xref: /openbmc/linux/drivers/hwmon/ds1621.c (revision 22246614)
1 /*
2     ds1621.c - Part of lm_sensors, Linux kernel modules for hardware
3              monitoring
4     Christian W. Zuckschwerdt  <zany@triq.net>  2000-11-23
5     based on lm75.c by Frodo Looijaard <frodol@dds.nl>
6     Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
7     the help of Jean Delvare <khali@linux-fr.org>
8 
9     This program is free software; you can redistribute it and/or modify
10     it under the terms of the GNU General Public License as published by
11     the Free Software Foundation; either version 2 of the License, or
12     (at your option) any later version.
13 
14     This program is distributed in the hope that it will be useful,
15     but WITHOUT ANY WARRANTY; without even the implied warranty of
16     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17     GNU General Public License for more details.
18 
19     You should have received a copy of the GNU General Public License
20     along with this program; if not, write to the Free Software
21     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 */
23 
24 #include <linux/module.h>
25 #include <linux/init.h>
26 #include <linux/slab.h>
27 #include <linux/jiffies.h>
28 #include <linux/i2c.h>
29 #include <linux/hwmon.h>
30 #include <linux/hwmon-sysfs.h>
31 #include <linux/err.h>
32 #include <linux/mutex.h>
33 #include <linux/sysfs.h>
34 #include "lm75.h"
35 
36 /* Addresses to scan */
37 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
38 					0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
39 
40 /* Insmod parameters */
41 I2C_CLIENT_INSMOD_1(ds1621);
42 static int polarity = -1;
43 module_param(polarity, int, 0);
44 MODULE_PARM_DESC(polarity, "Output's polarity: 0 = active high, 1 = active low");
45 
46 /* Many DS1621 constants specified below */
47 /* Config register used for detection         */
48 /*  7    6    5    4    3    2    1    0      */
49 /* |Done|THF |TLF |NVB | X  | X  |POL |1SHOT| */
50 #define DS1621_REG_CONFIG_NVB		0x10
51 #define DS1621_REG_CONFIG_POLARITY	0x02
52 #define DS1621_REG_CONFIG_1SHOT		0x01
53 #define DS1621_REG_CONFIG_DONE		0x80
54 
55 /* The DS1621 registers */
56 static const u8 DS1621_REG_TEMP[3] = {
57 	0xAA,		/* input, word, RO */
58 	0xA2,		/* min, word, RW */
59 	0xA1,		/* max, word, RW */
60 };
61 #define DS1621_REG_CONF			0xAC /* byte, RW */
62 #define DS1621_COM_START		0xEE /* no data */
63 #define DS1621_COM_STOP			0x22 /* no data */
64 
65 /* The DS1621 configuration register */
66 #define DS1621_ALARM_TEMP_HIGH		0x40
67 #define DS1621_ALARM_TEMP_LOW		0x20
68 
69 /* Conversions */
70 #define ALARMS_FROM_REG(val) ((val) & \
71                               (DS1621_ALARM_TEMP_HIGH | DS1621_ALARM_TEMP_LOW))
72 
73 /* Each client has this additional data */
74 struct ds1621_data {
75 	struct i2c_client client;
76 	struct device *hwmon_dev;
77 	struct mutex update_lock;
78 	char valid;			/* !=0 if following fields are valid */
79 	unsigned long last_updated;	/* In jiffies */
80 
81 	u16 temp[3];			/* Register values, word */
82 	u8 conf;			/* Register encoding, combined */
83 };
84 
85 static int ds1621_attach_adapter(struct i2c_adapter *adapter);
86 static int ds1621_detect(struct i2c_adapter *adapter, int address,
87 			 int kind);
88 static void ds1621_init_client(struct i2c_client *client);
89 static int ds1621_detach_client(struct i2c_client *client);
90 static struct ds1621_data *ds1621_update_client(struct device *dev);
91 
92 /* This is the driver that will be inserted */
93 static struct i2c_driver ds1621_driver = {
94 	.driver = {
95 		.name	= "ds1621",
96 	},
97 	.attach_adapter	= ds1621_attach_adapter,
98 	.detach_client	= ds1621_detach_client,
99 };
100 
101 /* All registers are word-sized, except for the configuration register.
102    DS1621 uses a high-byte first convention, which is exactly opposite to
103    the SMBus standard. */
104 static int ds1621_read_value(struct i2c_client *client, u8 reg)
105 {
106 	if (reg == DS1621_REG_CONF)
107 		return i2c_smbus_read_byte_data(client, reg);
108 	else
109 		return swab16(i2c_smbus_read_word_data(client, reg));
110 }
111 
112 static int ds1621_write_value(struct i2c_client *client, u8 reg, u16 value)
113 {
114 	if (reg == DS1621_REG_CONF)
115 		return i2c_smbus_write_byte_data(client, reg, value);
116 	else
117 		return i2c_smbus_write_word_data(client, reg, swab16(value));
118 }
119 
120 static void ds1621_init_client(struct i2c_client *client)
121 {
122 	int reg = ds1621_read_value(client, DS1621_REG_CONF);
123 	/* switch to continuous conversion mode */
124 	reg &= ~ DS1621_REG_CONFIG_1SHOT;
125 
126 	/* setup output polarity */
127 	if (polarity == 0)
128 		reg &= ~DS1621_REG_CONFIG_POLARITY;
129 	else if (polarity == 1)
130 		reg |= DS1621_REG_CONFIG_POLARITY;
131 
132 	ds1621_write_value(client, DS1621_REG_CONF, reg);
133 
134 	/* start conversion */
135 	i2c_smbus_write_byte(client, DS1621_COM_START);
136 }
137 
138 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
139 			 char *buf)
140 {
141 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
142 	struct ds1621_data *data = ds1621_update_client(dev);
143 	return sprintf(buf, "%d\n",
144 		       LM75_TEMP_FROM_REG(data->temp[attr->index]));
145 }
146 
147 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
148 			const char *buf, size_t count)
149 {
150 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
151 	struct i2c_client *client = to_i2c_client(dev);
152 	struct ds1621_data *data = ds1621_update_client(dev);
153 	u16 val = LM75_TEMP_TO_REG(simple_strtol(buf, NULL, 10));
154 
155 	mutex_lock(&data->update_lock);
156 	data->temp[attr->index] = val;
157 	ds1621_write_value(client, DS1621_REG_TEMP[attr->index],
158 			   data->temp[attr->index]);
159 	mutex_unlock(&data->update_lock);
160 	return count;
161 }
162 
163 static ssize_t show_alarms(struct device *dev, struct device_attribute *da,
164 			   char *buf)
165 {
166 	struct ds1621_data *data = ds1621_update_client(dev);
167 	return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
168 }
169 
170 static ssize_t show_alarm(struct device *dev, struct device_attribute *da,
171 			  char *buf)
172 {
173 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
174 	struct ds1621_data *data = ds1621_update_client(dev);
175 	return sprintf(buf, "%d\n", !!(data->conf & attr->index));
176 }
177 
178 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
179 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
180 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, 1);
181 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 2);
182 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
183 		DS1621_ALARM_TEMP_LOW);
184 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
185 		DS1621_ALARM_TEMP_HIGH);
186 
187 static struct attribute *ds1621_attributes[] = {
188 	&sensor_dev_attr_temp1_input.dev_attr.attr,
189 	&sensor_dev_attr_temp1_min.dev_attr.attr,
190 	&sensor_dev_attr_temp1_max.dev_attr.attr,
191 	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
192 	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
193 	&dev_attr_alarms.attr,
194 	NULL
195 };
196 
197 static const struct attribute_group ds1621_group = {
198 	.attrs = ds1621_attributes,
199 };
200 
201 
202 static int ds1621_attach_adapter(struct i2c_adapter *adapter)
203 {
204 	if (!(adapter->class & I2C_CLASS_HWMON))
205 		return 0;
206 	return i2c_probe(adapter, &addr_data, ds1621_detect);
207 }
208 
209 /* This function is called by i2c_probe */
210 static int ds1621_detect(struct i2c_adapter *adapter, int address,
211 			 int kind)
212 {
213 	int conf, temp;
214 	struct i2c_client *client;
215 	struct ds1621_data *data;
216 	int i, err = 0;
217 
218 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
219 				     | I2C_FUNC_SMBUS_WORD_DATA
220 				     | I2C_FUNC_SMBUS_WRITE_BYTE))
221 		goto exit;
222 
223 	/* OK. For now, we presume we have a valid client. We now create the
224 	   client structure, even though we cannot fill it completely yet.
225 	   But it allows us to access ds1621_{read,write}_value. */
226 	if (!(data = kzalloc(sizeof(struct ds1621_data), GFP_KERNEL))) {
227 		err = -ENOMEM;
228 		goto exit;
229 	}
230 
231 	client = &data->client;
232 	i2c_set_clientdata(client, data);
233 	client->addr = address;
234 	client->adapter = adapter;
235 	client->driver = &ds1621_driver;
236 
237 	/* Now, we do the remaining detection. It is lousy. */
238 	if (kind < 0) {
239 		/* The NVB bit should be low if no EEPROM write has been
240 		   requested during the latest 10ms, which is highly
241 		   improbable in our case. */
242 		conf = ds1621_read_value(client, DS1621_REG_CONF);
243 		if (conf & DS1621_REG_CONFIG_NVB)
244 			goto exit_free;
245 		/* The 7 lowest bits of a temperature should always be 0. */
246 		for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
247 			temp = ds1621_read_value(client, DS1621_REG_TEMP[i]);
248 			if (temp & 0x007f)
249 				goto exit_free;
250 		}
251 	}
252 
253 	/* Fill in remaining client fields and put it into the global list */
254 	strlcpy(client->name, "ds1621", I2C_NAME_SIZE);
255 	mutex_init(&data->update_lock);
256 
257 	/* Tell the I2C layer a new client has arrived */
258 	if ((err = i2c_attach_client(client)))
259 		goto exit_free;
260 
261 	/* Initialize the DS1621 chip */
262 	ds1621_init_client(client);
263 
264 	/* Register sysfs hooks */
265 	if ((err = sysfs_create_group(&client->dev.kobj, &ds1621_group)))
266 		goto exit_detach;
267 
268 	data->hwmon_dev = hwmon_device_register(&client->dev);
269 	if (IS_ERR(data->hwmon_dev)) {
270 		err = PTR_ERR(data->hwmon_dev);
271 		goto exit_remove_files;
272 	}
273 
274 	return 0;
275 
276       exit_remove_files:
277 	sysfs_remove_group(&client->dev.kobj, &ds1621_group);
278       exit_detach:
279 	i2c_detach_client(client);
280       exit_free:
281 	kfree(data);
282       exit:
283 	return err;
284 }
285 
286 static int ds1621_detach_client(struct i2c_client *client)
287 {
288 	struct ds1621_data *data = i2c_get_clientdata(client);
289 	int err;
290 
291 	hwmon_device_unregister(data->hwmon_dev);
292 	sysfs_remove_group(&client->dev.kobj, &ds1621_group);
293 
294 	if ((err = i2c_detach_client(client)))
295 		return err;
296 
297 	kfree(data);
298 
299 	return 0;
300 }
301 
302 
303 static struct ds1621_data *ds1621_update_client(struct device *dev)
304 {
305 	struct i2c_client *client = to_i2c_client(dev);
306 	struct ds1621_data *data = i2c_get_clientdata(client);
307 	u8 new_conf;
308 
309 	mutex_lock(&data->update_lock);
310 
311 	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
312 	    || !data->valid) {
313 		int i;
314 
315 		dev_dbg(&client->dev, "Starting ds1621 update\n");
316 
317 		data->conf = ds1621_read_value(client, DS1621_REG_CONF);
318 
319 		for (i = 0; i < ARRAY_SIZE(data->temp); i++)
320 			data->temp[i] = ds1621_read_value(client,
321 							  DS1621_REG_TEMP[i]);
322 
323 		/* reset alarms if necessary */
324 		new_conf = data->conf;
325 		if (data->temp[0] > data->temp[1])	/* input > min */
326 			new_conf &= ~DS1621_ALARM_TEMP_LOW;
327 		if (data->temp[0] < data->temp[2])	/* input < max */
328 			new_conf &= ~DS1621_ALARM_TEMP_HIGH;
329 		if (data->conf != new_conf)
330 			ds1621_write_value(client, DS1621_REG_CONF,
331 					   new_conf);
332 
333 		data->last_updated = jiffies;
334 		data->valid = 1;
335 	}
336 
337 	mutex_unlock(&data->update_lock);
338 
339 	return data;
340 }
341 
342 static int __init ds1621_init(void)
343 {
344 	return i2c_add_driver(&ds1621_driver);
345 }
346 
347 static void __exit ds1621_exit(void)
348 {
349 	i2c_del_driver(&ds1621_driver);
350 }
351 
352 
353 MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
354 MODULE_DESCRIPTION("DS1621 driver");
355 MODULE_LICENSE("GPL");
356 
357 module_init(ds1621_init);
358 module_exit(ds1621_exit);
359