drivers/hwmon/pmbus.c

   1 /*
   2  * Hardware monitoring driver for PMBus devices
   3  *
   4  * Copyright (c) 2010, 2011 Ericsson AB.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20
  21 #include <linux/kernel.h>
  22 #include <linux/module.h>
  23 #include <linux/init.h>
  24 #include <linux/err.h>
  25 #include <linux/slab.h>
  26 #include <linux/mutex.h>
  27 #include <linux/i2c.h>
  28 #include "pmbus.h"
  29
  30 /*
  31  * Find sensor groups and status registers on each page.
  32  */
  33 static void pmbus_find_sensor_groups(struct i2c_client *client,
  34                                      struct pmbus_driver_info *info)
  35 {
  36         int page;
  37
  38         /* Sensors detected on page 0 only */
  39         if (pmbus_check_word_register(client, 0, PMBUS_READ_VIN))
  40                 info->func[0] |= PMBUS_HAVE_VIN;
  41         if (pmbus_check_word_register(client, 0, PMBUS_READ_VCAP))
  42                 info->func[0] |= PMBUS_HAVE_VCAP;
  43         if (pmbus_check_word_register(client, 0, PMBUS_READ_IIN))
  44                 info->func[0] |= PMBUS_HAVE_IIN;
  45         if (pmbus_check_word_register(client, 0, PMBUS_READ_PIN))
  46                 info->func[0] |= PMBUS_HAVE_PIN;
  47         if (info->func[0]
  48             && pmbus_check_byte_register(client, 0, PMBUS_STATUS_INPUT))
  49                 info->func[0] |= PMBUS_HAVE_STATUS_INPUT;
  50         if (pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_1)) {
  51                 info->func[0] |= PMBUS_HAVE_FAN12;
  52                 if (pmbus_check_byte_register(client, 0, PMBUS_STATUS_FAN_12))
  53                         info->func[0] |= PMBUS_HAVE_STATUS_FAN12;
  54         }
  55         if (pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_3)) {
  56                 info->func[0] |= PMBUS_HAVE_FAN34;
  57                 if (pmbus_check_byte_register(client, 0, PMBUS_STATUS_FAN_34))
  58                         info->func[0] |= PMBUS_HAVE_STATUS_FAN34;
  59         }
  60         if (pmbus_check_word_register(client, 0, PMBUS_READ_TEMPERATURE_1)) {
  61                 info->func[0] |= PMBUS_HAVE_TEMP;
  62                 if (pmbus_check_byte_register(client, 0,
  63                                               PMBUS_STATUS_TEMPERATURE))
  64                         info->func[0] |= PMBUS_HAVE_STATUS_TEMP;
  65         }
  66
  67         /* Sensors detected on all pages */
  68         for (page = 0; page < info->pages; page++) {
  69                 if (pmbus_check_word_register(client, page, PMBUS_READ_VOUT)) {
  70                         info->func[page] |= PMBUS_HAVE_VOUT;
  71                         if (pmbus_check_byte_register(client, page,
  72                                                       PMBUS_STATUS_VOUT))
  73                                 info->func[page] |= PMBUS_HAVE_STATUS_VOUT;
  74                 }
  75                 if (pmbus_check_word_register(client, page, PMBUS_READ_IOUT)) {
  76                         info->func[page] |= PMBUS_HAVE_IOUT;
  77                         if (pmbus_check_byte_register(client, 0,
  78                                                       PMBUS_STATUS_IOUT))
  79                                 info->func[page] |= PMBUS_HAVE_STATUS_IOUT;
  80                 }
  81                 if (pmbus_check_word_register(client, page, PMBUS_READ_POUT))
  82                         info->func[page] |= PMBUS_HAVE_POUT;
  83         }
  84 }
  85
  86 /*
  87  * Identify chip parameters.
  88  */
  89 static int pmbus_identify(struct i2c_client *client,
  90                           struct pmbus_driver_info *info)
  91 {
  92         if (!info->pages) {
  93                 /*
  94                  * Check if the PAGE command is supported. If it is,
  95                  * keep setting the page number until it fails or until the
  96                  * maximum number of pages has been reached. Assume that
  97                  * this is the number of pages supported by the chip.
  98                  */
  99                 if (pmbus_check_byte_register(client, 0, PMBUS_PAGE)) {
 100                         int page;
 101
 102                         for (page = 1; page < PMBUS_PAGES; page++) {
 103                                 if (pmbus_set_page(client, page) < 0)
 104                                         break;
 105                         }
 106                         pmbus_set_page(client, 0);
 107                         info->pages = page;
 108                 } else {
 109                         info->pages = 1;
 110                 }
 111         }
 112
 113         /*
 114          * We should check if the COEFFICIENTS register is supported.
 115          * If it is, and the chip is configured for direct mode, we can read
 116          * the coefficients from the chip, one set per group of sensor
 117          * registers.
 118          *
 119          * To do this, we will need access to a chip which actually supports the
 120          * COEFFICIENTS command, since the command is too complex to implement
 121          * without testing it.
 122          */
 123
 124         /* Try to find sensor groups  */
 125         pmbus_find_sensor_groups(client, info);
 126
 127         return 0;
 128 }
 129
 130 static int pmbus_probe(struct i2c_client *client,
 131                        const struct i2c_device_id *id)
 132 {
 133         struct pmbus_driver_info *info;
 134         int ret;
 135
 136         info = kzalloc(sizeof(struct pmbus_driver_info), GFP_KERNEL);
 137         if (!info)
 138                 return -ENOMEM;
 139
 140         info->pages = id->driver_data;
 141         info->identify = pmbus_identify;
 142
 143         ret = pmbus_do_probe(client, id, info);
 144         if (ret < 0)
 145                 goto out;
 146         return 0;
 147
 148 out:
 149         kfree(info);
 150         return ret;
 151 }
 152
 153 static int pmbus_remove(struct i2c_client *client)
 154 {
 155         int ret;
 156         const struct pmbus_driver_info *info;
 157
 158         info = pmbus_get_driver_info(client);
 159         ret = pmbus_do_remove(client);
 160         kfree(info);
 161         return ret;
 162 }
 163
 164 /*
 165  * Use driver_data to set the number of pages supported by the chip.
 166  */
 167 static const struct i2c_device_id pmbus_id[] = {
 168         {"bmr450", 1},
 169         {"bmr451", 1},
 170         {"bmr453", 1},
 171         {"bmr454", 1},
 172         {"ltc2978", 8},
 173         {"pmbus", 0},
 174         {}
 175 };
 176
 177 MODULE_DEVICE_TABLE(i2c, pmbus_id);
 178
 179 /* This is the driver that will be inserted */
 180 static struct i2c_driver pmbus_driver = {
 181         .driver = {
 182                    .name = "pmbus",
 183                    },
 184         .probe = pmbus_probe,
 185         .remove = pmbus_remove,
 186         .id_table = pmbus_id,
 187 };
 188
 189 static int __init pmbus_init(void)
 190 {
 191         return i2c_add_driver(&pmbus_driver);
 192 }
 193
 194 static void __exit pmbus_exit(void)
 195 {
 196         i2c_del_driver(&pmbus_driver);
 197 }
 198
 199 MODULE_AUTHOR("Guenter Roeck");
 200 MODULE_DESCRIPTION("Generic PMBus driver");
 201 MODULE_LICENSE("GPL");
 202 module_init(pmbus_init);
 203 module_exit(pmbus_exit);