linux/drivers/hwmon/pmbus/ltc3815.c
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   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
  27static 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
  48static 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
  72static 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
 112static 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
 145static const struct i2c_device_id ltc3815_id[] = {
 146        {"ltc3815", 0},
 147        { }
 148};
 149MODULE_DEVICE_TABLE(i2c, ltc3815_id);
 150
 151static 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
 181static 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
 198static struct i2c_driver ltc3815_driver = {
 199        .driver = {
 200                   .name = "ltc3815",
 201                   },
 202        .probe_new = ltc3815_probe,
 203        .id_table = ltc3815_id,
 204};
 205
 206module_i2c_driver(ltc3815_driver);
 207
 208MODULE_AUTHOR("Guenter Roeck");
 209MODULE_DESCRIPTION("PMBus driver for LTC3815");
 210MODULE_LICENSE("GPL");
 211MODULE_IMPORT_NS(PMBUS);
 212