YH5151E_PAGE_12V_LOG:
  60                         return YH5151E_PAGE_12V_REAL;
  61                 case YH5151E_PAGE_5V_LOG:
  62                         return YH5151E_PAGE_5V_REAL;
  63                 case YH5151E_PAGE_3V3_LOG:
  64                         return YH5151E_PAGE_3V3_REAL;
  65                 }
  66                 return -EINVAL;
  67         }
  68
  69         return -EINVAL;
  70 }
  71
  72 static int set_page(struct i2c_client *client, int page_log)
  73 {
  74         const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
  75         struct fsp3y_data *data = to_fsp3y_data(info);
  76         int rv;
  77         int page_real;
  78
  79         if (page_log < 0)
  80                 return 0;
  81
  82         page_real = page_log_to_page_real(page_log, data->chip);
  83         if (page_real < 0)
  84                 return page_real;
  85
  86         if (data->page != page_real) {
  87                 rv = i2c_smbus_write_byte_data(client, PMBUS_PAGE, page_real);
  88                 if (rv < 0)
  89                         return rv;
  90
  91                 data->page = page_real;
  92
  93                 /*
  94                  * Testing showed that the device has a timing issue. After
  95                  * setting a page, it takes a while, before the device actually
  96                  * gives the correct values from the correct page. 20 ms was
  97                  * tested to be enough to not give wrong values (15 ms wasn't
  98                  * enough).
  99                  */
 100                 usleep_range(20000, 30000);
 101         }
 102
 103         return 0;
 104 }
 105
 106 static int fsp3y_read_byte_data(struct i2c_client *client, int page, int reg)
 107 {
 108         const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
 109         struct fsp3y_data *data = to_fsp3y_data(info);
 110         int rv;
 111
 112         /*
 113          * Inject an exponent for non-compliant YH5151-E.
 114          */
 115         if (data->vout_linear_11 && reg == PMBUS_VOUT_MODE)
 116                 return 0x1A;
 117
 118         rv = set_page(client, page);
 119         if (rv < 0)
 120                 return rv;
 121
 122         return i2c_smbus_read_byte_data(client, reg);
 123 }
 124
 125 static int fsp3y_read_word_data(struct i2c_client *client, int page, int phase, int reg)
 126 {
 127         const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
 128         struct fsp3y_data *data = to_fsp3y_data(info);
 129         int rv;
 130
 131         /*
 132          * This masks commands which weren't tested to work correctly. Some of
 133          * the masked commands return 0xFFFF. These would probably get tagged as
 134          * invalid by pmbus_core. Other ones do return values which might be
 135          * useful (that is, they are not 0xFFFF), but their encoding is unknown,
 136          * and so they are unsupported.
 137          */
 138         switch (reg) {
 139         case PMBUS_READ_FAN_SPEED_1:
 140         case PMBUS_READ_IIN:
 141         case PMBUS_READ_IOUT:
 142         case PMBUS_READ_PIN:
 143         case PMBUS_READ_POUT:
 144         case PMBUS_READ_TEMPERATURE_1:
 145         case PMBUS_READ_TEMPERATURE_2:
 146         case PMBUS_READ_TEMPERATURE_3:
 147         case PMBUS_READ_VIN:
 148         case PMBUS_READ_VOUT:
 149         case PMBUS_STATUS_WORD:
 150                 break;
 151         default:
 152                 return -ENXIO;
 153         }
 154
 155         rv = set_page(client, page);
 156         if (rv < 0)
 157                 return rv;
 158
 159         rv = i2c_smbus_read_word_data(client, reg);
 160         if (rv < 0)
 161                 return rv;
 162
 163         /*
 164          * Handle YH-5151E non-compliant linear11 vout voltage.
 165          */
 166         if (data->vout_linear_11 && reg == PMBUS_READ_VOUT)
 167                 rv = sign_extend32(rv, 10) & 0xffff;
 168
 169         return rv;
 170 }
 171
 172 static struct pmbus_driver_info fsp3y_info[] = {
 173         [ym2151e] = {
 174                 .pages = 2,
 175                 .func[YM2151_PAGE_12V_LOG] =
 176                         PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
 177                         PMBUS_HAVE_PIN | PMBUS_HAVE_POUT  |
 178                         PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 |
 179                         PMBUS_HAVE_VIN | PMBUS_HAVE_IIN |
 180                         PMBUS_HAVE_FAN12,
 181                 .func[YM2151_PAGE_5VSB_LOG] =
 182                         PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT,
 183                 .read_word_data = fsp3y_read_word_data,
 184                 .read_byte_data = fsp3y_read_byte_data,
 185         },
 186         [yh5151e] = {
 187                 .pages = 3,
 188                 .func[YH5151E_PAGE_12V_LOG] =
 189                         PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
 190                         PMBUS_HAVE_POUT  |
 191                         PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_TEMP3,
 192                 .func[YH5151E_PAGE_5V_LOG] =
 193                         PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
 194                         PMBUS_HAVE_POUT,
 195                 .func[YH5151E_PAGE_3V3_LOG] =
 196                         PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
 197                         PMBUS_HAVE_POUT,
 198                 .read_word_data = fsp3y_read_word_data,
 199                 .read_byte_data = fsp3y_read_byte_data,
 200         }
 201 };
 202
 203 static int fsp3y_detect(struct i2c_client *client)
 204 {
 205         int rv;
 206         u8 buf[I2C_SMBUS_BLOCK_MAX + 1];
 207
 208         rv = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, buf);
 209         if (rv < 0)
 210                 return rv;
 211
 212         buf[rv] = '\0';
 213
 214         if (rv == 8) {
 215                 if (!strcmp(buf, "YM-2151E"))
 216                         return ym2151e;
 217                 else if (!strcmp(buf, "YH-5151E"))
 218                         return yh5151e;
 219         }
 220
 221         dev_err(&client->dev, "Unsupported model %.*s\n", rv, buf);
 222         return -ENODEV;
 223 }
 224
 225 static const struct i2c_device_id fsp3y_id[] = {
 226         {"ym2151e", ym2151e},
 227         {"yh5151e", yh5151e},
 228         { }
 229 };
 230
 231 static int fsp3y_probe(struct i2c_client *client)
 232 {
 233         struct fsp3y_data *data;
 234         const struct i2c_device_id *id;
 235         int rv;
 236
 237         data = devm_kzalloc(&client->dev, sizeof(struct fsp3y_data), GFP_KERNEL);
 238         if (!data)
 239                 return -ENOMEM;
 240
 241         data->chip = fsp3y_detect(client);
 242         if (data->chip < 0)
 243                 return data->chip;
 244
 245         id = i2c_match_id(fsp3y_id, client);
 246         if (data->chip != id->driver_data)
 247                 dev_warn(&client->dev, "Device mismatch: Configured %s (%d), detected %d\n",
 248                          id->name, (int)id->driver_data, data->chip);
 249
 250         rv = i2c_smbus_read_byte_data(client, PMBUS_PAGE);
 251         if (rv < 0)
 252                 return rv;
 253         data->page = rv;
 254
 255         data->info = fsp3y_info[data->chip];
 256
 257         /*
 258          * YH-5151E sometimes reports vout in linear11 and sometimes in
 259          * linear16. This depends on the exact individual piece of hardware. One
 260          * YH-5151E can use linear16 and another might use linear11 instead.
 261          *
 262          * The format can be recognized by reading VOUT_MODE - if it doesn't
 263          * report a valid exponent, then vout uses linear11. Otherwise, the
 264          * device is compliant and uses linear16.
 265          */
 266         data->vout_linear_11 = false;
 267         if (data->chip == yh5151e) {
 268                 rv = i2c_smbus_read_byte_data(client, PMBUS_VOUT_MODE);
 269                 if (rv < 0)
 270                         return rv;
 271
 272                 if (rv == 0xFF)
 273                         data->vout_linear_11 = true;
 274         }
 275
 276         return pmbus_do_probe(client, &data->info);
 277 }
 278
 279 MODULE_DEVICE_TABLE(i2c, fsp3y_id);
 280
 281 static struct i2c_driver fsp3y_driver = {
 282         .driver = {
 283                    .name = "fsp3y",
 284                    },
 285         .probe = fsp3y_probe,
 286         .id_table = fsp3y_id
 287 };
 288
 289 module_i2c_driver(fsp3y_driver);
 290
 291 MODULE_AUTHOR("Václav Kubernát");
 292 MODULE_DESCRIPTION("PMBus driver for FSP/3Y-Power power supplies");
 293 MODULE_LICENSE("GPL");
 294 MODULE_IMPORT_NS("PMBUS");