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ucd9200.c
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1 /*
2  * Hardware monitoring driver for ucd9200 series Digital PWM System Controllers
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/i2c/pmbus.h>
28 #include "pmbus.h"
29 
30 #define UCD9200_PHASE_INFO 0xd2
31 #define UCD9200_DEVICE_ID 0xfd
32 
35 
36 static const struct i2c_device_id ucd9200_id[] = {
37  {"ucd9200", ucd9200},
38  {"ucd9220", ucd9220},
39  {"ucd9222", ucd9222},
40  {"ucd9224", ucd9224},
41  {"ucd9240", ucd9240},
42  {"ucd9244", ucd9244},
43  {"ucd9246", ucd9246},
44  {"ucd9248", ucd9248},
45  {}
46 };
47 MODULE_DEVICE_TABLE(i2c, ucd9200_id);
48 
49 static int ucd9200_probe(struct i2c_client *client,
50  const struct i2c_device_id *id)
51 {
52  u8 block_buffer[I2C_SMBUS_BLOCK_MAX + 1];
53  struct pmbus_driver_info *info;
54  const struct i2c_device_id *mid;
55  int i, j, ret;
56 
57  if (!i2c_check_functionality(client->adapter,
60  return -ENODEV;
61 
63  block_buffer);
64  if (ret < 0) {
65  dev_err(&client->dev, "Failed to read device ID\n");
66  return ret;
67  }
68  block_buffer[ret] = '\0';
69  dev_info(&client->dev, "Device ID %s\n", block_buffer);
70 
71  for (mid = ucd9200_id; mid->name[0]; mid++) {
72  if (!strncasecmp(mid->name, block_buffer, strlen(mid->name)))
73  break;
74  }
75  if (!mid->name[0]) {
76  dev_err(&client->dev, "Unsupported device\n");
77  return -ENODEV;
78  }
79  if (id->driver_data != ucd9200 && id->driver_data != mid->driver_data)
80  dev_notice(&client->dev,
81  "Device mismatch: Configured %s, detected %s\n",
82  id->name, mid->name);
83 
84  info = devm_kzalloc(&client->dev, sizeof(struct pmbus_driver_info),
85  GFP_KERNEL);
86  if (!info)
87  return -ENOMEM;
88 
90  block_buffer);
91  if (ret < 0) {
92  dev_err(&client->dev, "Failed to read phase information\n");
93  return ret;
94  }
95 
96  /*
97  * Calculate number of configured pages (rails) from PHASE_INFO
98  * register.
99  * Rails have to be sequential, so we can abort after finding
100  * the first unconfigured rail.
101  */
102  info->pages = 0;
103  for (i = 0; i < ret; i++) {
104  if (!block_buffer[i])
105  break;
106  info->pages++;
107  }
108  if (!info->pages) {
109  dev_err(&client->dev, "No rails configured\n");
110  return -ENODEV;
111  }
112  dev_info(&client->dev, "%d rails configured\n", info->pages);
113 
114  /*
115  * Set PHASE registers on all pages to 0xff to ensure that phase
116  * specific commands will apply to all phases of a given page (rail).
117  * This only affects the READ_IOUT and READ_TEMPERATURE2 registers.
118  * READ_IOUT will return the sum of currents of all phases of a rail,
119  * and READ_TEMPERATURE2 will return the maximum temperature detected
120  * for the the phases of the rail.
121  */
122  for (i = 0; i < info->pages; i++) {
123  /*
124  * Setting PAGE & PHASE fails once in a while for no obvious
125  * reason, so we need to retry a couple of times.
126  */
127  for (j = 0; j < 3; j++) {
128  ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, i);
129  if (ret < 0)
130  continue;
132  0xff);
133  if (ret < 0)
134  continue;
135  break;
136  }
137  if (ret < 0) {
138  dev_err(&client->dev,
139  "Failed to initialize PHASE registers\n");
140  return ret;
141  }
142  }
143  if (info->pages > 1)
145 
152 
153  for (i = 1; i < info->pages; i++)
158 
159  /* ucd9240 supports a single fan */
160  if (mid->driver_data == ucd9240)
162 
163  return pmbus_do_probe(client, mid, info);
164 }
165 
166 /* This is the driver that will be inserted */
167 static struct i2c_driver ucd9200_driver = {
168  .driver = {
169  .name = "ucd9200",
170  },
171  .probe = ucd9200_probe,
172  .remove = pmbus_do_remove,
173  .id_table = ucd9200_id,
174 };
175 
176 module_i2c_driver(ucd9200_driver);
177 
178 MODULE_AUTHOR("Guenter Roeck");
179 MODULE_DESCRIPTION("PMBus driver for TI UCD922x, UCD924x");
180 MODULE_LICENSE("GPL");