1/*
2 * LM73 Sensor driver
3 * Based on LM75
4 *
5 * Copyright (C) 2007, CenoSYS (www.cenosys.com).
6 * Copyright (C) 2009, Bollore telecom (www.bolloretelecom.eu).
7 *
8 * Guillaume Ligneul <guillaume.ligneul@gmail.com>
9 * Adrien Demarez <adrien.demarez@bolloretelecom.eu>
10 * Jeremy Laine <jeremy.laine@bolloretelecom.eu>
11 * Chris Verges <kg4ysn@gmail.com>
12 *
13 * This software program is licensed subject to the GNU General Public License
14 * (GPL).Version 2,June 1991, available at
15 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
16 */
17
18#include <linux/module.h>
19#include <linux/init.h>
20#include <linux/i2c.h>
21#include <linux/hwmon.h>
22#include <linux/hwmon-sysfs.h>
23#include <linux/err.h>
24
25
26/* Addresses scanned */
27static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4c,
28					0x4d, 0x4e, I2C_CLIENT_END };
29
30/* LM73 registers */
31#define LM73_REG_INPUT		0x00
32#define LM73_REG_CONF		0x01
33#define LM73_REG_MAX		0x02
34#define LM73_REG_MIN		0x03
35#define LM73_REG_CTRL		0x04
36#define LM73_REG_ID		0x07
37
38#define LM73_ID			0x9001	/* 0x0190, byte-swapped */
39#define DRVNAME			"lm73"
40#define LM73_TEMP_MIN		(-256000 / 250)
41#define LM73_TEMP_MAX		(255750 / 250)
42
43#define LM73_CTRL_RES_SHIFT	5
44#define LM73_CTRL_RES_MASK	(BIT(5) | BIT(6))
45#define LM73_CTRL_TO_MASK	BIT(7)
46
47#define LM73_CTRL_HI_SHIFT	2
48#define LM73_CTRL_LO_SHIFT	1
49
50static const unsigned short lm73_convrates[] = {
51	14,	/* 11-bits (0.25000 C/LSB): RES1 Bit = 0, RES0 Bit = 0 */
52	28,	/* 12-bits (0.12500 C/LSB): RES1 Bit = 0, RES0 Bit = 1 */
53	56,	/* 13-bits (0.06250 C/LSB): RES1 Bit = 1, RES0 Bit = 0 */
54	112,	/* 14-bits (0.03125 C/LSB): RES1 Bit = 1, RES0 Bit = 1 */
55};
56
57struct lm73_data {
58	struct i2c_client *client;
59	struct mutex lock;
60	u8 ctrl;			/* control register value */
61};
62
63/*-----------------------------------------------------------------------*/
64
65static ssize_t set_temp(struct device *dev, struct device_attribute *da,
66			const char *buf, size_t count)
67{
68	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
69	struct lm73_data *data = dev_get_drvdata(dev);
70	long temp;
71	short value;
72	s32 err;
73
74	int status = kstrtol(buf, 10, &temp);
75	if (status < 0)
76		return status;
77
78	/* Write value */
79	value = clamp_val(temp / 250, LM73_TEMP_MIN, LM73_TEMP_MAX) << 5;
80	err = i2c_smbus_write_word_swapped(data->client, attr->index, value);
81	return (err < 0) ? err : count;
82}
83
84static ssize_t show_temp(struct device *dev, struct device_attribute *da,
85			 char *buf)
86{
87	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
88	struct lm73_data *data = dev_get_drvdata(dev);
89	int temp;
90
91	s32 err = i2c_smbus_read_word_swapped(data->client, attr->index);
92	if (err < 0)
93		return err;
94
95	/* use integer division instead of equivalent right shift to
96	   guarantee arithmetic shift and preserve the sign */
97	temp = (((s16) err) * 250) / 32;
98	return scnprintf(buf, PAGE_SIZE, "%d\n", temp);
99}
100
101static ssize_t set_convrate(struct device *dev, struct device_attribute *da,
102			    const char *buf, size_t count)
103{
104	struct lm73_data *data = dev_get_drvdata(dev);
105	unsigned long convrate;
106	s32 err;
107	int res = 0;
108
109	err = kstrtoul(buf, 10, &convrate);
110	if (err < 0)
111		return err;
112
113	/*
114	 * Convert the desired conversion rate into register bits.
115	 * res is already initialized, and everything past the second-to-last
116	 * value in the array is treated as belonging to the last value
117	 * in the array.
118	 */
119	while (res < (ARRAY_SIZE(lm73_convrates) - 1) &&
120			convrate > lm73_convrates[res])
121		res++;
122
123	mutex_lock(&data->lock);
124	data->ctrl &= LM73_CTRL_TO_MASK;
125	data->ctrl |= res << LM73_CTRL_RES_SHIFT;
126	err = i2c_smbus_write_byte_data(data->client, LM73_REG_CTRL,
127					data->ctrl);
128	mutex_unlock(&data->lock);
129
130	if (err < 0)
131		return err;
132
133	return count;
134}
135
136static ssize_t show_convrate(struct device *dev, struct device_attribute *da,
137			     char *buf)
138{
139	struct lm73_data *data = dev_get_drvdata(dev);
140	int res;
141
142	res = (data->ctrl & LM73_CTRL_RES_MASK) >> LM73_CTRL_RES_SHIFT;
143	return scnprintf(buf, PAGE_SIZE, "%hu\n", lm73_convrates[res]);
144}
145
146static ssize_t show_maxmin_alarm(struct device *dev,
147				 struct device_attribute *da, char *buf)
148{
149	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
150	struct lm73_data *data = dev_get_drvdata(dev);
151	s32 ctrl;
152
153	mutex_lock(&data->lock);
154	ctrl = i2c_smbus_read_byte_data(data->client, LM73_REG_CTRL);
155	if (ctrl < 0)
156		goto abort;
157	data->ctrl = ctrl;
158	mutex_unlock(&data->lock);
159
160	return scnprintf(buf, PAGE_SIZE, "%d\n", (ctrl >> attr->index) & 1);
161
162abort:
163	mutex_unlock(&data->lock);
164	return ctrl;
165}
166
167/*-----------------------------------------------------------------------*/
168
169/* sysfs attributes for hwmon */
170
171static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
172			show_temp, set_temp, LM73_REG_MAX);
173static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
174			show_temp, set_temp, LM73_REG_MIN);
175static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
176			show_temp, NULL, LM73_REG_INPUT);
177static SENSOR_DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO,
178			show_convrate, set_convrate, 0);
179static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO,
180			show_maxmin_alarm, NULL, LM73_CTRL_HI_SHIFT);
181static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO,
182			show_maxmin_alarm, NULL, LM73_CTRL_LO_SHIFT);
183
184static struct attribute *lm73_attrs[] = {
185	&sensor_dev_attr_temp1_input.dev_attr.attr,
186	&sensor_dev_attr_temp1_max.dev_attr.attr,
187	&sensor_dev_attr_temp1_min.dev_attr.attr,
188	&sensor_dev_attr_update_interval.dev_attr.attr,
189	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
190	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
191	NULL
192};
193ATTRIBUTE_GROUPS(lm73);
194
195/*-----------------------------------------------------------------------*/
196
197/* device probe and removal */
198
199static int
200lm73_probe(struct i2c_client *client, const struct i2c_device_id *id)
201{
202	struct device *dev = &client->dev;
203	struct device *hwmon_dev;
204	struct lm73_data *data;
205	int ctrl;
206
207	data = devm_kzalloc(dev, sizeof(struct lm73_data), GFP_KERNEL);
208	if (!data)
209		return -ENOMEM;
210
211	data->client = client;
212	mutex_init(&data->lock);
213
214	ctrl = i2c_smbus_read_byte_data(client, LM73_REG_CTRL);
215	if (ctrl < 0)
216		return ctrl;
217	data->ctrl = ctrl;
218
219	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
220							   data, lm73_groups);
221	if (IS_ERR(hwmon_dev))
222		return PTR_ERR(hwmon_dev);
223
224	dev_info(dev, "sensor '%s'\n", client->name);
225
226	return 0;
227}
228
229static const struct i2c_device_id lm73_ids[] = {
230	{ "lm73", 0 },
231	{ /* LIST END */ }
232};
233MODULE_DEVICE_TABLE(i2c, lm73_ids);
234
235/* Return 0 if detection is successful, -ENODEV otherwise */
236static int lm73_detect(struct i2c_client *new_client,
237			struct i2c_board_info *info)
238{
239	struct i2c_adapter *adapter = new_client->adapter;
240	int id, ctrl, conf;
241
242	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
243					I2C_FUNC_SMBUS_WORD_DATA))
244		return -ENODEV;
245
246	/*
247	 * Do as much detection as possible with byte reads first, as word
248	 * reads can confuse other devices.
249	 */
250	ctrl = i2c_smbus_read_byte_data(new_client, LM73_REG_CTRL);
251	if (ctrl < 0 || (ctrl & 0x10))
252		return -ENODEV;
253
254	conf = i2c_smbus_read_byte_data(new_client, LM73_REG_CONF);
255	if (conf < 0 || (conf & 0x0c))
256		return -ENODEV;
257
258	id = i2c_smbus_read_byte_data(new_client, LM73_REG_ID);
259	if (id < 0 || id != (LM73_ID & 0xff))
260		return -ENODEV;
261
262	/* Check device ID */
263	id = i2c_smbus_read_word_data(new_client, LM73_REG_ID);
264	if (id < 0 || id != LM73_ID)
265		return -ENODEV;
266
267	strlcpy(info->type, "lm73", I2C_NAME_SIZE);
268
269	return 0;
270}
271
272static struct i2c_driver lm73_driver = {
273	.class		= I2C_CLASS_HWMON,
274	.driver = {
275		.name	= "lm73",
276	},
277	.probe		= lm73_probe,
278	.id_table	= lm73_ids,
279	.detect		= lm73_detect,
280	.address_list	= normal_i2c,
281};
282
283module_i2c_driver(lm73_driver);
284
285MODULE_AUTHOR("Guillaume Ligneul <guillaume.ligneul@gmail.com>");
286MODULE_DESCRIPTION("LM73 driver");
287MODULE_LICENSE("GPL");
288