drivers/hwmon/pmbus/max15301.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Hardware monitoring driver for Maxim MAX15301
   4  *
   5  * Copyright (c) 2021 Flextronics International Sweden AB
   6  *
   7  * Even though the specification does not specifically mention it,
   8  * extensive empirical testing has revealed that auto-detection of
   9  * limit-registers will fail in a random fashion unless the delay
  10  * parameter is set to above about 80us. The default delay is set
  11  * to 100us to include some safety margin.
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17 #include <linux/err.h>
  18 #include <linux/slab.h>
  19 #include <linux/i2c.h>
  20 #include <linux/ktime.h>
  21 #include <linux/delay.h>
  22 #include <linux/pmbus.h>
  23 #include "pmbus.h"
  24
  25 static const struct i2c_device_id max15301_id[] = {
  26         { "bmr461" },
  27         { "max15301" },
  28         {}
  29 };
  30 MODULE_DEVICE_TABLE(i2c, max15301_id);
  31
  32 struct max15301_data {
  33         int id;
  34         struct pmbus_driver_info info;
  35 };
  36
  37 #define to_max15301_data(x)  container_of(x, struct max15301_data, info)
  38
  39 #define MAX15301_WAIT_TIME              100     /* us   */
  40
  41 static ushort delay = MAX15301_WAIT_TIME;
  42 module_param(delay, ushort, 0644);
  43 MODULE_PARM_DESC(delay, "Delay between chip accesses in us");
  44
  45 static struct max15301_data max15301_data = {
  46         .info = {
  47                 .pages = 1,
  48                 .func[0] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
  49                         | PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
  50                         | PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2
  51                         | PMBUS_HAVE_STATUS_TEMP
  52                         | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT,
  53         }
  54 };
  55
  56 static int max15301_probe(struct i2c_client *client)
  57 {
  58         int status;
  59         u8 device_id[I2C_SMBUS_BLOCK_MAX + 1];
  60         const struct i2c_device_id *mid;
  61         struct pmbus_driver_info *info = &max15301_data.info;
  62
  63         if (!i2c_check_functionality(client->adapter,
  64                                      I2C_FUNC_SMBUS_READ_BYTE_DATA
  65                                      | I2C_FUNC_SMBUS_BLOCK_DATA))
  66                 return -ENODEV;
  67
  68         status = i2c_smbus_read_block_data(client, PMBUS_IC_DEVICE_ID, device_id);
  69         if (status < 0) {
  70                 dev_err(&client->dev, "Failed to read Device Id\n");
  71                 return status;
  72         }
  73         for (mid = max15301_id; mid->name[0]; mid++) {
  74                 if (!strncasecmp(mid->name, device_id, strlen(mid->name)))
  75                         break;
  76         }
  77         if (!mid->name[0]) {
  78                 dev_err(&client->dev, "Unsupported device\n");
  79                 return -ENODEV;
  80         }
  81
  82         info->access_delay = delay;
  83
  84         return pmbus_do_probe(client, info);
  85 }
  86
  87 static struct i2c_driver max15301_driver = {
  88         .driver = {
  89                    .name = "max15301",
  90                    },
  91         .probe = max15301_probe,
  92         .id_table = max15301_id,
  93 };
  94
  95 module_i2c_driver(max15301_driver);
  96
  97 MODULE_AUTHOR("Erik Rosen <erik.rosen@metormote.com>");
  98 MODULE_DESCRIPTION("PMBus driver for Maxim MAX15301");
  99 MODULE_LICENSE("GPL");
 100 MODULE_IMPORT_NS("PMBUS");