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pmbus.c
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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 */
40  info->func[0] |= PMBUS_HAVE_VIN;
42  info->func[0] |= PMBUS_HAVE_VCAP;
44  info->func[0] |= PMBUS_HAVE_IIN;
46  info->func[0] |= PMBUS_HAVE_PIN;
47  if (info->func[0]
49  info->func[0] |= PMBUS_HAVE_STATUS_INPUT;
52  info->func[0] |= PMBUS_HAVE_FAN12;
54  info->func[0] |= PMBUS_HAVE_STATUS_FAN12;
55  }
58  info->func[0] |= PMBUS_HAVE_FAN34;
60  info->func[0] |= PMBUS_HAVE_STATUS_FAN34;
61  }
63  info->func[0] |= PMBUS_HAVE_TEMP;
65  info->func[0] |= PMBUS_HAVE_TEMP2;
67  info->func[0] |= PMBUS_HAVE_TEMP3;
68  if (info->func[0] & (PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2
70  && pmbus_check_byte_register(client, 0,
72  info->func[0] |= PMBUS_HAVE_STATUS_TEMP;
73 
74  /* Sensors detected on all pages */
75  for (page = 0; page < info->pages; page++) {
76  if (pmbus_check_word_register(client, page, PMBUS_READ_VOUT)) {
77  info->func[page] |= PMBUS_HAVE_VOUT;
78  if (pmbus_check_byte_register(client, page,
81  }
82  if (pmbus_check_word_register(client, page, PMBUS_READ_IOUT)) {
83  info->func[page] |= PMBUS_HAVE_IOUT;
84  if (pmbus_check_byte_register(client, 0,
87  }
88  if (pmbus_check_word_register(client, page, PMBUS_READ_POUT))
89  info->func[page] |= PMBUS_HAVE_POUT;
90  }
91 }
92 
93 /*
94  * Identify chip parameters.
95  */
96 static int pmbus_identify(struct i2c_client *client,
97  struct pmbus_driver_info *info)
98 {
99  int ret = 0;
100 
101  if (!info->pages) {
102  /*
103  * Check if the PAGE command is supported. If it is,
104  * keep setting the page number until it fails or until the
105  * maximum number of pages has been reached. Assume that
106  * this is the number of pages supported by the chip.
107  */
108  if (pmbus_check_byte_register(client, 0, PMBUS_PAGE)) {
109  int page;
110 
111  for (page = 1; page < PMBUS_PAGES; page++) {
112  if (pmbus_set_page(client, page) < 0)
113  break;
114  }
115  pmbus_set_page(client, 0);
116  info->pages = page;
117  } else {
118  info->pages = 1;
119  }
120  }
121 
122  if (pmbus_check_byte_register(client, 0, PMBUS_VOUT_MODE)) {
123  int vout_mode;
124 
125  vout_mode = pmbus_read_byte_data(client, 0, PMBUS_VOUT_MODE);
126  if (vout_mode >= 0 && vout_mode != 0xff) {
127  switch (vout_mode >> 5) {
128  case 0:
129  break;
130  case 1:
131  info->format[PSC_VOLTAGE_OUT] = vid;
132  break;
133  case 2:
134  info->format[PSC_VOLTAGE_OUT] = direct;
135  break;
136  default:
137  ret = -ENODEV;
138  goto abort;
139  }
140  }
141  }
142 
143  /*
144  * We should check if the COEFFICIENTS register is supported.
145  * If it is, and the chip is configured for direct mode, we can read
146  * the coefficients from the chip, one set per group of sensor
147  * registers.
148  *
149  * To do this, we will need access to a chip which actually supports the
150  * COEFFICIENTS command, since the command is too complex to implement
151  * without testing it. Until then, abort if a chip configured for direct
152  * mode was detected.
153  */
154  if (info->format[PSC_VOLTAGE_OUT] == direct) {
155  ret = -ENODEV;
156  goto abort;
157  }
158 
159  /* Try to find sensor groups */
160  pmbus_find_sensor_groups(client, info);
161 abort:
162  return ret;
163 }
164 
165 static int pmbus_probe(struct i2c_client *client,
166  const struct i2c_device_id *id)
167 {
168  struct pmbus_driver_info *info;
169 
170  info = devm_kzalloc(&client->dev, sizeof(struct pmbus_driver_info),
171  GFP_KERNEL);
172  if (!info)
173  return -ENOMEM;
174 
175  info->pages = id->driver_data;
176  info->identify = pmbus_identify;
177 
178  return pmbus_do_probe(client, id, info);
179 }
180 
181 /*
182  * Use driver_data to set the number of pages supported by the chip.
183  */
184 static const struct i2c_device_id pmbus_id[] = {
185  {"adp4000", 1},
186  {"bmr453", 1},
187  {"bmr454", 1},
188  {"mdt040", 1},
189  {"ncp4200", 1},
190  {"ncp4208", 1},
191  {"pdt003", 1},
192  {"pdt006", 1},
193  {"pdt012", 1},
194  {"pmbus", 0},
195  {"tps40400", 1},
196  {"tps40422", 2},
197  {"udt020", 1},
198  {}
199 };
200 
201 MODULE_DEVICE_TABLE(i2c, pmbus_id);
202 
203 /* This is the driver that will be inserted */
204 static struct i2c_driver pmbus_driver = {
205  .driver = {
206  .name = "pmbus",
207  },
208  .probe = pmbus_probe,
209  .remove = pmbus_do_remove,
210  .id_table = pmbus_id,
211 };
212 
213 module_i2c_driver(pmbus_driver);
214 
215 MODULE_AUTHOR("Guenter Roeck");
216 MODULE_DESCRIPTION("Generic PMBus driver");
217 MODULE_LICENSE("GPL");