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authorHans-Juergen Koch <hjk@linutronix.de>2007-05-08 11:22:00 -0400
committerJean Delvare <khali@hyperion.delvare>2007-05-08 11:22:00 -0400
commitd20620de0c3de622a9d6a841725bafaed6d1aec2 (patch)
tree5dbd1f0f04b44c0af6711b28a4fccc41b8bdaace /drivers
parente84cfbcbe830c20af030fd7ba37edf8ed88fda5f (diff)
hwmon: New max6650 driver
This driver supports the Maxim MAX6650 and MAX6651 fan speed monitoring and control chips. Signed-off-by: Hans J. Koch <hjk@linutronix.de> Signed-off-by: Jean Delvare <khali@linux-fr.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/hwmon/Kconfig10
-rw-r--r--drivers/hwmon/Makefile1
-rw-r--r--drivers/hwmon/max6650.c693
3 files changed, 704 insertions, 0 deletions
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 6362d02b18df..d89bd5eb50ae 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -375,6 +375,16 @@ config SENSORS_MAX1619
375 This driver can also be built as a module. If so, the module 375 This driver can also be built as a module. If so, the module
376 will be called max1619. 376 will be called max1619.
377 377
378config SENSORS_MAX6650
379 tristate "Maxim MAX6650 sensor chip"
380 depends on HWMON && I2C && EXPERIMENTAL
381 help
382 If you say yes here you get support for the MAX6650 / MAX6651
383 sensor chips.
384
385 This driver can also be built as a module. If so, the module
386 will be called max6650.
387
378config SENSORS_PC87360 388config SENSORS_PC87360
379 tristate "National Semiconductor PC87360 family" 389 tristate "National Semiconductor PC87360 family"
380 depends on HWMON && I2C && EXPERIMENTAL 390 depends on HWMON && I2C && EXPERIMENTAL
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 4165c27a2f25..bbbe86bf5da1 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -43,6 +43,7 @@ obj-$(CONFIG_SENSORS_LM87) += lm87.o
43obj-$(CONFIG_SENSORS_LM90) += lm90.o 43obj-$(CONFIG_SENSORS_LM90) += lm90.o
44obj-$(CONFIG_SENSORS_LM92) += lm92.o 44obj-$(CONFIG_SENSORS_LM92) += lm92.o
45obj-$(CONFIG_SENSORS_MAX1619) += max1619.o 45obj-$(CONFIG_SENSORS_MAX1619) += max1619.o
46obj-$(CONFIG_SENSORS_MAX6650) += max6650.o
46obj-$(CONFIG_SENSORS_PC87360) += pc87360.o 47obj-$(CONFIG_SENSORS_PC87360) += pc87360.o
47obj-$(CONFIG_SENSORS_PC87427) += pc87427.o 48obj-$(CONFIG_SENSORS_PC87427) += pc87427.o
48obj-$(CONFIG_SENSORS_SIS5595) += sis5595.o 49obj-$(CONFIG_SENSORS_SIS5595) += sis5595.o
diff --git a/drivers/hwmon/max6650.c b/drivers/hwmon/max6650.c
new file mode 100644
index 000000000000..8415664f33c2
--- /dev/null
+++ b/drivers/hwmon/max6650.c
@@ -0,0 +1,693 @@
1/*
2 * max6650.c - Part of lm_sensors, Linux kernel modules for hardware
3 * monitoring.
4 *
5 * (C) 2007 by Hans J. Koch <hjk@linutronix.de>
6 *
7 * based on code written by John Morris <john.morris@spirentcom.com>
8 * Copyright (c) 2003 Spirent Communications
9 * and Claus Gindhart <claus.gindhart@kontron.com>
10 *
11 * This module has only been tested with the MAX6650 chip. It should
12 * also work with the MAX6651. It does not distinguish max6650 and max6651
13 * chips.
14 *
15 * Tha datasheet was last seen at:
16 *
17 * http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.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#include <linux/module.h>
35#include <linux/init.h>
36#include <linux/slab.h>
37#include <linux/jiffies.h>
38#include <linux/i2c.h>
39#include <linux/hwmon.h>
40#include <linux/hwmon-sysfs.h>
41#include <linux/err.h>
42
43/*
44 * Addresses to scan. There are four disjoint possibilities, by pin config.
45 */
46
47static unsigned short normal_i2c[] = {0x1b, 0x1f, 0x48, 0x4b, I2C_CLIENT_END};
48
49/*
50 * Insmod parameters
51 */
52
53/* fan_voltage: 5=5V fan, 12=12V fan, 0=don't change */
54static int fan_voltage;
55/* prescaler: Possible values are 1, 2, 4, 8, 16 or 0 for don't change */
56static int prescaler;
57/* clock: The clock frequency of the chip the driver should assume */
58static int clock = 254000;
59
60module_param(fan_voltage, int, S_IRUGO);
61module_param(prescaler, int, S_IRUGO);
62module_param(clock, int, S_IRUGO);
63
64I2C_CLIENT_INSMOD_1(max6650);
65
66/*
67 * MAX 6650/6651 registers
68 */
69
70#define MAX6650_REG_SPEED 0x00
71#define MAX6650_REG_CONFIG 0x02
72#define MAX6650_REG_GPIO_DEF 0x04
73#define MAX6650_REG_DAC 0x06
74#define MAX6650_REG_ALARM_EN 0x08
75#define MAX6650_REG_ALARM 0x0A
76#define MAX6650_REG_TACH0 0x0C
77#define MAX6650_REG_TACH1 0x0E
78#define MAX6650_REG_TACH2 0x10
79#define MAX6650_REG_TACH3 0x12
80#define MAX6650_REG_GPIO_STAT 0x14
81#define MAX6650_REG_COUNT 0x16
82
83/*
84 * Config register bits
85 */
86
87#define MAX6650_CFG_V12 0x08
88#define MAX6650_CFG_PRESCALER_MASK 0x07
89#define MAX6650_CFG_PRESCALER_2 0x01
90#define MAX6650_CFG_PRESCALER_4 0x02
91#define MAX6650_CFG_PRESCALER_8 0x03
92#define MAX6650_CFG_PRESCALER_16 0x04
93#define MAX6650_CFG_MODE_MASK 0x30
94#define MAX6650_CFG_MODE_ON 0x00
95#define MAX6650_CFG_MODE_OFF 0x10
96#define MAX6650_CFG_MODE_CLOSED_LOOP 0x20
97#define MAX6650_CFG_MODE_OPEN_LOOP 0x30
98#define MAX6650_COUNT_MASK 0x03
99
100/* Minimum and maximum values of the FAN-RPM */
101#define FAN_RPM_MIN 240
102#define FAN_RPM_MAX 30000
103
104#define DIV_FROM_REG(reg) (1 << (reg & 7))
105
106static int max6650_attach_adapter(struct i2c_adapter *adapter);
107static int max6650_detect(struct i2c_adapter *adapter, int address, int kind);
108static int max6650_init_client(struct i2c_client *client);
109static int max6650_detach_client(struct i2c_client *client);
110static struct max6650_data *max6650_update_device(struct device *dev);
111
112/*
113 * Driver data (common to all clients)
114 */
115
116static struct i2c_driver max6650_driver = {
117 .driver = {
118 .name = "max6650",
119 },
120 .attach_adapter = max6650_attach_adapter,
121 .detach_client = max6650_detach_client,
122};
123
124/*
125 * Client data (each client gets its own)
126 */
127
128struct max6650_data
129{
130 struct i2c_client client;
131 struct class_device *class_dev;
132 struct mutex update_lock;
133 char valid; /* zero until following fields are valid */
134 unsigned long last_updated; /* in jiffies */
135
136 /* register values */
137 u8 speed;
138 u8 config;
139 u8 tach[4];
140 u8 count;
141 u8 dac;
142};
143
144static ssize_t get_fan(struct device *dev, struct device_attribute *devattr,
145 char *buf)
146{
147 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
148 struct max6650_data *data = max6650_update_device(dev);
149 int rpm;
150
151 /*
152 * Calculation details:
153 *
154 * Each tachometer counts over an interval given by the "count"
155 * register (0.25, 0.5, 1 or 2 seconds). This module assumes
156 * that the fans produce two pulses per revolution (this seems
157 * to be the most common).
158 */
159
160 rpm = ((data->tach[attr->index] * 120) / DIV_FROM_REG(data->count));
161 return sprintf(buf, "%d\n", rpm);
162}
163
164/*
165 * Set the fan speed to the specified RPM (or read back the RPM setting).
166 * This works in closed loop mode only. Use pwm1 for open loop speed setting.
167 *
168 * The MAX6650/1 will automatically control fan speed when in closed loop
169 * mode.
170 *
171 * Assumptions:
172 *
173 * 1) The MAX6650/1 internal 254kHz clock frequency is set correctly. Use
174 * the clock module parameter if you need to fine tune this.
175 *
176 * 2) The prescaler (low three bits of the config register) has already
177 * been set to an appropriate value. Use the prescaler module parameter
178 * if your BIOS doesn't initialize the chip properly.
179 *
180 * The relevant equations are given on pages 21 and 22 of the datasheet.
181 *
182 * From the datasheet, the relevant equation when in regulation is:
183 *
184 * [fCLK / (128 x (KTACH + 1))] = 2 x FanSpeed / KSCALE
185 *
186 * where:
187 *
188 * fCLK is the oscillator frequency (either the 254kHz internal
189 * oscillator or the externally applied clock)
190 *
191 * KTACH is the value in the speed register
192 *
193 * FanSpeed is the speed of the fan in rps
194 *
195 * KSCALE is the prescaler value (1, 2, 4, 8, or 16)
196 *
197 * When reading, we need to solve for FanSpeed. When writing, we need to
198 * solve for KTACH.
199 *
200 * Note: this tachometer is completely separate from the tachometers
201 * used to measure the fan speeds. Only one fan's speed (fan1) is
202 * controlled.
203 */
204
205static ssize_t get_target(struct device *dev, struct device_attribute *devattr,
206 char *buf)
207{
208 struct max6650_data *data = max6650_update_device(dev);
209 int kscale, ktach, rpm;
210
211 /*
212 * Use the datasheet equation:
213 *
214 * FanSpeed = KSCALE x fCLK / [256 x (KTACH + 1)]
215 *
216 * then multiply by 60 to give rpm.
217 */
218
219 kscale = DIV_FROM_REG(data->config);
220 ktach = data->speed;
221 rpm = 60 * kscale * clock / (256 * (ktach + 1));
222 return sprintf(buf, "%d\n", rpm);
223}
224
225static ssize_t set_target(struct device *dev, struct device_attribute *devattr,
226 const char *buf, size_t count)
227{
228 struct i2c_client *client = to_i2c_client(dev);
229 struct max6650_data *data = i2c_get_clientdata(client);
230 int rpm = simple_strtoul(buf, NULL, 10);
231 int kscale, ktach;
232
233 rpm = SENSORS_LIMIT(rpm, FAN_RPM_MIN, FAN_RPM_MAX);
234
235 /*
236 * Divide the required speed by 60 to get from rpm to rps, then
237 * use the datasheet equation:
238 *
239 * KTACH = [(fCLK x KSCALE) / (256 x FanSpeed)] - 1
240 */
241
242 mutex_lock(&data->update_lock);
243
244 kscale = DIV_FROM_REG(data->config);
245 ktach = ((clock * kscale) / (256 * rpm / 60)) - 1;
246 if (ktach < 0)
247 ktach = 0;
248 if (ktach > 255)
249 ktach = 255;
250 data->speed = ktach;
251
252 i2c_smbus_write_byte_data(client, MAX6650_REG_SPEED, data->speed);
253
254 mutex_unlock(&data->update_lock);
255
256 return count;
257}
258
259/*
260 * Get/set the fan speed in open loop mode using pwm1 sysfs file.
261 * Speed is given as a relative value from 0 to 255, where 255 is maximum
262 * speed. Note that this is done by writing directly to the chip's DAC,
263 * it won't change the closed loop speed set by fan1_target.
264 * Also note that due to rounding errors it is possible that you don't read
265 * back exactly the value you have set.
266 */
267
268static ssize_t get_pwm(struct device *dev, struct device_attribute *devattr,
269 char *buf)
270{
271 int pwm;
272 struct max6650_data *data = max6650_update_device(dev);
273
274 /* Useful range for dac is 0-180 for 12V fans and 0-76 for 5V fans.
275 Lower DAC values mean higher speeds. */
276 if (data->config & MAX6650_CFG_V12)
277 pwm = 255 - (255 * (int)data->dac)/180;
278 else
279 pwm = 255 - (255 * (int)data->dac)/76;
280
281 if (pwm < 0)
282 pwm = 0;
283
284 return sprintf(buf, "%d\n", pwm);
285}
286
287static ssize_t set_pwm(struct device *dev, struct device_attribute *devattr,
288 const char *buf, size_t count)
289{
290 struct i2c_client *client = to_i2c_client(dev);
291 struct max6650_data *data = i2c_get_clientdata(client);
292 int pwm = simple_strtoul(buf, NULL, 10);
293
294 pwm = SENSORS_LIMIT(pwm, 0, 255);
295
296 mutex_lock(&data->update_lock);
297
298 if (data->config & MAX6650_CFG_V12)
299 data->dac = 180 - (180 * pwm)/255;
300 else
301 data->dac = 76 - (76 * pwm)/255;
302
303 i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac);
304
305 mutex_unlock(&data->update_lock);
306
307 return count;
308}
309
310/*
311 * Get/Set controller mode:
312 * Possible values:
313 * 0 = Fan always on
314 * 1 = Open loop, Voltage is set according to speed, not regulated.
315 * 2 = Closed loop, RPM for all fans regulated by fan1 tachometer
316 */
317
318static ssize_t get_enable(struct device *dev, struct device_attribute *devattr,
319 char *buf)
320{
321 struct max6650_data *data = max6650_update_device(dev);
322 int mode = (data->config & MAX6650_CFG_MODE_MASK) >> 4;
323 int sysfs_modes[4] = {0, 1, 2, 1};
324
325 return sprintf(buf, "%d\n", sysfs_modes[mode]);
326}
327
328static ssize_t set_enable(struct device *dev, struct device_attribute *devattr,
329 const char *buf, size_t count)
330{
331 struct i2c_client *client = to_i2c_client(dev);
332 struct max6650_data *data = i2c_get_clientdata(client);
333 int mode = simple_strtoul(buf, NULL, 10);
334 int max6650_modes[3] = {0, 3, 2};
335
336 if ((mode < 0)||(mode > 2)) {
337 dev_err(&client->dev,
338 "illegal value for pwm1_enable (%d)\n", mode);
339 return -EINVAL;
340 }
341
342 mutex_lock(&data->update_lock);
343
344 data->config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
345 data->config = (data->config & ~MAX6650_CFG_MODE_MASK)
346 | (max6650_modes[mode] << 4);
347
348 i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, data->config);
349
350 mutex_unlock(&data->update_lock);
351
352 return count;
353}
354
355/*
356 * Read/write functions for fan1_div sysfs file. The MAX6650 has no such
357 * divider. We handle this by converting between divider and counttime:
358 *
359 * (counttime == k) <==> (divider == 2^k), k = 0, 1, 2, or 3
360 *
361 * Lower values of k allow to connect a faster fan without the risk of
362 * counter overflow. The price is lower resolution. You can also set counttime
363 * using the module parameter. Note that the module parameter "prescaler" also
364 * influences the behaviour. Unfortunately, there's no sysfs attribute
365 * defined for that. See the data sheet for details.
366 */
367
368static ssize_t get_div(struct device *dev, struct device_attribute *devattr,
369 char *buf)
370{
371 struct max6650_data *data = max6650_update_device(dev);
372
373 return sprintf(buf, "%d\n", DIV_FROM_REG(data->count));
374}
375
376static ssize_t set_div(struct device *dev, struct device_attribute *devattr,
377 const char *buf, size_t count)
378{
379 struct i2c_client *client = to_i2c_client(dev);
380 struct max6650_data *data = i2c_get_clientdata(client);
381 int div = simple_strtoul(buf, NULL, 10);
382
383 mutex_lock(&data->update_lock);
384 switch (div) {
385 case 1:
386 data->count = 0;
387 break;
388 case 2:
389 data->count = 1;
390 break;
391 case 4:
392 data->count = 2;
393 break;
394 case 8:
395 data->count = 3;
396 break;
397 default:
398 dev_err(&client->dev,
399 "illegal value for fan divider (%d)\n", div);
400 return -EINVAL;
401 }
402
403 i2c_smbus_write_byte_data(client, MAX6650_REG_COUNT, data->count);
404 mutex_unlock(&data->update_lock);
405
406 return count;
407}
408
409static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, get_fan, NULL, 0);
410static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, get_fan, NULL, 1);
411static SENSOR_DEVICE_ATTR(fan3_input, S_IRUGO, get_fan, NULL, 2);
412static SENSOR_DEVICE_ATTR(fan4_input, S_IRUGO, get_fan, NULL, 3);
413static DEVICE_ATTR(fan1_target, S_IWUSR | S_IRUGO, get_target, set_target);
414static DEVICE_ATTR(fan1_div, S_IWUSR | S_IRUGO, get_div, set_div);
415static DEVICE_ATTR(pwm1_enable, S_IWUSR | S_IRUGO, get_enable, set_enable);
416static DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, get_pwm, set_pwm);
417
418
419static struct attribute *max6650_attrs[] = {
420 &sensor_dev_attr_fan1_input.dev_attr.attr,
421 &sensor_dev_attr_fan2_input.dev_attr.attr,
422 &sensor_dev_attr_fan3_input.dev_attr.attr,
423 &sensor_dev_attr_fan4_input.dev_attr.attr,
424 &dev_attr_fan1_target.attr,
425 &dev_attr_fan1_div.attr,
426 &dev_attr_pwm1_enable.attr,
427 &dev_attr_pwm1.attr,
428 NULL
429};
430
431static struct attribute_group max6650_attr_grp = {
432 .attrs = max6650_attrs,
433};
434
435/*
436 * Real code
437 */
438
439static int max6650_attach_adapter(struct i2c_adapter *adapter)
440{
441 if (!(adapter->class & I2C_CLASS_HWMON)) {
442 dev_dbg(&adapter->dev,
443 "FATAL: max6650_attach_adapter class HWMON not set\n");
444 return 0;
445 }
446
447 return i2c_probe(adapter, &addr_data, max6650_detect);
448}
449
450/*
451 * The following function does more than just detection. If detection
452 * succeeds, it also registers the new chip.
453 */
454
455static int max6650_detect(struct i2c_adapter *adapter, int address, int kind)
456{
457 struct i2c_client *client;
458 struct max6650_data *data;
459 int err = -ENODEV;
460
461 dev_dbg(&adapter->dev, "max6650_detect called, kind = %d\n", kind);
462
463 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
464 dev_dbg(&adapter->dev, "max6650: I2C bus doesn't support "
465 "byte read mode, skipping.\n");
466 return 0;
467 }
468
469 if (!(data = kzalloc(sizeof(struct max6650_data), GFP_KERNEL))) {
470 dev_err(&adapter->dev, "max6650: out of memory.\n");
471 return -ENOMEM;
472 }
473
474 client = &data->client;
475 i2c_set_clientdata(client, data);
476 client->addr = address;
477 client->adapter = adapter;
478 client->driver = &max6650_driver;
479
480 /*
481 * Now we do the remaining detection. A negative kind means that
482 * the driver was loaded with no force parameter (default), so we
483 * must both detect and identify the chip (actually there is only
484 * one possible kind of chip for now, max6650). A zero kind means that
485 * the driver was loaded with the force parameter, the detection
486 * step shall be skipped. A positive kind means that the driver
487 * was loaded with the force parameter and a given kind of chip is
488 * requested, so both the detection and the identification steps
489 * are skipped.
490 *
491 * Currently I can find no way to distinguish between a MAX6650 and
492 * a MAX6651. This driver has only been tried on the former.
493 */
494
495 if ((kind < 0) &&
496 ( (i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG) & 0xC0)
497 ||(i2c_smbus_read_byte_data(client, MAX6650_REG_GPIO_STAT) & 0xE0)
498 ||(i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM_EN) & 0xE0)
499 ||(i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM) & 0xE0)
500 ||(i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT) & 0xFC))) {
501 dev_dbg(&adapter->dev,
502 "max6650: detection failed at 0x%02x.\n", address);
503 goto err_free;
504 }
505
506 dev_info(&adapter->dev, "max6650: chip found at 0x%02x.\n", address);
507
508 strlcpy(client->name, "max6650", I2C_NAME_SIZE);
509 mutex_init(&data->update_lock);
510
511 if ((err = i2c_attach_client(client))) {
512 dev_err(&adapter->dev, "max6650: failed to attach client.\n");
513 goto err_free;
514 }
515
516 /*
517 * Initialize the max6650 chip
518 */
519 if (max6650_init_client(client))
520 goto err_detach;
521
522 err = sysfs_create_group(&client->dev.kobj, &max6650_attr_grp);
523 if (err)
524 goto err_detach;
525
526 data->class_dev = hwmon_device_register(&client->dev);
527 if (!IS_ERR(data->class_dev))
528 return 0;
529
530 err = PTR_ERR(data->class_dev);
531 dev_err(&client->dev, "error registering hwmon device.\n");
532 sysfs_remove_group(&client->dev.kobj, &max6650_attr_grp);
533err_detach:
534 i2c_detach_client(client);
535err_free:
536 kfree(data);
537 return err;
538}
539
540static int max6650_detach_client(struct i2c_client *client)
541{
542 struct max6650_data *data = i2c_get_clientdata(client);
543 int err;
544
545 sysfs_remove_group(&client->dev.kobj, &max6650_attr_grp);
546 hwmon_device_unregister(data->class_dev);
547 err = i2c_detach_client(client);
548 if (!err)
549 kfree(data);
550 return err;
551}
552
553static int max6650_init_client(struct i2c_client *client)
554{
555 struct max6650_data *data = i2c_get_clientdata(client);
556 int config;
557 int err = -EIO;
558
559 config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
560
561 if (config < 0) {
562 dev_err(&client->dev, "Error reading config, aborting.\n");
563 return err;
564 }
565
566 switch (fan_voltage) {
567 case 0:
568 break;
569 case 5:
570 config &= ~MAX6650_CFG_V12;
571 break;
572 case 12:
573 config |= MAX6650_CFG_V12;
574 break;
575 default:
576 dev_err(&client->dev,
577 "illegal value for fan_voltage (%d)\n",
578 fan_voltage);
579 }
580
581 dev_info(&client->dev, "Fan voltage is set to %dV.\n",
582 (config & MAX6650_CFG_V12) ? 12 : 5);
583
584 switch (prescaler) {
585 case 0:
586 break;
587 case 1:
588 config &= ~MAX6650_CFG_PRESCALER_MASK;
589 break;
590 case 2:
591 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
592 | MAX6650_CFG_PRESCALER_2;
593 break;
594 case 4:
595 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
596 | MAX6650_CFG_PRESCALER_4;
597 break;
598 case 8:
599 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
600 | MAX6650_CFG_PRESCALER_8;
601 break;
602 case 16:
603 config = (config & ~MAX6650_CFG_PRESCALER_MASK)
604 | MAX6650_CFG_PRESCALER_16;
605 break;
606 default:
607 dev_err(&client->dev,
608 "illegal value for prescaler (%d)\n",
609 prescaler);
610 }
611
612 dev_info(&client->dev, "Prescaler is set to %d.\n",
613 1 << (config & MAX6650_CFG_PRESCALER_MASK));
614
615 /* If mode is set to "full off", we change it to "open loop" and
616 * set DAC to 255, which has the same effect. We do this because
617 * there's no "full off" mode defined in hwmon specifcations.
618 */
619
620 if ((config & MAX6650_CFG_MODE_MASK) == MAX6650_CFG_MODE_OFF) {
621 dev_dbg(&client->dev, "Change mode to open loop, full off.\n");
622 config = (config & ~MAX6650_CFG_MODE_MASK)
623 | MAX6650_CFG_MODE_OPEN_LOOP;
624 if (i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, 255)) {
625 dev_err(&client->dev, "DAC write error, aborting.\n");
626 return err;
627 }
628 }
629
630 if (i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, config)) {
631 dev_err(&client->dev, "Config write error, aborting.\n");
632 return err;
633 }
634
635 data->config = config;
636 data->count = i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT);
637
638 return 0;
639}
640
641static const u8 tach_reg[] = {
642 MAX6650_REG_TACH0,
643 MAX6650_REG_TACH1,
644 MAX6650_REG_TACH2,
645 MAX6650_REG_TACH3,
646};
647
648static struct max6650_data *max6650_update_device(struct device *dev)
649{
650 int i;
651 struct i2c_client *client = to_i2c_client(dev);
652 struct max6650_data *data = i2c_get_clientdata(client);
653
654 mutex_lock(&data->update_lock);
655
656 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
657 data->speed = i2c_smbus_read_byte_data(client,
658 MAX6650_REG_SPEED);
659 data->config = i2c_smbus_read_byte_data(client,
660 MAX6650_REG_CONFIG);
661 for (i = 0; i < 4; i++) {
662 data->tach[i] = i2c_smbus_read_byte_data(client,
663 tach_reg[i]);
664 }
665 data->count = i2c_smbus_read_byte_data(client,
666 MAX6650_REG_COUNT);
667 data->dac = i2c_smbus_read_byte_data(client, MAX6650_REG_DAC);
668
669 data->last_updated = jiffies;
670 data->valid = 1;
671 }
672
673 mutex_unlock(&data->update_lock);
674
675 return data;
676}
677
678static int __init sensors_max6650_init(void)
679{
680 return i2c_add_driver(&max6650_driver);
681}
682
683static void __exit sensors_max6650_exit(void)
684{
685 i2c_del_driver(&max6650_driver);
686}
687
688MODULE_AUTHOR("Hans J. Koch");
689MODULE_DESCRIPTION("MAX6650 sensor driver");
690MODULE_LICENSE("GPL");
691
692module_init(sensors_max6650_init);
693module_exit(sensors_max6650_exit);