serial: xilinx_uartps: fix bad register write in console_write
[linux-2.6-xlnx.git] / drivers / hwmon / ltc4245.c
blobb99b45bafdad4d501e285c3d8b7cb1542a70477e
1 /*
2 * Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller
4 * Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu>
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.
10 * This driver is based on the ds1621 and ina209 drivers.
12 * Datasheet:
13 * http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1140,P19392,D13517
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/i2c/ltc4245.h>
26 /* Here are names of the chip's registers (a.k.a. commands) */
27 enum ltc4245_cmd {
28 LTC4245_STATUS = 0x00, /* readonly */
29 LTC4245_ALERT = 0x01,
30 LTC4245_CONTROL = 0x02,
31 LTC4245_ON = 0x03,
32 LTC4245_FAULT1 = 0x04,
33 LTC4245_FAULT2 = 0x05,
34 LTC4245_GPIO = 0x06,
35 LTC4245_ADCADR = 0x07,
37 LTC4245_12VIN = 0x10,
38 LTC4245_12VSENSE = 0x11,
39 LTC4245_12VOUT = 0x12,
40 LTC4245_5VIN = 0x13,
41 LTC4245_5VSENSE = 0x14,
42 LTC4245_5VOUT = 0x15,
43 LTC4245_3VIN = 0x16,
44 LTC4245_3VSENSE = 0x17,
45 LTC4245_3VOUT = 0x18,
46 LTC4245_VEEIN = 0x19,
47 LTC4245_VEESENSE = 0x1a,
48 LTC4245_VEEOUT = 0x1b,
49 LTC4245_GPIOADC = 0x1c,
52 struct ltc4245_data {
53 struct device *hwmon_dev;
55 struct mutex update_lock;
56 bool valid;
57 unsigned long last_updated; /* in jiffies */
59 /* Control registers */
60 u8 cregs[0x08];
62 /* Voltage registers */
63 u8 vregs[0x0d];
65 /* GPIO ADC registers */
66 bool use_extra_gpios;
67 int gpios[3];
71 * Update the readings from the GPIO pins. If the driver has been configured to
72 * sample all GPIO's as analog voltages, a round-robin sampling method is used.
73 * Otherwise, only the configured GPIO pin is sampled.
75 * LOCKING: must hold data->update_lock
77 static void ltc4245_update_gpios(struct device *dev)
79 struct i2c_client *client = to_i2c_client(dev);
80 struct ltc4245_data *data = i2c_get_clientdata(client);
81 u8 gpio_curr, gpio_next, gpio_reg;
82 int i;
84 /* no extra gpio support, we're basically done */
85 if (!data->use_extra_gpios) {
86 data->gpios[0] = data->vregs[LTC4245_GPIOADC - 0x10];
87 return;
91 * If the last reading was too long ago, then we mark all old GPIO
92 * readings as stale by setting them to -EAGAIN
94 if (time_after(jiffies, data->last_updated + 5 * HZ)) {
95 dev_dbg(&client->dev, "Marking GPIOs invalid\n");
96 for (i = 0; i < ARRAY_SIZE(data->gpios); i++)
97 data->gpios[i] = -EAGAIN;
101 * Get the current GPIO pin
103 * The datasheet calls these GPIO[1-3], but we'll calculate the zero
104 * based array index instead, and call them GPIO[0-2]. This is much
105 * easier to think about.
107 gpio_curr = (data->cregs[LTC4245_GPIO] & 0xc0) >> 6;
108 if (gpio_curr > 0)
109 gpio_curr -= 1;
111 /* Read the GPIO voltage from the GPIOADC register */
112 data->gpios[gpio_curr] = data->vregs[LTC4245_GPIOADC - 0x10];
114 /* Find the next GPIO pin to read */
115 gpio_next = (gpio_curr + 1) % ARRAY_SIZE(data->gpios);
118 * Calculate the correct setting for the GPIO register so it will
119 * sample the next GPIO pin
121 gpio_reg = (data->cregs[LTC4245_GPIO] & 0x3f) | ((gpio_next + 1) << 6);
123 /* Update the GPIO register */
124 i2c_smbus_write_byte_data(client, LTC4245_GPIO, gpio_reg);
126 /* Update saved data */
127 data->cregs[LTC4245_GPIO] = gpio_reg;
130 static struct ltc4245_data *ltc4245_update_device(struct device *dev)
132 struct i2c_client *client = to_i2c_client(dev);
133 struct ltc4245_data *data = i2c_get_clientdata(client);
134 s32 val;
135 int i;
137 mutex_lock(&data->update_lock);
139 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
141 dev_dbg(&client->dev, "Starting ltc4245 update\n");
143 /* Read control registers -- 0x00 to 0x07 */
144 for (i = 0; i < ARRAY_SIZE(data->cregs); i++) {
145 val = i2c_smbus_read_byte_data(client, i);
146 if (unlikely(val < 0))
147 data->cregs[i] = 0;
148 else
149 data->cregs[i] = val;
152 /* Read voltage registers -- 0x10 to 0x1c */
153 for (i = 0; i < ARRAY_SIZE(data->vregs); i++) {
154 val = i2c_smbus_read_byte_data(client, i+0x10);
155 if (unlikely(val < 0))
156 data->vregs[i] = 0;
157 else
158 data->vregs[i] = val;
161 /* Update GPIO readings */
162 ltc4245_update_gpios(dev);
164 data->last_updated = jiffies;
165 data->valid = 1;
168 mutex_unlock(&data->update_lock);
170 return data;
173 /* Return the voltage from the given register in millivolts */
174 static int ltc4245_get_voltage(struct device *dev, u8 reg)
176 struct ltc4245_data *data = ltc4245_update_device(dev);
177 const u8 regval = data->vregs[reg - 0x10];
178 u32 voltage = 0;
180 switch (reg) {
181 case LTC4245_12VIN:
182 case LTC4245_12VOUT:
183 voltage = regval * 55;
184 break;
185 case LTC4245_5VIN:
186 case LTC4245_5VOUT:
187 voltage = regval * 22;
188 break;
189 case LTC4245_3VIN:
190 case LTC4245_3VOUT:
191 voltage = regval * 15;
192 break;
193 case LTC4245_VEEIN:
194 case LTC4245_VEEOUT:
195 voltage = regval * -55;
196 break;
197 case LTC4245_GPIOADC:
198 voltage = regval * 10;
199 break;
200 default:
201 /* If we get here, the developer messed up */
202 WARN_ON_ONCE(1);
203 break;
206 return voltage;
209 /* Return the current in the given sense register in milliAmperes */
210 static unsigned int ltc4245_get_current(struct device *dev, u8 reg)
212 struct ltc4245_data *data = ltc4245_update_device(dev);
213 const u8 regval = data->vregs[reg - 0x10];
214 unsigned int voltage;
215 unsigned int curr;
218 * The strange looking conversions that follow are fixed-point
219 * math, since we cannot do floating point in the kernel.
221 * Step 1: convert sense register to microVolts
222 * Step 2: convert voltage to milliAmperes
224 * If you play around with the V=IR equation, you come up with
225 * the following: X uV / Y mOhm == Z mA
227 * With the resistors that are fractions of a milliOhm, we multiply
228 * the voltage and resistance by 10, to shift the decimal point.
229 * Now we can use the normal division operator again.
232 switch (reg) {
233 case LTC4245_12VSENSE:
234 voltage = regval * 250; /* voltage in uV */
235 curr = voltage / 50; /* sense resistor 50 mOhm */
236 break;
237 case LTC4245_5VSENSE:
238 voltage = regval * 125; /* voltage in uV */
239 curr = (voltage * 10) / 35; /* sense resistor 3.5 mOhm */
240 break;
241 case LTC4245_3VSENSE:
242 voltage = regval * 125; /* voltage in uV */
243 curr = (voltage * 10) / 25; /* sense resistor 2.5 mOhm */
244 break;
245 case LTC4245_VEESENSE:
246 voltage = regval * 250; /* voltage in uV */
247 curr = voltage / 100; /* sense resistor 100 mOhm */
248 break;
249 default:
250 /* If we get here, the developer messed up */
251 WARN_ON_ONCE(1);
252 curr = 0;
253 break;
256 return curr;
259 static ssize_t ltc4245_show_voltage(struct device *dev,
260 struct device_attribute *da,
261 char *buf)
263 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
264 const int voltage = ltc4245_get_voltage(dev, attr->index);
266 return snprintf(buf, PAGE_SIZE, "%d\n", voltage);
269 static ssize_t ltc4245_show_current(struct device *dev,
270 struct device_attribute *da,
271 char *buf)
273 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
274 const unsigned int curr = ltc4245_get_current(dev, attr->index);
276 return snprintf(buf, PAGE_SIZE, "%u\n", curr);
279 static ssize_t ltc4245_show_power(struct device *dev,
280 struct device_attribute *da,
281 char *buf)
283 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
284 const unsigned int curr = ltc4245_get_current(dev, attr->index);
285 const int output_voltage = ltc4245_get_voltage(dev, attr->index+1);
287 /* current in mA * voltage in mV == power in uW */
288 const unsigned int power = abs(output_voltage * curr);
290 return snprintf(buf, PAGE_SIZE, "%u\n", power);
293 static ssize_t ltc4245_show_alarm(struct device *dev,
294 struct device_attribute *da,
295 char *buf)
297 struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da);
298 struct ltc4245_data *data = ltc4245_update_device(dev);
299 const u8 reg = data->cregs[attr->index];
300 const u32 mask = attr->nr;
302 return snprintf(buf, PAGE_SIZE, "%u\n", (reg & mask) ? 1 : 0);
305 static ssize_t ltc4245_show_gpio(struct device *dev,
306 struct device_attribute *da,
307 char *buf)
309 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
310 struct ltc4245_data *data = ltc4245_update_device(dev);
311 int val = data->gpios[attr->index];
313 /* handle stale GPIO's */
314 if (val < 0)
315 return val;
317 /* Convert to millivolts and print */
318 return snprintf(buf, PAGE_SIZE, "%u\n", val * 10);
322 * These macros are used below in constructing device attribute objects
323 * for use with sysfs_create_group() to make a sysfs device file
324 * for each register.
327 #define LTC4245_VOLTAGE(name, ltc4245_cmd_idx) \
328 static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
329 ltc4245_show_voltage, NULL, ltc4245_cmd_idx)
331 #define LTC4245_CURRENT(name, ltc4245_cmd_idx) \
332 static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
333 ltc4245_show_current, NULL, ltc4245_cmd_idx)
335 #define LTC4245_POWER(name, ltc4245_cmd_idx) \
336 static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
337 ltc4245_show_power, NULL, ltc4245_cmd_idx)
339 #define LTC4245_ALARM(name, mask, reg) \
340 static SENSOR_DEVICE_ATTR_2(name, S_IRUGO, \
341 ltc4245_show_alarm, NULL, (mask), reg)
343 #define LTC4245_GPIO_VOLTAGE(name, gpio_num) \
344 static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
345 ltc4245_show_gpio, NULL, gpio_num)
347 /* Construct a sensor_device_attribute structure for each register */
349 /* Input voltages */
350 LTC4245_VOLTAGE(in1_input, LTC4245_12VIN);
351 LTC4245_VOLTAGE(in2_input, LTC4245_5VIN);
352 LTC4245_VOLTAGE(in3_input, LTC4245_3VIN);
353 LTC4245_VOLTAGE(in4_input, LTC4245_VEEIN);
355 /* Input undervoltage alarms */
356 LTC4245_ALARM(in1_min_alarm, (1 << 0), LTC4245_FAULT1);
357 LTC4245_ALARM(in2_min_alarm, (1 << 1), LTC4245_FAULT1);
358 LTC4245_ALARM(in3_min_alarm, (1 << 2), LTC4245_FAULT1);
359 LTC4245_ALARM(in4_min_alarm, (1 << 3), LTC4245_FAULT1);
361 /* Currents (via sense resistor) */
362 LTC4245_CURRENT(curr1_input, LTC4245_12VSENSE);
363 LTC4245_CURRENT(curr2_input, LTC4245_5VSENSE);
364 LTC4245_CURRENT(curr3_input, LTC4245_3VSENSE);
365 LTC4245_CURRENT(curr4_input, LTC4245_VEESENSE);
367 /* Overcurrent alarms */
368 LTC4245_ALARM(curr1_max_alarm, (1 << 4), LTC4245_FAULT1);
369 LTC4245_ALARM(curr2_max_alarm, (1 << 5), LTC4245_FAULT1);
370 LTC4245_ALARM(curr3_max_alarm, (1 << 6), LTC4245_FAULT1);
371 LTC4245_ALARM(curr4_max_alarm, (1 << 7), LTC4245_FAULT1);
373 /* Output voltages */
374 LTC4245_VOLTAGE(in5_input, LTC4245_12VOUT);
375 LTC4245_VOLTAGE(in6_input, LTC4245_5VOUT);
376 LTC4245_VOLTAGE(in7_input, LTC4245_3VOUT);
377 LTC4245_VOLTAGE(in8_input, LTC4245_VEEOUT);
379 /* Power Bad alarms */
380 LTC4245_ALARM(in5_min_alarm, (1 << 0), LTC4245_FAULT2);
381 LTC4245_ALARM(in6_min_alarm, (1 << 1), LTC4245_FAULT2);
382 LTC4245_ALARM(in7_min_alarm, (1 << 2), LTC4245_FAULT2);
383 LTC4245_ALARM(in8_min_alarm, (1 << 3), LTC4245_FAULT2);
385 /* GPIO voltages */
386 LTC4245_GPIO_VOLTAGE(in9_input, 0);
387 LTC4245_GPIO_VOLTAGE(in10_input, 1);
388 LTC4245_GPIO_VOLTAGE(in11_input, 2);
390 /* Power Consumption (virtual) */
391 LTC4245_POWER(power1_input, LTC4245_12VSENSE);
392 LTC4245_POWER(power2_input, LTC4245_5VSENSE);
393 LTC4245_POWER(power3_input, LTC4245_3VSENSE);
394 LTC4245_POWER(power4_input, LTC4245_VEESENSE);
397 * Finally, construct an array of pointers to members of the above objects,
398 * as required for sysfs_create_group()
400 static struct attribute *ltc4245_std_attributes[] = {
401 &sensor_dev_attr_in1_input.dev_attr.attr,
402 &sensor_dev_attr_in2_input.dev_attr.attr,
403 &sensor_dev_attr_in3_input.dev_attr.attr,
404 &sensor_dev_attr_in4_input.dev_attr.attr,
406 &sensor_dev_attr_in1_min_alarm.dev_attr.attr,
407 &sensor_dev_attr_in2_min_alarm.dev_attr.attr,
408 &sensor_dev_attr_in3_min_alarm.dev_attr.attr,
409 &sensor_dev_attr_in4_min_alarm.dev_attr.attr,
411 &sensor_dev_attr_curr1_input.dev_attr.attr,
412 &sensor_dev_attr_curr2_input.dev_attr.attr,
413 &sensor_dev_attr_curr3_input.dev_attr.attr,
414 &sensor_dev_attr_curr4_input.dev_attr.attr,
416 &sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
417 &sensor_dev_attr_curr2_max_alarm.dev_attr.attr,
418 &sensor_dev_attr_curr3_max_alarm.dev_attr.attr,
419 &sensor_dev_attr_curr4_max_alarm.dev_attr.attr,
421 &sensor_dev_attr_in5_input.dev_attr.attr,
422 &sensor_dev_attr_in6_input.dev_attr.attr,
423 &sensor_dev_attr_in7_input.dev_attr.attr,
424 &sensor_dev_attr_in8_input.dev_attr.attr,
426 &sensor_dev_attr_in5_min_alarm.dev_attr.attr,
427 &sensor_dev_attr_in6_min_alarm.dev_attr.attr,
428 &sensor_dev_attr_in7_min_alarm.dev_attr.attr,
429 &sensor_dev_attr_in8_min_alarm.dev_attr.attr,
431 &sensor_dev_attr_in9_input.dev_attr.attr,
433 &sensor_dev_attr_power1_input.dev_attr.attr,
434 &sensor_dev_attr_power2_input.dev_attr.attr,
435 &sensor_dev_attr_power3_input.dev_attr.attr,
436 &sensor_dev_attr_power4_input.dev_attr.attr,
438 NULL,
441 static struct attribute *ltc4245_gpio_attributes[] = {
442 &sensor_dev_attr_in10_input.dev_attr.attr,
443 &sensor_dev_attr_in11_input.dev_attr.attr,
444 NULL,
447 static const struct attribute_group ltc4245_std_group = {
448 .attrs = ltc4245_std_attributes,
451 static const struct attribute_group ltc4245_gpio_group = {
452 .attrs = ltc4245_gpio_attributes,
455 static int ltc4245_sysfs_create_groups(struct i2c_client *client)
457 struct ltc4245_data *data = i2c_get_clientdata(client);
458 struct device *dev = &client->dev;
459 int ret;
461 /* register the standard sysfs attributes */
462 ret = sysfs_create_group(&dev->kobj, &ltc4245_std_group);
463 if (ret) {
464 dev_err(dev, "unable to register standard attributes\n");
465 return ret;
468 /* if we're using the extra gpio support, register it's attributes */
469 if (data->use_extra_gpios) {
470 ret = sysfs_create_group(&dev->kobj, &ltc4245_gpio_group);
471 if (ret) {
472 dev_err(dev, "unable to register gpio attributes\n");
473 sysfs_remove_group(&dev->kobj, &ltc4245_std_group);
474 return ret;
478 return 0;
481 static void ltc4245_sysfs_remove_groups(struct i2c_client *client)
483 struct ltc4245_data *data = i2c_get_clientdata(client);
484 struct device *dev = &client->dev;
486 if (data->use_extra_gpios)
487 sysfs_remove_group(&dev->kobj, &ltc4245_gpio_group);
489 sysfs_remove_group(&dev->kobj, &ltc4245_std_group);
492 static bool ltc4245_use_extra_gpios(struct i2c_client *client)
494 struct ltc4245_platform_data *pdata = dev_get_platdata(&client->dev);
495 #ifdef CONFIG_OF
496 struct device_node *np = client->dev.of_node;
497 #endif
499 /* prefer platform data */
500 if (pdata)
501 return pdata->use_extra_gpios;
503 #ifdef CONFIG_OF
504 /* fallback on OF */
505 if (of_find_property(np, "ltc4245,use-extra-gpios", NULL))
506 return true;
507 #endif
509 return false;
512 static int ltc4245_probe(struct i2c_client *client,
513 const struct i2c_device_id *id)
515 struct i2c_adapter *adapter = client->adapter;
516 struct ltc4245_data *data;
517 int ret;
519 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
520 return -ENODEV;
522 data = kzalloc(sizeof(*data), GFP_KERNEL);
523 if (!data) {
524 ret = -ENOMEM;
525 goto out_kzalloc;
528 i2c_set_clientdata(client, data);
529 mutex_init(&data->update_lock);
530 data->use_extra_gpios = ltc4245_use_extra_gpios(client);
532 /* Initialize the LTC4245 chip */
533 i2c_smbus_write_byte_data(client, LTC4245_FAULT1, 0x00);
534 i2c_smbus_write_byte_data(client, LTC4245_FAULT2, 0x00);
536 /* Register sysfs hooks */
537 ret = ltc4245_sysfs_create_groups(client);
538 if (ret)
539 goto out_sysfs_create_groups;
541 data->hwmon_dev = hwmon_device_register(&client->dev);
542 if (IS_ERR(data->hwmon_dev)) {
543 ret = PTR_ERR(data->hwmon_dev);
544 goto out_hwmon_device_register;
547 return 0;
549 out_hwmon_device_register:
550 ltc4245_sysfs_remove_groups(client);
551 out_sysfs_create_groups:
552 kfree(data);
553 out_kzalloc:
554 return ret;
557 static int ltc4245_remove(struct i2c_client *client)
559 struct ltc4245_data *data = i2c_get_clientdata(client);
561 hwmon_device_unregister(data->hwmon_dev);
562 ltc4245_sysfs_remove_groups(client);
563 kfree(data);
565 return 0;
568 static const struct i2c_device_id ltc4245_id[] = {
569 { "ltc4245", 0 },
572 MODULE_DEVICE_TABLE(i2c, ltc4245_id);
574 /* This is the driver that will be inserted */
575 static struct i2c_driver ltc4245_driver = {
576 .driver = {
577 .name = "ltc4245",
579 .probe = ltc4245_probe,
580 .remove = ltc4245_remove,
581 .id_table = ltc4245_id,
584 module_i2c_driver(ltc4245_driver);
586 MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
587 MODULE_DESCRIPTION("LTC4245 driver");
588 MODULE_LICENSE("GPL");