drivers/hwmon/pmbus/zl6100.c

   1 /*
   2  * Hardware monitoring driver for ZL6100 and compatibles
   3  *
   4  * Copyright (c) 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/i2c.h>
  27 #include <linux/ktime.h>
  28 #include <linux/delay.h>
  29 #include "pmbus.h"
  30
  31 enum chips { zl2004, zl2006, zl2008, zl2105, zl2106, zl6100, zl6105 };
  32
  33 struct zl6100_data {
  34         int id;
  35         ktime_t access;         /* chip access time */
  36         struct pmbus_driver_info info;
  37 };
  38
  39 #define to_zl6100_data(x)  container_of(x, struct zl6100_data, info)
  40
  41 #define ZL6100_DEVICE_ID                0xe4
  42
  43 #define ZL6100_WAIT_TIME                1000    /* uS   */
  44
  45 static ushort delay = ZL6100_WAIT_TIME;
  46 module_param(delay, ushort, 0644);
  47 MODULE_PARM_DESC(delay, "Delay between chip accesses in uS");
  48
  49 /* Some chips need a delay between accesses */
  50 static inline void zl6100_wait(const struct zl6100_data *data)
  51 {
  52         if (delay) {
  53                 s64 delta = ktime_us_delta(ktime_get(), data->access);
  54                 if (delta < delay)
  55                         udelay(delay - delta);
  56         }
  57 }
  58
  59 static int zl6100_read_word_data(struct i2c_client *client, int page, int reg)
  60 {
  61         const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
  62         struct zl6100_data *data = to_zl6100_data(info);
  63         int ret;
  64
  65         if (page || reg >= PMBUS_VIRT_BASE)
  66                 return -ENXIO;
  67
  68         zl6100_wait(data);
  69         ret = pmbus_read_word_data(client, page, reg);
  70         data->access = ktime_get();
  71
  72         return ret;
  73 }
  74
  75 static int zl6100_read_byte_data(struct i2c_client *client, int page, int reg)
  76 {
  77         const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
  78         struct zl6100_data *data = to_zl6100_data(info);
  79         int ret;
  80
  81         if (page > 0)
  82                 return -ENXIO;
  83
  84         zl6100_wait(data);
  85         ret = pmbus_read_byte_data(client, page, reg);
  86         data->access = ktime_get();
  87
  88         return ret;
  89 }
  90
  91 static int zl6100_write_word_data(struct i2c_client *client, int page, int reg,
  92                                   u16 word)
  93 {
  94         const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
  95         struct zl6100_data *data = to_zl6100_data(info);
  96         int ret;
  97
  98         if (page || reg >= PMBUS_VIRT_BASE)
  99                 return -ENXIO;
 100
 101         zl6100_wait(data);
 102         ret = pmbus_write_word_data(client, page, reg, word);
 103         data->access = ktime_get();
 104
 105         return ret;
 106 }
 107
 108 static int zl6100_write_byte(struct i2c_client *client, int page, u8 value)
 109 {
 110         const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
 111         struct zl6100_data *data = to_zl6100_data(info);
 112         int ret;
 113
 114         if (page > 0)
 115                 return -ENXIO;
 116
 117         zl6100_wait(data);
 118         ret = pmbus_write_byte(client, page, value);
 119         data->access = ktime_get();
 120
 121         return ret;
 122 }
 123
 124 static const struct i2c_device_id zl6100_id[] = {
 125         {"zl2004", zl2004},
 126         {"zl2006", zl2006},
 127         {"zl2008", zl2008},
 128         {"zl2105", zl2105},
 129         {"zl2106", zl2106},
 130         {"zl6100", zl6100},
 131         {"zl6105", zl6105},
 132         { }
 133 };
 134 MODULE_DEVICE_TABLE(i2c, zl6100_id);
 135
 136 static int zl6100_probe(struct i2c_client *client,
 137                         const struct i2c_device_id *id)
 138 {
 139         int ret;
 140         struct zl6100_data *data;
 141         struct pmbus_driver_info *info;
 142         u8 device_id[I2C_SMBUS_BLOCK_MAX + 1];
 143         const struct i2c_device_id *mid;
 144
 145         if (!i2c_check_functionality(client->adapter,
 146                                      I2C_FUNC_SMBUS_READ_BYTE_DATA
 147                                      | I2C_FUNC_SMBUS_READ_BLOCK_DATA))
 148                 return -ENODEV;
 149
 150         ret = i2c_smbus_read_block_data(client, ZL6100_DEVICE_ID,
 151                                         device_id);
 152         if (ret < 0) {
 153                 dev_err(&client->dev, "Failed to read device ID\n");
 154                 return ret;
 155         }
 156         device_id[ret] = '\0';
 157         dev_info(&client->dev, "Device ID %s\n", device_id);
 158
 159         mid = NULL;
 160         for (mid = zl6100_id; mid->name[0]; mid++) {
 161                 if (!strncasecmp(mid->name, device_id, strlen(mid->name)))
 162                         break;
 163         }
 164         if (!mid->name[0]) {
 165                 dev_err(&client->dev, "Unsupported device\n");
 166                 return -ENODEV;
 167         }
 168         if (id->driver_data != mid->driver_data)
 169                 dev_notice(&client->dev,
 170                            "Device mismatch: Configured %s, detected %s\n",
 171                            id->name, mid->name);
 172
 173         data = kzalloc(sizeof(struct zl6100_data), GFP_KERNEL);
 174         if (!data)
 175                 return -ENOMEM;
 176
 177         data->id = mid->driver_data;
 178
 179         /*
 180          * ZL2008, ZL2105, and ZL6100 are known to require a wait time
 181          * between I2C accesses. ZL2004 and ZL6105 are known to be safe.
 182          *
 183          * Only clear the wait time for chips known to be safe. The wait time
 184          * can be cleared later for additional chips if tests show that it
 185          * is not needed (in other words, better be safe than sorry).
 186          */
 187         if (data->id == zl2004 || data->id == zl6105)
 188                 delay = 0;
 189
 190         /*
 191          * Since there was a direct I2C device access above, wait before
 192          * accessing the chip again.
 193          * Set the timestamp, wait, then set it again. This should provide
 194          * enough buffer time to be safe.
 195          */
 196         data->access = ktime_get();
 197         zl6100_wait(data);
 198         data->access = ktime_get();
 199
 200         info = &data->info;
 201
 202         info->pages = 1;
 203         info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
 204           | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
 205           | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
 206           | PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP;
 207
 208         info->read_word_data = zl6100_read_word_data;
 209         info->read_byte_data = zl6100_read_byte_data;
 210         info->write_word_data = zl6100_write_word_data;
 211         info->write_byte = zl6100_write_byte;
 212
 213         ret = pmbus_do_probe(client, mid, info);
 214         if (ret)
 215                 goto err_mem;
 216         return 0;
 217
 218 err_mem:
 219         kfree(data);
 220         return ret;
 221 }
 222
 223 static int zl6100_remove(struct i2c_client *client)
 224 {
 225         const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
 226         const struct zl6100_data *data = to_zl6100_data(info);
 227
 228         pmbus_do_remove(client);
 229         kfree(data);
 230         return 0;
 231 }
 232
 233 static struct i2c_driver zl6100_driver = {
 234         .driver = {
 235                    .name = "zl6100",
 236                    },
 237         .probe = zl6100_probe,
 238         .remove = zl6100_remove,
 239         .id_table = zl6100_id,
 240 };
 241
 242 static int __init zl6100_init(void)
 243 {
 244         return i2c_add_driver(&zl6100_driver);
 245 }
 246
 247 static void __exit zl6100_exit(void)
 248 {
 249         i2c_del_driver(&zl6100_driver);
 250 }
 251
 252 MODULE_AUTHOR("Guenter Roeck");
 253 MODULE_DESCRIPTION("PMBus driver for ZL6100 and compatibles");
 254 MODULE_LICENSE("GPL");
 255 module_init(zl6100_init);
 256 module_exit(zl6100_exit);