1/*
2 * Driver for +/-1 degree C, SMBus-Compatible Remote/Local Temperature Sensor
3 * with Overtemperature Alarm
4 *
5 * Copyright (C) 2011 AppearTV AS
6 *
7 * Derived from:
8 *
9 * Based on the max1619 driver.
10 * Copyright (C) 2003-2004 Oleksij Rempel <bug-track@fisher-privat.net>
11 * Jean Delvare <jdelvare@suse.de>
12 *
13 * The MAX6642 is a sensor chip made by Maxim.
14 * It reports up to two temperatures (its own plus up to
15 * one external one). Complete datasheet can be
16 * obtained from Maxim's website at:
17 * http://datasheets.maxim-ic.com/en/ds/MAX6642.pdf
18 *
19 * This program is free software; you can redistribute it and/or modify
20 * it under the terms of the GNU General Public License as published by
21 * the Free Software Foundation; either version 2 of the License, or
22 * (at your option) any later version.
23 *
24 * This program is distributed in the hope that it will be useful,
25 * but WITHOUT ANY WARRANTY; without even the implied warranty of
26 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
27 * GNU General Public License for more details.
28 *
29 * You should have received a copy of the GNU General Public License
30 * along with this program; if not, write to the Free Software
31 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
32 */
33
34
35#include <linux/module.h>
36#include <linux/init.h>
37#include <linux/slab.h>
38#include <linux/jiffies.h>
39#include <linux/i2c.h>
40#include <linux/hwmon.h>
41#include <linux/hwmon-sysfs.h>
42#include <linux/err.h>
43#include <linux/mutex.h>
44#include <linux/sysfs.h>
45
46static const unsigned short normal_i2c[] = {
47 0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
48
49/*
50 * The MAX6642 registers
51 */
52
53#define MAX6642_REG_R_MAN_ID 0xFE
54#define MAX6642_REG_R_CONFIG 0x03
55#define MAX6642_REG_W_CONFIG 0x09
56#define MAX6642_REG_R_STATUS 0x02
57#define MAX6642_REG_R_LOCAL_TEMP 0x00
58#define MAX6642_REG_R_LOCAL_TEMPL 0x11
59#define MAX6642_REG_R_LOCAL_HIGH 0x05
60#define MAX6642_REG_W_LOCAL_HIGH 0x0B
61#define MAX6642_REG_R_REMOTE_TEMP 0x01
62#define MAX6642_REG_R_REMOTE_TEMPL 0x10
63#define MAX6642_REG_R_REMOTE_HIGH 0x07
64#define MAX6642_REG_W_REMOTE_HIGH 0x0D
65
66/*
67 * Conversions
68 */
69
70static int temp_from_reg10(int val)
71{
72 return val * 250;
73}
74
75static int temp_from_reg(int val)
76{
77 return val * 1000;
78}
79
80static int temp_to_reg(int val)
81{
82 return val / 1000;
83}
84
85/*
86 * Client data (each client gets its own)
87 */
88
89struct max6642_data {
90 struct i2c_client *client;
91 struct mutex update_lock;
92 bool valid; /* zero until following fields are valid */
93 unsigned long last_updated; /* in jiffies */
94
95 /* registers values */
96 u16 temp_input[2]; /* local/remote */
97 u16 temp_high[2]; /* local/remote */
98 u8 alarms;
99};
100
101/*
102 * Real code
103 */
104
105static void max6642_init_client(struct max6642_data *data,
106 struct i2c_client *client)
107{
108 u8 config;
109
110 /*
111 * Start the conversions.
112 */
113 config = i2c_smbus_read_byte_data(client, MAX6642_REG_R_CONFIG);
114 if (config & 0x40)
115 i2c_smbus_write_byte_data(client, MAX6642_REG_W_CONFIG,
116 config & 0xBF); /* run */
117
118 data->temp_high[0] = i2c_smbus_read_byte_data(client,
119 MAX6642_REG_R_LOCAL_HIGH);
120 data->temp_high[1] = i2c_smbus_read_byte_data(client,
121 MAX6642_REG_R_REMOTE_HIGH);
122}
123
124/* Return 0 if detection is successful, -ENODEV otherwise */
125static int max6642_detect(struct i2c_client *client,
126 struct i2c_board_info *info)
127{
128 struct i2c_adapter *adapter = client->adapter;
129 u8 reg_config, reg_status, man_id;
130
131 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
132 return -ENODEV;
133
134 /* identification */
135 man_id = i2c_smbus_read_byte_data(client, MAX6642_REG_R_MAN_ID);
136 if (man_id != 0x4D)
137 return -ENODEV;
138
139 /* sanity check */
140 if (i2c_smbus_read_byte_data(client, 0x04) != 0x4D
141 || i2c_smbus_read_byte_data(client, 0x06) != 0x4D
142 || i2c_smbus_read_byte_data(client, 0xff) != 0x4D)
143 return -ENODEV;
144
145 /*
146 * We read the config and status register, the 4 lower bits in the
147 * config register should be zero and bit 5, 3, 1 and 0 should be
148 * zero in the status register.
149 */
150 reg_config = i2c_smbus_read_byte_data(client, MAX6642_REG_R_CONFIG);
151 if ((reg_config & 0x0f) != 0x00)
152 return -ENODEV;
153
154 /* in between, another round of sanity checks */
155 if (i2c_smbus_read_byte_data(client, 0x04) != reg_config
156 || i2c_smbus_read_byte_data(client, 0x06) != reg_config
157 || i2c_smbus_read_byte_data(client, 0xff) != reg_config)
158 return -ENODEV;
159
160 reg_status = i2c_smbus_read_byte_data(client, MAX6642_REG_R_STATUS);
161 if ((reg_status & 0x2b) != 0x00)
162 return -ENODEV;
163
164 strlcpy(info->type, "max6642", I2C_NAME_SIZE);
165
166 return 0;
167}
168
169static struct max6642_data *max6642_update_device(struct device *dev)
170{
171 struct max6642_data *data = dev_get_drvdata(dev);
172 struct i2c_client *client = data->client;
173 u16 val, tmp;
174
175 mutex_lock(&data->update_lock);
176
177 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
178 dev_dbg(dev, "Updating max6642 data.\n");
179 val = i2c_smbus_read_byte_data(client,
180 MAX6642_REG_R_LOCAL_TEMPL);
181 tmp = (val >> 6) & 3;
182 val = i2c_smbus_read_byte_data(client,
183 MAX6642_REG_R_LOCAL_TEMP);
184 val = (val << 2) | tmp;
185 data->temp_input[0] = val;
186 val = i2c_smbus_read_byte_data(client,
187 MAX6642_REG_R_REMOTE_TEMPL);
188 tmp = (val >> 6) & 3;
189 val = i2c_smbus_read_byte_data(client,
190 MAX6642_REG_R_REMOTE_TEMP);
191 val = (val << 2) | tmp;
192 data->temp_input[1] = val;
193 data->alarms = i2c_smbus_read_byte_data(client,
194 MAX6642_REG_R_STATUS);
195
196 data->last_updated = jiffies;
197 data->valid = 1;
198 }
199
200 mutex_unlock(&data->update_lock);
201
202 return data;
203}
204
205/*
206 * Sysfs stuff
207 */
208
209static ssize_t temp_max10_show(struct device *dev,
210 struct device_attribute *dev_attr, char *buf)
211{
212 struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
213 struct max6642_data *data = max6642_update_device(dev);
214
215 return sprintf(buf, "%d\n",
216 temp_from_reg10(data->temp_input[attr->index]));
217}
218
219static ssize_t temp_max_show(struct device *dev,
220 struct device_attribute *attr, char *buf)
221{
222 struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
223 struct max6642_data *data = max6642_update_device(dev);
224
225 return sprintf(buf, "%d\n", temp_from_reg(data->temp_high[attr2->nr]));
226}
227
228static ssize_t temp_max_store(struct device *dev,
229 struct device_attribute *attr, const char *buf,
230 size_t count)
231{
232 struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
233 struct max6642_data *data = dev_get_drvdata(dev);
234 unsigned long val;
235 int err;
236
237 err = kstrtoul(buf, 10, &val);
238 if (err < 0)
239 return err;
240
241 mutex_lock(&data->update_lock);
242 data->temp_high[attr2->nr] = clamp_val(temp_to_reg(val), 0, 255);
243 i2c_smbus_write_byte_data(data->client, attr2->index,
244 data->temp_high[attr2->nr]);
245 mutex_unlock(&data->update_lock);
246 return count;
247}
248
249static ssize_t alarm_show(struct device *dev, struct device_attribute *attr,
250 char *buf)
251{
252 int bitnr = to_sensor_dev_attr(attr)->index;
253 struct max6642_data *data = max6642_update_device(dev);
254 return sprintf(buf, "%d\n", (data->alarms >> bitnr) & 1);
255}
256
257static SENSOR_DEVICE_ATTR_RO(temp1_input, temp_max10, 0);
258static SENSOR_DEVICE_ATTR_RO(temp2_input, temp_max10, 1);
259static SENSOR_DEVICE_ATTR_2_RW(temp1_max, temp_max, 0,
260 MAX6642_REG_W_LOCAL_HIGH);
261static SENSOR_DEVICE_ATTR_2_RW(temp2_max, temp_max, 1,
262 MAX6642_REG_W_REMOTE_HIGH);
263static SENSOR_DEVICE_ATTR_RO(temp2_fault, alarm, 2);
264static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, 6);
265static SENSOR_DEVICE_ATTR_RO(temp2_max_alarm, alarm, 4);
266
267static struct attribute *max6642_attrs[] = {
268 &sensor_dev_attr_temp1_input.dev_attr.attr,
269 &sensor_dev_attr_temp2_input.dev_attr.attr,
270 &sensor_dev_attr_temp1_max.dev_attr.attr,
271 &sensor_dev_attr_temp2_max.dev_attr.attr,
272
273 &sensor_dev_attr_temp2_fault.dev_attr.attr,
274 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
275 &sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
276 NULL
277};
278ATTRIBUTE_GROUPS(max6642);
279
280static int max6642_probe(struct i2c_client *client,
281 const struct i2c_device_id *id)
282{
283 struct device *dev = &client->dev;
284 struct max6642_data *data;
285 struct device *hwmon_dev;
286
287 data = devm_kzalloc(dev, sizeof(struct max6642_data), GFP_KERNEL);
288 if (!data)
289 return -ENOMEM;
290
291 data->client = client;
292 mutex_init(&data->update_lock);
293
294 /* Initialize the MAX6642 chip */
295 max6642_init_client(data, client);
296
297 hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
298 client->name, data,
299 max6642_groups);
300 return PTR_ERR_OR_ZERO(hwmon_dev);
301}
302
303/*
304 * Driver data (common to all clients)
305 */
306
307static const struct i2c_device_id max6642_id[] = {
308 { "max6642", 0 },
309 { }
310};
311MODULE_DEVICE_TABLE(i2c, max6642_id);
312
313static struct i2c_driver max6642_driver = {
314 .class = I2C_CLASS_HWMON,
315 .driver = {
316 .name = "max6642",
317 },
318 .probe = max6642_probe,
319 .id_table = max6642_id,
320 .detect = max6642_detect,
321 .address_list = normal_i2c,
322};
323
324module_i2c_driver(max6642_driver);
325
326MODULE_AUTHOR("Per Dalen <per.dalen@appeartv.com>");
327MODULE_DESCRIPTION("MAX6642 sensor driver");
328MODULE_LICENSE("GPL");
329