LXR linux/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
  36static 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
  57static 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
  81static 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
 115static 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
 148static const struct i2c_device_id ltc3815_id[] = {
 149        {"ltc3815", 0},
 150        { }
 151};
 152MODULE_DEVICE_TABLE(i2c, ltc3815_id);
 153
 154static 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
 184static 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
 202static 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
 211module_i2c_driver(ltc3815_driver);
 212
 213MODULE_AUTHOR("Guenter Roeck");
 214MODULE_DESCRIPTION("PMBus driver for LTC3815");
 215MODULE_LICENSE("GPL");
 216