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/i2c/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 */
58static 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 */
69struct 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
78static 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
107static 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	}
136abort:
137	mutex_unlock(&data->update_lock);
138
139	return ret;
140}
141
142static ssize_t show_temp(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
154static ssize_t set_temp(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 = (val * 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
179static ssize_t show_alarm(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
210static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
211static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, 1);
212static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 2);
213static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
214			  DS620_REG_CONFIG_TLF);
215static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
216			  DS620_REG_CONFIG_THF);
217
218static struct attribute *ds620_attrs[] = {
219	&sensor_dev_attr_temp1_input.dev_attr.attr,
220	&sensor_dev_attr_temp1_min.dev_attr.attr,
221	&sensor_dev_attr_temp1_max.dev_attr.attr,
222	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
223	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
224	NULL
225};
226
227ATTRIBUTE_GROUPS(ds620);
228
229static int ds620_probe(struct i2c_client *client,
230		       const struct i2c_device_id *id)
231{
232	struct device *dev = &client->dev;
233	struct device *hwmon_dev;
234	struct ds620_data *data;
235
236	data = devm_kzalloc(dev, sizeof(struct ds620_data), GFP_KERNEL);
237	if (!data)
238		return -ENOMEM;
239
240	data->client = client;
241	mutex_init(&data->update_lock);
242
243	/* Initialize the DS620 chip */
244	ds620_init_client(client);
245
246	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
247							   data, ds620_groups);
248	return PTR_ERR_OR_ZERO(hwmon_dev);
249}
250
251static const struct i2c_device_id ds620_id[] = {
252	{"ds620", 0},
253	{}
254};
255
256MODULE_DEVICE_TABLE(i2c, ds620_id);
257
258/* This is the driver that will be inserted */
259static struct i2c_driver ds620_driver = {
260	.class = I2C_CLASS_HWMON,
261	.driver = {
262		   .name = "ds620",
263	},
264	.probe = ds620_probe,
265	.id_table = ds620_id,
266};
267
268module_i2c_driver(ds620_driver);
269
270MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
271MODULE_DESCRIPTION("DS620 driver");
272MODULE_LICENSE("GPL");
273