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Linux 3.12.39
[linux/fpc-iii.git] / drivers / hwmon / ltc4245.c
blobcdc1ecc6734d4122f9aab8736f5b4f37217aaf6b
1 /*
2 * Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller
3 *
4 * Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; version 2 of the License.
9 *
10 * This driver is based on the ds1621 and ina209 drivers.
11 *
12 * Datasheet:
13 * http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1140,P19392,D13517
14 */
15
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include <linux/err.h>
20 #include <linux/slab.h>
21 #include <linux/i2c.h>
22 #include <linux/hwmon.h>
23 #include <linux/hwmon-sysfs.h>
24 #include <linux/jiffies.h>
25 #include <linux/i2c/ltc4245.h>
26
27 /* Here are names of the chip's registers (a.k.a. commands) */
28 enum ltc4245_cmd {
29 LTC4245_STATUS = 0x00, /* readonly */
30 LTC4245_ALERT = 0x01,
31 LTC4245_CONTROL = 0x02,
32 LTC4245_ON = 0x03,
33 LTC4245_FAULT1 = 0x04,
34 LTC4245_FAULT2 = 0x05,
35 LTC4245_GPIO = 0x06,
36 LTC4245_ADCADR = 0x07,
37
38 LTC4245_12VIN = 0x10,
39 LTC4245_12VSENSE = 0x11,
40 LTC4245_12VOUT = 0x12,
41 LTC4245_5VIN = 0x13,
42 LTC4245_5VSENSE = 0x14,
43 LTC4245_5VOUT = 0x15,
44 LTC4245_3VIN = 0x16,
45 LTC4245_3VSENSE = 0x17,
46 LTC4245_3VOUT = 0x18,
47 LTC4245_VEEIN = 0x19,
48 LTC4245_VEESENSE = 0x1a,
49 LTC4245_VEEOUT = 0x1b,
50 LTC4245_GPIOADC = 0x1c,
51 };
52
53 struct ltc4245_data {
54 struct device *hwmon_dev;
55
56 struct mutex update_lock;
57 bool valid;
58 unsigned long last_updated; /* in jiffies */
59
60 /* Control registers */
61 u8 cregs[0x08];
62
63 /* Voltage registers */
64 u8 vregs[0x0d];
65
66 /* GPIO ADC registers */
67 bool use_extra_gpios;
68 int gpios[3];
69 };
70
71 /*
72 * Update the readings from the GPIO pins. If the driver has been configured to
73 * sample all GPIO's as analog voltages, a round-robin sampling method is used.
74 * Otherwise, only the configured GPIO pin is sampled.
75 *
76 * LOCKING: must hold data->update_lock
77 */
78 static void ltc4245_update_gpios(struct device *dev)
79 {
80 struct i2c_client *client = to_i2c_client(dev);
81 struct ltc4245_data *data = i2c_get_clientdata(client);
82 u8 gpio_curr, gpio_next, gpio_reg;
83 int i;
84
85 /* no extra gpio support, we're basically done */
86 if (!data->use_extra_gpios) {
87 data->gpios[0] = data->vregs[LTC4245_GPIOADC - 0x10];
88 return;
89 }
90
91 /*
92 * If the last reading was too long ago, then we mark all old GPIO
93 * readings as stale by setting them to -EAGAIN
94 */
95 if (time_after(jiffies, data->last_updated + 5 * HZ)) {
96 dev_dbg(&client->dev, "Marking GPIOs invalid\n");
97 for (i = 0; i < ARRAY_SIZE(data->gpios); i++)
98 data->gpios[i] = -EAGAIN;
99 }
100
101 /*
102 * Get the current GPIO pin
103 *
104 * The datasheet calls these GPIO[1-3], but we'll calculate the zero
105 * based array index instead, and call them GPIO[0-2]. This is much
106 * easier to think about.
107 */
108 gpio_curr = (data->cregs[LTC4245_GPIO] & 0xc0) >> 6;
109 if (gpio_curr > 0)
110 gpio_curr -= 1;
111
112 /* Read the GPIO voltage from the GPIOADC register */
113 data->gpios[gpio_curr] = data->vregs[LTC4245_GPIOADC - 0x10];
114
115 /* Find the next GPIO pin to read */
116 gpio_next = (gpio_curr + 1) % ARRAY_SIZE(data->gpios);
117
118 /*
119 * Calculate the correct setting for the GPIO register so it will
120 * sample the next GPIO pin
121 */
122 gpio_reg = (data->cregs[LTC4245_GPIO] & 0x3f) | ((gpio_next + 1) << 6);
123
124 /* Update the GPIO register */
125 i2c_smbus_write_byte_data(client, LTC4245_GPIO, gpio_reg);
126
127 /* Update saved data */
128 data->cregs[LTC4245_GPIO] = gpio_reg;
129 }
130
131 static struct ltc4245_data *ltc4245_update_device(struct device *dev)
132 {
133 struct i2c_client *client = to_i2c_client(dev);
134 struct ltc4245_data *data = i2c_get_clientdata(client);
135 s32 val;
136 int i;
137
138 mutex_lock(&data->update_lock);
139
140 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
141
142 dev_dbg(&client->dev, "Starting ltc4245 update\n");
143
144 /* Read control registers -- 0x00 to 0x07 */
145 for (i = 0; i < ARRAY_SIZE(data->cregs); i++) {
146 val = i2c_smbus_read_byte_data(client, i);
147 if (unlikely(val < 0))
148 data->cregs[i] = 0;
149 else
150 data->cregs[i] = val;
151 }
152
153 /* Read voltage registers -- 0x10 to 0x1c */
154 for (i = 0; i < ARRAY_SIZE(data->vregs); i++) {
155 val = i2c_smbus_read_byte_data(client, i+0x10);
156 if (unlikely(val < 0))
157 data->vregs[i] = 0;
158 else
159 data->vregs[i] = val;
160 }
161
162 /* Update GPIO readings */
163 ltc4245_update_gpios(dev);
164
165 data->last_updated = jiffies;
166 data->valid = 1;
167 }
168
169 mutex_unlock(&data->update_lock);
170
171 return data;
172 }
173
174 /* Return the voltage from the given register in millivolts */
175 static int ltc4245_get_voltage(struct device *dev, u8 reg)
176 {
177 struct ltc4245_data *data = ltc4245_update_device(dev);
178 const u8 regval = data->vregs[reg - 0x10];
179 u32 voltage = 0;
180
181 switch (reg) {
182 case LTC4245_12VIN:
183 case LTC4245_12VOUT:
184 voltage = regval * 55;
185 break;
186 case LTC4245_5VIN:
187 case LTC4245_5VOUT:
188 voltage = regval * 22;
189 break;
190 case LTC4245_3VIN:
191 case LTC4245_3VOUT:
192 voltage = regval * 15;
193 break;
194 case LTC4245_VEEIN:
195 case LTC4245_VEEOUT:
196 voltage = regval * -55;
197 break;
198 case LTC4245_GPIOADC:
199 voltage = regval * 10;
200 break;
201 default:
202 /* If we get here, the developer messed up */
203 WARN_ON_ONCE(1);
204 break;
205 }
206
207 return voltage;
208 }
209
210 /* Return the current in the given sense register in milliAmperes */
211 static unsigned int ltc4245_get_current(struct device *dev, u8 reg)
212 {
213 struct ltc4245_data *data = ltc4245_update_device(dev);
214 const u8 regval = data->vregs[reg - 0x10];
215 unsigned int voltage;
216 unsigned int curr;
217
218 /*
219 * The strange looking conversions that follow are fixed-point
220 * math, since we cannot do floating point in the kernel.
221 *
222 * Step 1: convert sense register to microVolts
223 * Step 2: convert voltage to milliAmperes
224 *
225 * If you play around with the V=IR equation, you come up with
226 * the following: X uV / Y mOhm == Z mA
227 *
228 * With the resistors that are fractions of a milliOhm, we multiply
229 * the voltage and resistance by 10, to shift the decimal point.
230 * Now we can use the normal division operator again.
231 */
232
233 switch (reg) {
234 case LTC4245_12VSENSE:
235 voltage = regval * 250; /* voltage in uV */
236 curr = voltage / 50; /* sense resistor 50 mOhm */
237 break;
238 case LTC4245_5VSENSE:
239 voltage = regval * 125; /* voltage in uV */
240 curr = (voltage * 10) / 35; /* sense resistor 3.5 mOhm */
241 break;
242 case LTC4245_3VSENSE:
243 voltage = regval * 125; /* voltage in uV */
244 curr = (voltage * 10) / 25; /* sense resistor 2.5 mOhm */
245 break;
246 case LTC4245_VEESENSE:
247 voltage = regval * 250; /* voltage in uV */
248 curr = voltage / 100; /* sense resistor 100 mOhm */
249 break;
250 default:
251 /* If we get here, the developer messed up */
252 WARN_ON_ONCE(1);
253 curr = 0;
254 break;
255 }
256
257 return curr;
258 }
259
260 static ssize_t ltc4245_show_voltage(struct device *dev,
261 struct device_attribute *da,
262 char *buf)
263 {
264 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
265 const int voltage = ltc4245_get_voltage(dev, attr->index);
266
267 return snprintf(buf, PAGE_SIZE, "%d\n", voltage);
268 }
269
270 static ssize_t ltc4245_show_current(struct device *dev,
271 struct device_attribute *da,
272 char *buf)
273 {
274 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
275 const unsigned int curr = ltc4245_get_current(dev, attr->index);
276
277 return snprintf(buf, PAGE_SIZE, "%u\n", curr);
278 }
279
280 static ssize_t ltc4245_show_power(struct device *dev,
281 struct device_attribute *da,
282 char *buf)
283 {
284 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
285 const unsigned int curr = ltc4245_get_current(dev, attr->index);
286 const int output_voltage = ltc4245_get_voltage(dev, attr->index+1);
287
288 /* current in mA * voltage in mV == power in uW */
289 const unsigned int power = abs(output_voltage * curr);
290
291 return snprintf(buf, PAGE_SIZE, "%u\n", power);
292 }
293
294 static ssize_t ltc4245_show_alarm(struct device *dev,
295 struct device_attribute *da,
296 char *buf)
297 {
298 struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da);
299 struct ltc4245_data *data = ltc4245_update_device(dev);
300 const u8 reg = data->cregs[attr->index];
301 const u32 mask = attr->nr;
302
303 return snprintf(buf, PAGE_SIZE, "%u\n", (reg & mask) ? 1 : 0);
304 }
305
306 static ssize_t ltc4245_show_gpio(struct device *dev,
307 struct device_attribute *da,
308 char *buf)
309 {
310 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
311 struct ltc4245_data *data = ltc4245_update_device(dev);
312 int val = data->gpios[attr->index];
313
314 /* handle stale GPIO's */
315 if (val < 0)
316 return val;
317
318 /* Convert to millivolts and print */
319 return snprintf(buf, PAGE_SIZE, "%u\n", val * 10);
320 }
321
322 /* Construct a sensor_device_attribute structure for each register */
323
324 /* Input voltages */
325 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4245_show_voltage, NULL,
326 LTC4245_12VIN);
327 static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4245_show_voltage, NULL,
328 LTC4245_5VIN);
329 static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ltc4245_show_voltage, NULL,
330 LTC4245_3VIN);
331 static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ltc4245_show_voltage, NULL,
332 LTC4245_VEEIN);
333
334 /* Input undervoltage alarms */
335 static SENSOR_DEVICE_ATTR_2(in1_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
336 1 << 0, LTC4245_FAULT1);
337 static SENSOR_DEVICE_ATTR_2(in2_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
338 1 << 1, LTC4245_FAULT1);
339 static SENSOR_DEVICE_ATTR_2(in3_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
340 1 << 2, LTC4245_FAULT1);
341 static SENSOR_DEVICE_ATTR_2(in4_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
342 1 << 3, LTC4245_FAULT1);
343
344 /* Currents (via sense resistor) */
345 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4245_show_current, NULL,
346 LTC4245_12VSENSE);
347 static SENSOR_DEVICE_ATTR(curr2_input, S_IRUGO, ltc4245_show_current, NULL,
348 LTC4245_5VSENSE);
349 static SENSOR_DEVICE_ATTR(curr3_input, S_IRUGO, ltc4245_show_current, NULL,
350 LTC4245_3VSENSE);
351 static SENSOR_DEVICE_ATTR(curr4_input, S_IRUGO, ltc4245_show_current, NULL,
352 LTC4245_VEESENSE);
353
354 /* Overcurrent alarms */
355 static SENSOR_DEVICE_ATTR_2(curr1_max_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
356 1 << 4, LTC4245_FAULT1);
357 static SENSOR_DEVICE_ATTR_2(curr2_max_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
358 1 << 5, LTC4245_FAULT1);
359 static SENSOR_DEVICE_ATTR_2(curr3_max_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
360 1 << 6, LTC4245_FAULT1);
361 static SENSOR_DEVICE_ATTR_2(curr4_max_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
362 1 << 7, LTC4245_FAULT1);
363
364 /* Output voltages */
365 static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, ltc4245_show_voltage, NULL,
366 LTC4245_12VOUT);
367 static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, ltc4245_show_voltage, NULL,
368 LTC4245_5VOUT);
369 static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, ltc4245_show_voltage, NULL,
370 LTC4245_3VOUT);
371 static SENSOR_DEVICE_ATTR(in8_input, S_IRUGO, ltc4245_show_voltage, NULL,
372 LTC4245_VEEOUT);
373
374 /* Power Bad alarms */
375 static SENSOR_DEVICE_ATTR_2(in5_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
376 1 << 0, LTC4245_FAULT2);
377 static SENSOR_DEVICE_ATTR_2(in6_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
378 1 << 1, LTC4245_FAULT2);
379 static SENSOR_DEVICE_ATTR_2(in7_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
380 1 << 2, LTC4245_FAULT2);
381 static SENSOR_DEVICE_ATTR_2(in8_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL,
382 1 << 3, LTC4245_FAULT2);
383
384 /* GPIO voltages */
385 static SENSOR_DEVICE_ATTR(in9_input, S_IRUGO, ltc4245_show_gpio, NULL, 0);
386 static SENSOR_DEVICE_ATTR(in10_input, S_IRUGO, ltc4245_show_gpio, NULL, 1);
387 static SENSOR_DEVICE_ATTR(in11_input, S_IRUGO, ltc4245_show_gpio, NULL, 2);
388
389 /* Power Consumption (virtual) */
390 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ltc4245_show_power, NULL,
391 LTC4245_12VSENSE);
392 static SENSOR_DEVICE_ATTR(power2_input, S_IRUGO, ltc4245_show_power, NULL,
393 LTC4245_5VSENSE);
394 static SENSOR_DEVICE_ATTR(power3_input, S_IRUGO, ltc4245_show_power, NULL,
395 LTC4245_3VSENSE);
396 static SENSOR_DEVICE_ATTR(power4_input, S_IRUGO, ltc4245_show_power, NULL,
397 LTC4245_VEESENSE);
398
399 /*
400 * Finally, construct an array of pointers to members of the above objects,
401 * as required for sysfs_create_group()
402 */
403 static struct attribute *ltc4245_std_attributes[] = {
404 &sensor_dev_attr_in1_input.dev_attr.attr,
405 &sensor_dev_attr_in2_input.dev_attr.attr,
406 &sensor_dev_attr_in3_input.dev_attr.attr,
407 &sensor_dev_attr_in4_input.dev_attr.attr,
408
409 &sensor_dev_attr_in1_min_alarm.dev_attr.attr,
410 &sensor_dev_attr_in2_min_alarm.dev_attr.attr,
411 &sensor_dev_attr_in3_min_alarm.dev_attr.attr,
412 &sensor_dev_attr_in4_min_alarm.dev_attr.attr,
413
414 &sensor_dev_attr_curr1_input.dev_attr.attr,
415 &sensor_dev_attr_curr2_input.dev_attr.attr,
416 &sensor_dev_attr_curr3_input.dev_attr.attr,
417 &sensor_dev_attr_curr4_input.dev_attr.attr,
418
419 &sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
420 &sensor_dev_attr_curr2_max_alarm.dev_attr.attr,
421 &sensor_dev_attr_curr3_max_alarm.dev_attr.attr,
422 &sensor_dev_attr_curr4_max_alarm.dev_attr.attr,
423
424 &sensor_dev_attr_in5_input.dev_attr.attr,
425 &sensor_dev_attr_in6_input.dev_attr.attr,
426 &sensor_dev_attr_in7_input.dev_attr.attr,
427 &sensor_dev_attr_in8_input.dev_attr.attr,
428
429 &sensor_dev_attr_in5_min_alarm.dev_attr.attr,
430 &sensor_dev_attr_in6_min_alarm.dev_attr.attr,
431 &sensor_dev_attr_in7_min_alarm.dev_attr.attr,
432 &sensor_dev_attr_in8_min_alarm.dev_attr.attr,
433
434 &sensor_dev_attr_in9_input.dev_attr.attr,
435
436 &sensor_dev_attr_power1_input.dev_attr.attr,
437 &sensor_dev_attr_power2_input.dev_attr.attr,
438 &sensor_dev_attr_power3_input.dev_attr.attr,
439 &sensor_dev_attr_power4_input.dev_attr.attr,
440
441 NULL,
442 };
443
444 static struct attribute *ltc4245_gpio_attributes[] = {
445 &sensor_dev_attr_in10_input.dev_attr.attr,
446 &sensor_dev_attr_in11_input.dev_attr.attr,
447 NULL,
448 };
449
450 static const struct attribute_group ltc4245_std_group = {
451 .attrs = ltc4245_std_attributes,
452 };
453
454 static const struct attribute_group ltc4245_gpio_group = {
455 .attrs = ltc4245_gpio_attributes,
456 };
457
458 static int ltc4245_sysfs_create_groups(struct i2c_client *client)
459 {
460 struct ltc4245_data *data = i2c_get_clientdata(client);
461 struct device *dev = &client->dev;
462 int ret;
463
464 /* register the standard sysfs attributes */
465 ret = sysfs_create_group(&dev->kobj, &ltc4245_std_group);
466 if (ret) {
467 dev_err(dev, "unable to register standard attributes\n");
468 return ret;
469 }
470
471 /* if we're using the extra gpio support, register it's attributes */
472 if (data->use_extra_gpios) {
473 ret = sysfs_create_group(&dev->kobj, &ltc4245_gpio_group);
474 if (ret) {
475 dev_err(dev, "unable to register gpio attributes\n");
476 sysfs_remove_group(&dev->kobj, &ltc4245_std_group);
477 return ret;
478 }
479 }
480
481 return 0;
482 }
483
484 static void ltc4245_sysfs_remove_groups(struct i2c_client *client)
485 {
486 struct ltc4245_data *data = i2c_get_clientdata(client);
487 struct device *dev = &client->dev;
488
489 if (data->use_extra_gpios)
490 sysfs_remove_group(&dev->kobj, &ltc4245_gpio_group);
491
492 sysfs_remove_group(&dev->kobj, &ltc4245_std_group);
493 }
494
495 static bool ltc4245_use_extra_gpios(struct i2c_client *client)
496 {
497 struct ltc4245_platform_data *pdata = dev_get_platdata(&client->dev);
498 #ifdef CONFIG_OF
499 struct device_node *np = client->dev.of_node;
500 #endif
501
502 /* prefer platform data */
503 if (pdata)
504 return pdata->use_extra_gpios;
505
506 #ifdef CONFIG_OF
507 /* fallback on OF */
508 if (of_find_property(np, "ltc4245,use-extra-gpios", NULL))
509 return true;
510 #endif
511
512 return false;
513 }
514
515 static int ltc4245_probe(struct i2c_client *client,
516 const struct i2c_device_id *id)
517 {
518 struct i2c_adapter *adapter = client->adapter;
519 struct ltc4245_data *data;
520 int ret;
521
522 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
523 return -ENODEV;
524
525 data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
526 if (!data)
527 return -ENOMEM;
528
529 i2c_set_clientdata(client, data);
530 mutex_init(&data->update_lock);
531 data->use_extra_gpios = ltc4245_use_extra_gpios(client);
532
533 /* Initialize the LTC4245 chip */
534 i2c_smbus_write_byte_data(client, LTC4245_FAULT1, 0x00);
535 i2c_smbus_write_byte_data(client, LTC4245_FAULT2, 0x00);
536
537 /* Register sysfs hooks */
538 ret = ltc4245_sysfs_create_groups(client);
539 if (ret)
540 return ret;
541
542 data->hwmon_dev = hwmon_device_register(&client->dev);
543 if (IS_ERR(data->hwmon_dev)) {
544 ret = PTR_ERR(data->hwmon_dev);
545 goto out_hwmon_device_register;
546 }
547
548 return 0;
549
550 out_hwmon_device_register:
551 ltc4245_sysfs_remove_groups(client);
552 return ret;
553 }
554
555 static int ltc4245_remove(struct i2c_client *client)
556 {
557 struct ltc4245_data *data = i2c_get_clientdata(client);
558
559 hwmon_device_unregister(data->hwmon_dev);
560 ltc4245_sysfs_remove_groups(client);
561
562 return 0;
563 }
564
565 static const struct i2c_device_id ltc4245_id[] = {
566 { "ltc4245", 0 },
567 { }
568 };
569 MODULE_DEVICE_TABLE(i2c, ltc4245_id);
570
571 /* This is the driver that will be inserted */
572 static struct i2c_driver ltc4245_driver = {
573 .driver = {
574 .name = "ltc4245",
575 },
576 .probe = ltc4245_probe,
577 .remove = ltc4245_remove,
578 .id_table = ltc4245_id,
579 };
580
581 module_i2c_driver(ltc4245_driver);
582
583 MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
584 MODULE_DESCRIPTION("LTC4245 driver");
585 MODULE_LICENSE("GPL");
Linux with added FPC-III support