drivers/hwmon/pmbus/ltc3815.c

   1 /*
   2  * Hardware monitoring driver for LTC3815
   3  *
   4  * Copyright (c) 2015 Linear Technology
   5  * Copyright (c) 2015 Guenter Roeck
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include <linux/err.h>
  19 #include <linux/i2c.h>
  20 #include <linux/init.h>
  21 #include <linux/jiffies.h>
  22 #include <linux/kernel.h>
  23 #include <linux/module.h>
  24 #include "pmbus.h"
  25
  26 #define LTC3815_MFR_IOUT_PEAK   0xd7
  27 #define LTC3815_MFR_VOUT_PEAK   0xdd
  28 #define LTC3815_MFR_VIN_PEAK    0xde
  29 #define LTC3815_MFR_TEMP_PEAK   0xdf
  30 #define LTC3815_MFR_IIN_PEAK    0xe1
  31 #define LTC3815_MFR_SPECIAL_ID  0xe7
  32
  33 #define LTC3815_ID              0x8000
  34 #define LTC3815_ID_MASK         0xff00
  35
  36 static int ltc3815_read_byte_data(struct i2c_client *client, int page, int reg)
  37 {
  38         int ret;
  39
  40         switch (reg) {
  41         case PMBUS_VOUT_MODE:
  42                 /*
  43                  * The chip returns 0x3e, suggesting VID mode with manufacturer
  44                  * specific VID codes. Since the output voltage is reported
  45                  * with a LSB of 0.5mV, override and report direct mode with
  46                  * appropriate coefficients.
  47                  */
  48                 ret = 0x40;
  49                 break;
  50         default:
  51                 ret = -ENODATA;
  52                 break;
  53         }
  54         return ret;
  55 }
  56
  57 static int ltc3815_write_byte(struct i2c_client *client, int page, u8 reg)
  58 {
  59         int ret;
  60
  61         switch (reg) {
  62         case PMBUS_CLEAR_FAULTS:
  63                 /*
  64                  * LTC3815 does not support the CLEAR_FAULTS command.
  65                  * Emulate it by clearing the status register.
  66                  */
  67                 ret = pmbus_read_word_data(client, 0, PMBUS_STATUS_WORD);
  68                 if (ret > 0) {
  69                         pmbus_write_word_data(client, 0, PMBUS_STATUS_WORD,
  70                                               ret);
  71                         ret = 0;
  72                 }
  73                 break;
  74         default:
  75                 ret = -ENODATA;
  76                 break;
  77         }
  78         return ret;
  79 }
  80
  81 static int ltc3815_read_word_data(struct i2c_client *client, int page, int reg)
  82 {
  83         int ret;
  84
  85         switch (reg) {
  86         case PMBUS_VIRT_READ_VIN_MAX:
  87                 ret = pmbus_read_word_data(client, page, LTC3815_MFR_VIN_PEAK);
  88                 break;
  89         case PMBUS_VIRT_READ_VOUT_MAX:
  90                 ret = pmbus_read_word_data(client, page, LTC3815_MFR_VOUT_PEAK);
  91                 break;
  92         case PMBUS_VIRT_READ_TEMP_MAX:
  93                 ret = pmbus_read_word_data(client, page, LTC3815_MFR_TEMP_PEAK);
  94                 break;
  95         case PMBUS_VIRT_READ_IOUT_MAX:
  96                 ret = pmbus_read_word_data(client, page, LTC3815_MFR_IOUT_PEAK);
  97                 break;
  98         case PMBUS_VIRT_READ_IIN_MAX:
  99                 ret = pmbus_read_word_data(client, page, LTC3815_MFR_IIN_PEAK);
 100                 break;
 101         case PMBUS_VIRT_RESET_VOUT_HISTORY:
 102         case PMBUS_VIRT_RESET_VIN_HISTORY:
 103         case PMBUS_VIRT_RESET_TEMP_HISTORY:
 104         case PMBUS_VIRT_RESET_IOUT_HISTORY:
 105         case PMBUS_VIRT_RESET_IIN_HISTORY:
 106                 ret = 0;
 107                 break;
 108         default:
 109                 ret = -ENODATA;
 110                 break;
 111         }
 112         return ret;
 113 }
 114
 115 static int ltc3815_write_word_data(struct i2c_client *client, int page,
 116                                    int reg, u16 word)
 117 {
 118         int ret;
 119
 120         switch (reg) {
 121         case PMBUS_VIRT_RESET_IIN_HISTORY:
 122                 ret = pmbus_write_word_data(client, page,
 123                                             LTC3815_MFR_IIN_PEAK, 0);
 124                 break;
 125         case PMBUS_VIRT_RESET_IOUT_HISTORY:
 126                 ret = pmbus_write_word_data(client, page,
 127                                             LTC3815_MFR_IOUT_PEAK, 0);
 128                 break;
 129         case PMBUS_VIRT_RESET_VOUT_HISTORY:
 130                 ret = pmbus_write_word_data(client, page,
 131                                             LTC3815_MFR_VOUT_PEAK, 0);
 132                 break;
 133         case PMBUS_VIRT_RESET_VIN_HISTORY:
 134                 ret = pmbus_write_word_data(client, page,
 135                                             LTC3815_MFR_VIN_PEAK, 0);
 136                 break;
 137         case PMBUS_VIRT_RESET_TEMP_HISTORY:
 138                 ret = pmbus_write_word_data(client, page,
 139                                             LTC3815_MFR_TEMP_PEAK, 0);
 140                 break;
 141         default:
 142                 ret = -ENODATA;
 143                 break;
 144         }
 145         return ret;
 146 }
 147
 148 static const struct i2c_device_id ltc3815_id[] = {
 149         {"ltc3815", 0},
 150         { }
 151 };
 152 MODULE_DEVICE_TABLE(i2c, ltc3815_id);
 153
 154 static struct pmbus_driver_info ltc3815_info = {
 155         .pages = 1,
 156         .format[PSC_VOLTAGE_IN] = direct,
 157         .format[PSC_VOLTAGE_OUT] = direct,
 158         .format[PSC_CURRENT_IN] = direct,
 159         .format[PSC_CURRENT_OUT] = direct,
 160         .format[PSC_TEMPERATURE] = direct,
 161         .m[PSC_VOLTAGE_IN] = 250,
 162         .b[PSC_VOLTAGE_IN] = 0,
 163         .R[PSC_VOLTAGE_IN] = 0,
 164         .m[PSC_VOLTAGE_OUT] = 2,
 165         .b[PSC_VOLTAGE_OUT] = 0,
 166         .R[PSC_VOLTAGE_OUT] = 3,
 167         .m[PSC_CURRENT_IN] = 1,
 168         .b[PSC_CURRENT_IN] = 0,
 169         .R[PSC_CURRENT_IN] = 2,
 170         .m[PSC_CURRENT_OUT] = 1,
 171         .b[PSC_CURRENT_OUT] = 0,
 172         .R[PSC_CURRENT_OUT] = 2,
 173         .m[PSC_TEMPERATURE] = 1,
 174         .b[PSC_TEMPERATURE] = 0,
 175         .R[PSC_TEMPERATURE] = 0,
 176         .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN | PMBUS_HAVE_VOUT |
 177                 PMBUS_HAVE_IOUT | PMBUS_HAVE_TEMP,
 178         .read_byte_data = ltc3815_read_byte_data,
 179         .read_word_data = ltc3815_read_word_data,
 180         .write_byte = ltc3815_write_byte,
 181         .write_word_data = ltc3815_write_word_data,
 182 };
 183
 184 static int ltc3815_probe(struct i2c_client *client,
 185                          const struct i2c_device_id *id)
 186 {
 187         int chip_id;
 188
 189         if (!i2c_check_functionality(client->adapter,
 190                                      I2C_FUNC_SMBUS_READ_WORD_DATA))
 191                 return -ENODEV;
 192
 193         chip_id = i2c_smbus_read_word_data(client, LTC3815_MFR_SPECIAL_ID);
 194         if (chip_id < 0)
 195                 return chip_id;
 196         if ((chip_id & LTC3815_ID_MASK) != LTC3815_ID)
 197                 return -ENODEV;
 198
 199         return pmbus_do_probe(client, id, &ltc3815_info);
 200 }
 201
 202 static struct i2c_driver ltc3815_driver = {
 203         .driver = {
 204                    .name = "ltc3815",
 205                    },
 206         .probe = ltc3815_probe,
 207         .remove = pmbus_do_remove,
 208         .id_table = ltc3815_id,
 209 };
 210
 211 module_i2c_driver(ltc3815_driver);
 212
 213 MODULE_AUTHOR("Guenter Roeck");
 214 MODULE_DESCRIPTION("PMBus driver for LTC3815");
 215 MODULE_LICENSE("GPL");