drivers/hwmon/pmbus/ltc3815.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Hardware monitoring driver for LTC3815
   4  *
   5  * Copyright (c) 2015 Linear Technology
   6  * Copyright (c) 2015 Guenter Roeck
   7  */
   8
   9 #include <linux/err.h>
  10 #include <linux/i2c.h>
  11 #include <linux/init.h>
  12 #include <linux/jiffies.h>
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include "pmbus.h"
  16
  17 #define LTC3815_MFR_IOUT_PEAK   0xd7
  18 #define LTC3815_MFR_VOUT_PEAK   0xdd
  19 #define LTC3815_MFR_VIN_PEAK    0xde
  20 #define LTC3815_MFR_TEMP_PEAK   0xdf
  21 #define LTC3815_MFR_IIN_PEAK    0xe1
  22 #define LTC3815_MFR_SPECIAL_ID  0xe7
  23
  24 #define LTC3815_ID              0x8000
  25 #define LTC3815_ID_MASK         0xff00
  26
  27 static int ltc3815_read_byte_data(struct i2c_client *client, int page, int reg)
  28 {
  29         int ret;
  30
  31         switch (reg) {
  32         case PMBUS_VOUT_MODE:
  33                 /*
  34                  * The chip returns 0x3e, suggesting VID mode with manufacturer
  35                  * specific VID codes. Since the output voltage is reported
  36                  * with a LSB of 0.5mV, override and report direct mode with
  37                  * appropriate coefficients.
  38                  */
  39                 ret = 0x40;
  40                 break;
  41         default:
  42                 ret = -ENODATA;
  43                 break;
  44         }
  45         return ret;
  46 }
  47
  48 static int ltc3815_write_byte(struct i2c_client *client, int page, u8 reg)
  49 {
  50         int ret;
  51
  52         switch (reg) {
  53         case PMBUS_CLEAR_FAULTS:
  54                 /*
  55                  * LTC3815 does not support the CLEAR_FAULTS command.
  56                  * Emulate it by clearing the status register.
  57                  */
  58                 ret = pmbus_read_word_data(client, 0, 0xff, PMBUS_STATUS_WORD);
  59                 if (ret > 0) {
  60                         pmbus_write_word_data(client, 0, PMBUS_STATUS_WORD,
  61                                               ret);
  62                         ret = 0;
  63                 }
  64                 break;
  65         default:
  66                 ret = -ENODATA;
  67                 break;
  68         }
  69         return ret;
  70 }
  71
  72 static int ltc3815_read_word_data(struct i2c_client *client, int page,
  73                                   int phase, int reg)
  74 {
  75         int ret;
  76
  77         switch (reg) {
  78         case PMBUS_VIRT_READ_VIN_MAX:
  79                 ret = pmbus_read_word_data(client, page, phase,
  80                                            LTC3815_MFR_VIN_PEAK);
  81                 break;
  82         case PMBUS_VIRT_READ_VOUT_MAX:
  83                 ret = pmbus_read_word_data(client, page, phase,
  84                                            LTC3815_MFR_VOUT_PEAK);
  85                 break;
  86         case PMBUS_VIRT_READ_TEMP_MAX:
  87                 ret = pmbus_read_word_data(client, page, phase,
  88                                            LTC3815_MFR_TEMP_PEAK);
  89                 break;
  90         case PMBUS_VIRT_READ_IOUT_MAX:
  91                 ret = pmbus_read_word_data(client, page, phase,
  92                                            LTC3815_MFR_IOUT_PEAK);
  93                 break;
  94         case PMBUS_VIRT_READ_IIN_MAX:
  95                 ret = pmbus_read_word_data(client, page, phase,
  96                                            LTC3815_MFR_IIN_PEAK);
  97                 break;
  98         case PMBUS_VIRT_RESET_VOUT_HISTORY:
  99         case PMBUS_VIRT_RESET_VIN_HISTORY:
 100         case PMBUS_VIRT_RESET_TEMP_HISTORY:
 101         case PMBUS_VIRT_RESET_IOUT_HISTORY:
 102         case PMBUS_VIRT_RESET_IIN_HISTORY:
 103                 ret = 0;
 104                 break;
 105         default:
 106                 ret = -ENODATA;
 107                 break;
 108         }
 109         return ret;
 110 }
 111
 112 static int ltc3815_write_word_data(struct i2c_client *client, int page,
 113                                    int reg, u16 word)
 114 {
 115         int ret;
 116
 117         switch (reg) {
 118         case PMBUS_VIRT_RESET_IIN_HISTORY:
 119                 ret = pmbus_write_word_data(client, page,
 120                                             LTC3815_MFR_IIN_PEAK, 0);
 121                 break;
 122         case PMBUS_VIRT_RESET_IOUT_HISTORY:
 123                 ret = pmbus_write_word_data(client, page,
 124                                             LTC3815_MFR_IOUT_PEAK, 0);
 125                 break;
 126         case PMBUS_VIRT_RESET_VOUT_HISTORY:
 127                 ret = pmbus_write_word_data(client, page,
 128                                             LTC3815_MFR_VOUT_PEAK, 0);
 129                 break;
 130         case PMBUS_VIRT_RESET_VIN_HISTORY:
 131                 ret = pmbus_write_word_data(client, page,
 132                                             LTC3815_MFR_VIN_PEAK, 0);
 133                 break;
 134         case PMBUS_VIRT_RESET_TEMP_HISTORY:
 135                 ret = pmbus_write_word_data(client, page,
 136                                             LTC3815_MFR_TEMP_PEAK, 0);
 137                 break;
 138         default:
 139                 ret = -ENODATA;
 140                 break;
 141         }
 142         return ret;
 143 }
 144
 145 static const struct i2c_device_id ltc3815_id[] = {
 146         {"ltc3815", 0},
 147         { }
 148 };
 149 MODULE_DEVICE_TABLE(i2c, ltc3815_id);
 150
 151 static struct pmbus_driver_info ltc3815_info = {
 152         .pages = 1,
 153         .format[PSC_VOLTAGE_IN] = direct,
 154         .format[PSC_VOLTAGE_OUT] = direct,
 155         .format[PSC_CURRENT_IN] = direct,
 156         .format[PSC_CURRENT_OUT] = direct,
 157         .format[PSC_TEMPERATURE] = direct,
 158         .m[PSC_VOLTAGE_IN] = 250,
 159         .b[PSC_VOLTAGE_IN] = 0,
 160         .R[PSC_VOLTAGE_IN] = 0,
 161         .m[PSC_VOLTAGE_OUT] = 2,
 162         .b[PSC_VOLTAGE_OUT] = 0,
 163         .R[PSC_VOLTAGE_OUT] = 3,
 164         .m[PSC_CURRENT_IN] = 1,
 165         .b[PSC_CURRENT_IN] = 0,
 166         .R[PSC_CURRENT_IN] = 2,
 167         .m[PSC_CURRENT_OUT] = 1,
 168         .b[PSC_CURRENT_OUT] = 0,
 169         .R[PSC_CURRENT_OUT] = 2,
 170         .m[PSC_TEMPERATURE] = 1,
 171         .b[PSC_TEMPERATURE] = 0,
 172         .R[PSC_TEMPERATURE] = 0,
 173         .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN | PMBUS_HAVE_VOUT |
 174                 PMBUS_HAVE_IOUT | PMBUS_HAVE_TEMP,
 175         .read_byte_data = ltc3815_read_byte_data,
 176         .read_word_data = ltc3815_read_word_data,
 177         .write_byte = ltc3815_write_byte,
 178         .write_word_data = ltc3815_write_word_data,
 179 };
 180
 181 static int ltc3815_probe(struct i2c_client *client)
 182 {
 183         int chip_id;
 184
 185         if (!i2c_check_functionality(client->adapter,
 186                                      I2C_FUNC_SMBUS_READ_WORD_DATA))
 187                 return -ENODEV;
 188
 189         chip_id = i2c_smbus_read_word_data(client, LTC3815_MFR_SPECIAL_ID);
 190         if (chip_id < 0)
 191                 return chip_id;
 192         if ((chip_id & LTC3815_ID_MASK) != LTC3815_ID)
 193                 return -ENODEV;
 194
 195         return pmbus_do_probe(client, &ltc3815_info);
 196 }
 197
 198 static struct i2c_driver ltc3815_driver = {
 199         .driver = {
 200                    .name = "ltc3815",
 201                    },
 202         .probe_new = ltc3815_probe,
 203         .id_table = ltc3815_id,
 204 };
 205
 206 module_i2c_driver(ltc3815_driver);
 207
 208 MODULE_AUTHOR("Guenter Roeck");
 209 MODULE_DESCRIPTION("PMBus driver for LTC3815");
 210 MODULE_LICENSE("GPL");