xref: /openbmc/linux/drivers/hwmon/ds620.c (revision be709d48)
1 /*
2  *  ds620.c - Support for temperature sensor and thermostat DS620
3  *
4  *  Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
5  *
6  *  based on ds1621.c by Christian W. Zuckschwerdt  <zany@triq.net>
7  *
8  *  This program is free software; you can redistribute it and/or modify
9  *  it under the terms of the GNU General Public License as published by
10  *  the Free Software Foundation; either version 2 of the License, or
11  *  (at your option) any later version.
12  *
13  *  This program is distributed in the hope that it will be useful,
14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  *  GNU General Public License for more details.
17  *
18  *  You should have received a copy of the GNU General Public License
19  *  along with this program; if not, write to the Free Software
20  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21  */
22 
23 #include <linux/module.h>
24 #include <linux/init.h>
25 #include <linux/slab.h>
26 #include <linux/jiffies.h>
27 #include <linux/i2c.h>
28 #include <linux/hwmon.h>
29 #include <linux/hwmon-sysfs.h>
30 #include <linux/err.h>
31 #include <linux/mutex.h>
32 #include <linux/sysfs.h>
33 #include <linux/platform_data/ds620.h>
34 
35 /*
36  * Many DS620 constants specified below
37  *  15   14   13   12   11   10   09    08
38  * |Done|NVB |THF |TLF |R1  |R0  |AUTOC|1SHOT|
39  *
40  *  07   06   05   04   03   02   01    00
41  * |PO2 |PO1 |A2  |A1  |A0  |    |     |     |
42  */
43 #define DS620_REG_CONFIG_DONE		0x8000
44 #define DS620_REG_CONFIG_NVB		0x4000
45 #define DS620_REG_CONFIG_THF		0x2000
46 #define DS620_REG_CONFIG_TLF		0x1000
47 #define DS620_REG_CONFIG_R1		0x0800
48 #define DS620_REG_CONFIG_R0		0x0400
49 #define DS620_REG_CONFIG_AUTOC		0x0200
50 #define DS620_REG_CONFIG_1SHOT		0x0100
51 #define DS620_REG_CONFIG_PO2		0x0080
52 #define DS620_REG_CONFIG_PO1		0x0040
53 #define DS620_REG_CONFIG_A2		0x0020
54 #define DS620_REG_CONFIG_A1		0x0010
55 #define DS620_REG_CONFIG_A0		0x0008
56 
57 /* The DS620 registers */
58 static const u8 DS620_REG_TEMP[3] = {
59 	0xAA,			/* input, word, RO */
60 	0xA2,			/* min, word, RW */
61 	0xA0,			/* max, word, RW */
62 };
63 
64 #define DS620_REG_CONF		0xAC	/* word, RW */
65 #define DS620_COM_START		0x51	/* no data */
66 #define DS620_COM_STOP		0x22	/* no data */
67 
68 /* Each client has this additional data */
69 struct ds620_data {
70 	struct i2c_client *client;
71 	struct mutex update_lock;
72 	char valid;		/* !=0 if following fields are valid */
73 	unsigned long last_updated;	/* In jiffies */
74 
75 	s16 temp[3];		/* Register values, word */
76 };
77 
78 static void ds620_init_client(struct i2c_client *client)
79 {
80 	struct ds620_platform_data *ds620_info = dev_get_platdata(&client->dev);
81 	u16 conf, new_conf;
82 
83 	new_conf = conf =
84 	    i2c_smbus_read_word_swapped(client, DS620_REG_CONF);
85 
86 	/* switch to continuous conversion mode */
87 	new_conf &= ~DS620_REG_CONFIG_1SHOT;
88 	/* already high at power-on, but don't trust the BIOS! */
89 	new_conf |= DS620_REG_CONFIG_PO2;
90 	/* thermostat mode according to platform data */
91 	if (ds620_info && ds620_info->pomode == 1)
92 		new_conf &= ~DS620_REG_CONFIG_PO1; /* PO_LOW */
93 	else if (ds620_info && ds620_info->pomode == 2)
94 		new_conf |= DS620_REG_CONFIG_PO1; /* PO_HIGH */
95 	else
96 		new_conf &= ~DS620_REG_CONFIG_PO2; /* always low */
97 	/* with highest precision */
98 	new_conf |= DS620_REG_CONFIG_R1 | DS620_REG_CONFIG_R0;
99 
100 	if (conf != new_conf)
101 		i2c_smbus_write_word_swapped(client, DS620_REG_CONF, new_conf);
102 
103 	/* start conversion */
104 	i2c_smbus_write_byte(client, DS620_COM_START);
105 }
106 
107 static struct ds620_data *ds620_update_client(struct device *dev)
108 {
109 	struct ds620_data *data = dev_get_drvdata(dev);
110 	struct i2c_client *client = data->client;
111 	struct ds620_data *ret = data;
112 
113 	mutex_lock(&data->update_lock);
114 
115 	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
116 	    || !data->valid) {
117 		int i;
118 		int res;
119 
120 		dev_dbg(&client->dev, "Starting ds620 update\n");
121 
122 		for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
123 			res = i2c_smbus_read_word_swapped(client,
124 							  DS620_REG_TEMP[i]);
125 			if (res < 0) {
126 				ret = ERR_PTR(res);
127 				goto abort;
128 			}
129 
130 			data->temp[i] = res;
131 		}
132 
133 		data->last_updated = jiffies;
134 		data->valid = 1;
135 	}
136 abort:
137 	mutex_unlock(&data->update_lock);
138 
139 	return ret;
140 }
141 
142 static ssize_t temp_show(struct device *dev, struct device_attribute *da,
143 			 char *buf)
144 {
145 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
146 	struct ds620_data *data = ds620_update_client(dev);
147 
148 	if (IS_ERR(data))
149 		return PTR_ERR(data);
150 
151 	return sprintf(buf, "%d\n", ((data->temp[attr->index] / 8) * 625) / 10);
152 }
153 
154 static ssize_t temp_store(struct device *dev, struct device_attribute *da,
155 			  const char *buf, size_t count)
156 {
157 	int res;
158 	long val;
159 
160 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
161 	struct ds620_data *data = dev_get_drvdata(dev);
162 	struct i2c_client *client = data->client;
163 
164 	res = kstrtol(buf, 10, &val);
165 
166 	if (res)
167 		return res;
168 
169 	val = (clamp_val(val, -128000, 128000) * 10 / 625) * 8;
170 
171 	mutex_lock(&data->update_lock);
172 	data->temp[attr->index] = val;
173 	i2c_smbus_write_word_swapped(client, DS620_REG_TEMP[attr->index],
174 				     data->temp[attr->index]);
175 	mutex_unlock(&data->update_lock);
176 	return count;
177 }
178 
179 static ssize_t alarm_show(struct device *dev, struct device_attribute *da,
180 			  char *buf)
181 {
182 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
183 	struct ds620_data *data = ds620_update_client(dev);
184 	struct i2c_client *client;
185 	u16 conf, new_conf;
186 	int res;
187 
188 	if (IS_ERR(data))
189 		return PTR_ERR(data);
190 
191 	client = data->client;
192 
193 	/* reset alarms if necessary */
194 	res = i2c_smbus_read_word_swapped(client, DS620_REG_CONF);
195 	if (res < 0)
196 		return res;
197 
198 	new_conf = conf = res;
199 	new_conf &= ~attr->index;
200 	if (conf != new_conf) {
201 		res = i2c_smbus_write_word_swapped(client, DS620_REG_CONF,
202 						   new_conf);
203 		if (res < 0)
204 			return res;
205 	}
206 
207 	return sprintf(buf, "%d\n", !!(conf & attr->index));
208 }
209 
210 static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, 0);
211 static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, 1);
212 static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, 2);
213 static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, DS620_REG_CONFIG_TLF);
214 static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, DS620_REG_CONFIG_THF);
215 
216 static struct attribute *ds620_attrs[] = {
217 	&sensor_dev_attr_temp1_input.dev_attr.attr,
218 	&sensor_dev_attr_temp1_min.dev_attr.attr,
219 	&sensor_dev_attr_temp1_max.dev_attr.attr,
220 	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
221 	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
222 	NULL
223 };
224 
225 ATTRIBUTE_GROUPS(ds620);
226 
227 static int ds620_probe(struct i2c_client *client,
228 		       const struct i2c_device_id *id)
229 {
230 	struct device *dev = &client->dev;
231 	struct device *hwmon_dev;
232 	struct ds620_data *data;
233 
234 	data = devm_kzalloc(dev, sizeof(struct ds620_data), GFP_KERNEL);
235 	if (!data)
236 		return -ENOMEM;
237 
238 	data->client = client;
239 	mutex_init(&data->update_lock);
240 
241 	/* Initialize the DS620 chip */
242 	ds620_init_client(client);
243 
244 	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
245 							   data, ds620_groups);
246 	return PTR_ERR_OR_ZERO(hwmon_dev);
247 }
248 
249 static const struct i2c_device_id ds620_id[] = {
250 	{"ds620", 0},
251 	{}
252 };
253 
254 MODULE_DEVICE_TABLE(i2c, ds620_id);
255 
256 /* This is the driver that will be inserted */
257 static struct i2c_driver ds620_driver = {
258 	.class = I2C_CLASS_HWMON,
259 	.driver = {
260 		   .name = "ds620",
261 	},
262 	.probe = ds620_probe,
263 	.id_table = ds620_id,
264 };
265 
266 module_i2c_driver(ds620_driver);
267 
268 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
269 MODULE_DESCRIPTION("DS620 driver");
270 MODULE_LICENSE("GPL");
271