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 */
33static 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_word_register(client, 0, PMBUS_READ_TEMPERATURE_2))
65		info->func[0] |= PMBUS_HAVE_TEMP2;
66	if (pmbus_check_word_register(client, 0, PMBUS_READ_TEMPERATURE_3))
67		info->func[0] |= PMBUS_HAVE_TEMP3;
68	if (info->func[0] & (PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2
69			     | PMBUS_HAVE_TEMP3)
70	    && pmbus_check_byte_register(client, 0,
71					 PMBUS_STATUS_TEMPERATURE))
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,
79						      PMBUS_STATUS_VOUT))
80				info->func[page] |= PMBUS_HAVE_STATUS_VOUT;
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,
85						      PMBUS_STATUS_IOUT))
86				info->func[page] |= PMBUS_HAVE_STATUS_IOUT;
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 */
96static 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);
161abort:
162	return ret;
163}
164
165static 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 */
184static 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	{"udt020", 1},
197	{}
198};
199
200MODULE_DEVICE_TABLE(i2c, pmbus_id);
201
202/* This is the driver that will be inserted */
203static struct i2c_driver pmbus_driver = {
204	.driver = {
205		   .name = "pmbus",
206		   },
207	.probe = pmbus_probe,
208	.remove = pmbus_do_remove,
209	.id_table = pmbus_id,
210};
211
212module_i2c_driver(pmbus_driver);
213
214MODULE_AUTHOR("Guenter Roeck");
215MODULE_DESCRIPTION("Generic PMBus driver");
216MODULE_LICENSE("GPL");
217