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
33enum chips { ucd9200, ucd9220, ucd9222, ucd9224, ucd9240, ucd9244, ucd9246,
34	     ucd9248 };
35
36static 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};
47MODULE_DEVICE_TABLE(i2c, ucd9200_id);
48
49static 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,
58				     I2C_FUNC_SMBUS_BYTE_DATA |
59				     I2C_FUNC_SMBUS_BLOCK_DATA))
60		return -ENODEV;
61
62	ret = i2c_smbus_read_block_data(client, UCD9200_DEVICE_ID,
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
89	ret = i2c_smbus_read_block_data(client, UCD9200_PHASE_INFO,
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;
131			ret = i2c_smbus_write_byte_data(client, PMBUS_PHASE,
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)
144		i2c_smbus_write_byte_data(client, PMBUS_PAGE, 0);
145
146	info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT |
147			PMBUS_HAVE_IIN | PMBUS_HAVE_PIN |
148			PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
149			PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
150			PMBUS_HAVE_POUT | PMBUS_HAVE_TEMP |
151			PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP;
152
153	for (i = 1; i < info->pages; i++)
154		info->func[i] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
155			PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
156			PMBUS_HAVE_POUT |
157			PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP;
158
159	/* ucd9240 supports a single fan */
160	if (mid->driver_data == ucd9240)
161		info->func[0] |= PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12;
162
163	return pmbus_do_probe(client, mid, info);
164}
165
166/* This is the driver that will be inserted */
167static 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
176module_i2c_driver(ucd9200_driver);
177
178MODULE_AUTHOR("Guenter Roeck");
179MODULE_DESCRIPTION("PMBus driver for TI UCD922x, UCD924x");
180MODULE_LICENSE("GPL");
181