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_byte_register(client, 0, PMBUS_FAN_CONFIG_12) &&
  51             pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_1)) {
  52                 info->func[0] |= PMBUS_HAVE_FAN12;
  53                 if (pmbus_check_byte_register(client, 0, PMBUS_STATUS_FAN_12))
  54                         info->func[0] |= PMBUS_HAVE_STATUS_FAN12;
  55         }
  56         if (pmbus_check_byte_register(client, 0, PMBUS_FAN_CONFIG_34) &&
  57             pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_3)) {
  58                 info->func[0] |= PMBUS_HAVE_FAN34;
  59                 if (pmbus_check_byte_register(client, 0, PMBUS_STATUS_FAN_34))
  60                         info->func[0] |= PMBUS_HAVE_STATUS_FAN34;
  61         }
  62         if (pmbus_check_word_register(client, 0, PMBUS_READ_TEMPERATURE_1)) {
  63                 info->func[0] |= PMBUS_HAVE_TEMP;
  64                 if (pmbus_check_byte_register(client, 0,
  65                                               PMBUS_STATUS_TEMPERATURE))
  66                         info->func[0] |= PMBUS_HAVE_STATUS_TEMP;
  67         }
  68
  69         /* Sensors detected on all pages */
  70         for (page = 0; page < info->pages; page++) {
  71                 if (pmbus_check_word_register(client, page, PMBUS_READ_VOUT)) {
  72                         info->func[page] |= PMBUS_HAVE_VOUT;
  73                         if (pmbus_check_byte_register(client, page,
  74                                                       PMBUS_STATUS_VOUT))
  75                                 info->func[page] |= PMBUS_HAVE_STATUS_VOUT;
  76                 }
  77                 if (pmbus_check_word_register(client, page, PMBUS_READ_IOUT)) {
  78                         info->func[page] |= PMBUS_HAVE_IOUT;
  79                         if (pmbus_check_byte_register(client, 0,
  80                                                       PMBUS_STATUS_IOUT))
  81                                 info->func[page] |= PMBUS_HAVE_STATUS_IOUT;
  82                 }
  83                 if (pmbus_check_word_register(client, page, PMBUS_READ_POUT))
  84                         info->func[page] |= PMBUS_HAVE_POUT;
  85         }
  86 }
  87
  88 /*
  89  * Identify chip parameters.
  90  */
  91 static int pmbus_identify(struct i2c_client *client,
  92                           struct pmbus_driver_info *info)
  93 {
  94         if (!info->pages) {
  95                 /*
  96                  * Check if the PAGE command is supported. If it is,
  97                  * keep setting the page number until it fails or until the
  98                  * maximum number of pages has been reached. Assume that
  99                  * this is the number of pages supported by the chip.
 100                  */
 101                 if (pmbus_check_byte_register(client, 0, PMBUS_PAGE)) {
 102                         int page;
 103
 104                         for (page = 1; page < PMBUS_PAGES; page++) {
 105                                 if (pmbus_set_page(client, page) < 0)
 106                                         break;
 107                         }
 108                         pmbus_set_page(client, 0);
 109                         info->pages = page;
 110                 } else {
 111                         info->pages = 1;
 112                 }
 113         }
 114
 115         /*
 116          * We should check if the COEFFICIENTS register is supported.
 117          * If it is, and the chip is configured for direct mode, we can read
 118          * the coefficients from the chip, one set per group of sensor
 119          * registers.
 120          *
 121          * To do this, we will need access to a chip which actually supports the
 122          * COEFFICIENTS command, since the command is too complex to implement
 123          * without testing it.
 124          */
 125
 126         /* Try to find sensor groups  */
 127         pmbus_find_sensor_groups(client, info);
 128
 129         return 0;
 130 }
 131
 132 static int pmbus_probe(struct i2c_client *client,
 133                        const struct i2c_device_id *id)
 134 {
 135         struct pmbus_driver_info *info;
 136         int ret;
 137
 138         info = kzalloc(sizeof(struct pmbus_driver_info), GFP_KERNEL);
 139         if (!info)
 140                 return -ENOMEM;
 141
 142         info->pages = id->driver_data;
 143         info->identify = pmbus_identify;
 144
 145         ret = pmbus_do_probe(client, id, info);
 146         if (ret < 0)
 147                 goto out;
 148         return 0;
 149
 150 out:
 151         kfree(info);
 152         return ret;
 153 }
 154
 155 static int pmbus_remove(struct i2c_client *client)
 156 {
 157         int ret;
 158         const struct pmbus_driver_info *info;
 159
 160         info = pmbus_get_driver_info(client);
 161         ret = pmbus_do_remove(client);
 162         kfree(info);
 163         return ret;
 164 }
 165
 166 /*
 167  * Use driver_data to set the number of pages supported by the chip.
 168  */
 169 static const struct i2c_device_id pmbus_id[] = {
 170         {"bmr450", 1},
 171         {"bmr451", 1},
 172         {"bmr453", 1},
 173         {"bmr454", 1},
 174         {"ltc2978", 8},
 175         {"pmbus", 0},
 176         {}
 177 };
 178
 179 MODULE_DEVICE_TABLE(i2c, pmbus_id);
 180
 181 /* This is the driver that will be inserted */
 182 static struct i2c_driver pmbus_driver = {
 183         .driver = {
 184                    .name = "pmbus",
 185                    },
 186         .probe = pmbus_probe,
 187         .remove = pmbus_remove,
 188         .id_table = pmbus_id,
 189 };
 190
 191 static int __init pmbus_init(void)
 192 {
 193         return i2c_add_driver(&pmbus_driver);
 194 }
 195
 196 static void __exit pmbus_exit(void)
 197 {
 198         i2c_del_driver(&pmbus_driver);
 199 }
 200
 201 MODULE_AUTHOR("Guenter Roeck");
 202 MODULE_DESCRIPTION("Generic PMBus driver");
 203 MODULE_LICENSE("GPL");
 204 module_init(pmbus_init);
 205 module_exit(pmbus_exit);