1/*
2 * tc654.c - Linux kernel modules for fan speed controller
3 *
4 * Copyright (C) 2016 Allied Telesis Labs NZ
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; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 */
16
17#include <linux/bitops.h>
18#include <linux/err.h>
19#include <linux/hwmon.h>
20#include <linux/hwmon-sysfs.h>
21#include <linux/i2c.h>
22#include <linux/init.h>
23#include <linux/jiffies.h>
24#include <linux/module.h>
25#include <linux/mutex.h>
26#include <linux/slab.h>
27#include <linux/util_macros.h>
28
29enum tc654_regs {
30 TC654_REG_RPM1 = 0x00, /* RPM Output 1 */
31 TC654_REG_RPM2 = 0x01, /* RPM Output 2 */
32 TC654_REG_FAN_FAULT1 = 0x02, /* Fan Fault 1 Threshold */
33 TC654_REG_FAN_FAULT2 = 0x03, /* Fan Fault 2 Threshold */
34 TC654_REG_CONFIG = 0x04, /* Configuration */
35 TC654_REG_STATUS = 0x05, /* Status */
36 TC654_REG_DUTY_CYCLE = 0x06, /* Fan Speed Duty Cycle */
37 TC654_REG_MFR_ID = 0x07, /* Manufacturer Identification */
38 TC654_REG_VER_ID = 0x08, /* Version Identification */
39};
40
41/* Macros to easily index the registers */
42#define TC654_REG_RPM(idx) (TC654_REG_RPM1 + (idx))
43#define TC654_REG_FAN_FAULT(idx) (TC654_REG_FAN_FAULT1 + (idx))
44
45/* Config register bits */
46#define TC654_REG_CONFIG_RES BIT(6) /* Resolution Selection */
47#define TC654_REG_CONFIG_DUTYC BIT(5) /* Duty Cycle Control */
48#define TC654_REG_CONFIG_SDM BIT(0) /* Shutdown Mode */
49
50/* Status register bits */
51#define TC654_REG_STATUS_F2F BIT(1) /* Fan 2 Fault */
52#define TC654_REG_STATUS_F1F BIT(0) /* Fan 1 Fault */
53
54/* RPM resolution for RPM Output registers */
55#define TC654_HIGH_RPM_RESOLUTION 25 /* 25 RPM resolution */
56#define TC654_LOW_RPM_RESOLUTION 50 /* 50 RPM resolution */
57
58/* Convert to the fan fault RPM threshold from register value */
59#define TC654_FAN_FAULT_FROM_REG(val) ((val) * 50) /* 50 RPM resolution */
60
61/* Convert to register value from the fan fault RPM threshold */
62#define TC654_FAN_FAULT_TO_REG(val) (((val) / 50) & 0xff)
63
64/* Register data is read (and cached) at most once per second. */
65#define TC654_UPDATE_INTERVAL HZ
66
67struct tc654_data {
68 struct i2c_client *client;
69
70 /* update mutex */
71 struct mutex update_lock;
72
73 /* tc654 register cache */
74 bool valid;
75 unsigned long last_updated; /* in jiffies */
76
77 u8 rpm_output[2]; /* The fan RPM data for fans 1 and 2 is then
78 * written to registers RPM1 and RPM2
79 */
80 u8 fan_fault[2]; /* The Fan Fault Threshold Registers are used to
81 * set the fan fault threshold levels for fan 1
82 * and fan 2
83 */
84 u8 config; /* The Configuration Register is an 8-bit read/
85 * writable multi-function control register
86 * 7: Fan Fault Clear
87 * 1 = Clear Fan Fault
88 * 0 = Normal Operation (default)
89 * 6: Resolution Selection for RPM Output Registers
90 * RPM Output Registers (RPM1 and RPM2) will be
91 * set for
92 * 1 = 25 RPM (9-bit) resolution
93 * 0 = 50 RPM (8-bit) resolution (default)
94 * 5: Duty Cycle Control Method
95 * The V OUT duty cycle will be controlled via
96 * 1 = the SMBus interface.
97 * 0 = via the V IN analog input pin. (default)
98 * 4,3: Fan 2 Pulses Per Rotation
99 * 00 = 1
100 * 01 = 2 (default)
101 * 10 = 4
102 * 11 = 8
103 * 2,1: Fan 1 Pulses Per Rotation
104 * 00 = 1
105 * 01 = 2 (default)
106 * 10 = 4
107 * 11 = 8
108 * 0: Shutdown Mode
109 * 1 = Shutdown mode.
110 * 0 = Normal operation. (default)
111 */
112 u8 status; /* The Status register provides all the information
113 * about what is going on within the TC654/TC655
114 * devices.
115 * 7,6: Unimplemented, Read as '0'
116 * 5: Over-Temperature Fault Condition
117 * 1 = Over-Temperature condition has occurred
118 * 0 = Normal operation. V IN is less than 2.6V
119 * 4: RPM2 Counter Overflow
120 * 1 = Fault condition
121 * 0 = Normal operation
122 * 3: RPM1 Counter Overflow
123 * 1 = Fault condition
124 * 0 = Normal operation
125 * 2: V IN Input Status
126 * 1 = V IN is open
127 * 0 = Normal operation. voltage present at V IN
128 * 1: Fan 2 Fault
129 * 1 = Fault condition
130 * 0 = Normal operation
131 * 0: Fan 1 Fault
132 * 1 = Fault condition
133 * 0 = Normal operation
134 */
135 u8 duty_cycle; /* The DUTY_CYCLE register is a 4-bit read/
136 * writable register used to control the duty
137 * cycle of the V OUT output.
138 */
139};
140
141/* helper to grab and cache data, at most one time per second */
142static struct tc654_data *tc654_update_client(struct device *dev)
143{
144 struct tc654_data *data = dev_get_drvdata(dev);
145 struct i2c_client *client = data->client;
146 int ret = 0;
147
148 mutex_lock(&data->update_lock);
149 if (time_before(jiffies, data->last_updated + TC654_UPDATE_INTERVAL) &&
150 likely(data->valid))
151 goto out;
152
153 ret = i2c_smbus_read_byte_data(client, TC654_REG_RPM(0));
154 if (ret < 0)
155 goto out;
156 data->rpm_output[0] = ret;
157
158 ret = i2c_smbus_read_byte_data(client, TC654_REG_RPM(1));
159 if (ret < 0)
160 goto out;
161 data->rpm_output[1] = ret;
162
163 ret = i2c_smbus_read_byte_data(client, TC654_REG_FAN_FAULT(0));
164 if (ret < 0)
165 goto out;
166 data->fan_fault[0] = ret;
167
168 ret = i2c_smbus_read_byte_data(client, TC654_REG_FAN_FAULT(1));
169 if (ret < 0)
170 goto out;
171 data->fan_fault[1] = ret;
172
173 ret = i2c_smbus_read_byte_data(client, TC654_REG_CONFIG);
174 if (ret < 0)
175 goto out;
176 data->config = ret;
177
178 ret = i2c_smbus_read_byte_data(client, TC654_REG_STATUS);
179 if (ret < 0)
180 goto out;
181 data->status = ret;
182
183 ret = i2c_smbus_read_byte_data(client, TC654_REG_DUTY_CYCLE);
184 if (ret < 0)
185 goto out;
186 data->duty_cycle = ret & 0x0f;
187
188 data->last_updated = jiffies;
189 data->valid = true;
190out:
191 mutex_unlock(&data->update_lock);
192
193 if (ret < 0) /* upon error, encode it in return value */
194 data = ERR_PTR(ret);
195
196 return data;
197}
198
199/*
200 * sysfs attributes
201 */
202
203static ssize_t fan_show(struct device *dev, struct device_attribute *da,
204 char *buf)
205{
206 int nr = to_sensor_dev_attr(da)->index;
207 struct tc654_data *data = tc654_update_client(dev);
208 int val;
209
210 if (IS_ERR(data))
211 return PTR_ERR(data);
212
213 if (data->config & TC654_REG_CONFIG_RES)
214 val = data->rpm_output[nr] * TC654_HIGH_RPM_RESOLUTION;
215 else
216 val = data->rpm_output[nr] * TC654_LOW_RPM_RESOLUTION;
217
218 return sprintf(buf, "%d\n", val);
219}
220
221static ssize_t fan_min_show(struct device *dev, struct device_attribute *da,
222 char *buf)
223{
224 int nr = to_sensor_dev_attr(da)->index;
225 struct tc654_data *data = tc654_update_client(dev);
226
227 if (IS_ERR(data))
228 return PTR_ERR(data);
229
230 return sprintf(buf, "%d\n",
231 TC654_FAN_FAULT_FROM_REG(data->fan_fault[nr]));
232}
233
234static ssize_t fan_min_store(struct device *dev, struct device_attribute *da,
235 const char *buf, size_t count)
236{
237 int nr = to_sensor_dev_attr(da)->index;
238 struct tc654_data *data = dev_get_drvdata(dev);
239 struct i2c_client *client = data->client;
240 unsigned long val;
241 int ret;
242
243 if (kstrtoul(buf, 10, &val))
244 return -EINVAL;
245
246 val = clamp_val(val, 0, 12750);
247
248 mutex_lock(&data->update_lock);
249
250 data->fan_fault[nr] = TC654_FAN_FAULT_TO_REG(val);
251 ret = i2c_smbus_write_byte_data(client, TC654_REG_FAN_FAULT(nr),
252 data->fan_fault[nr]);
253
254 mutex_unlock(&data->update_lock);
255 return ret < 0 ? ret : count;
256}
257
258static ssize_t fan_alarm_show(struct device *dev, struct device_attribute *da,
259 char *buf)
260{
261 int nr = to_sensor_dev_attr(da)->index;
262 struct tc654_data *data = tc654_update_client(dev);
263 int val;
264
265 if (IS_ERR(data))
266 return PTR_ERR(data);
267
268 if (nr == 0)
269 val = !!(data->status & TC654_REG_STATUS_F1F);
270 else
271 val = !!(data->status & TC654_REG_STATUS_F2F);
272
273 return sprintf(buf, "%d\n", val);
274}
275
276static const u8 TC654_FAN_PULSE_SHIFT[] = { 1, 3 };
277
278static ssize_t fan_pulses_show(struct device *dev,
279 struct device_attribute *da, char *buf)
280{
281 int nr = to_sensor_dev_attr(da)->index;
282 struct tc654_data *data = tc654_update_client(dev);
283 u8 val;
284
285 if (IS_ERR(data))
286 return PTR_ERR(data);
287
288 val = BIT((data->config >> TC654_FAN_PULSE_SHIFT[nr]) & 0x03);
289 return sprintf(buf, "%d\n", val);
290}
291
292static ssize_t fan_pulses_store(struct device *dev,
293 struct device_attribute *da, const char *buf,
294 size_t count)
295{
296 int nr = to_sensor_dev_attr(da)->index;
297 struct tc654_data *data = dev_get_drvdata(dev);
298 struct i2c_client *client = data->client;
299 u8 config;
300 unsigned long val;
301 int ret;
302
303 if (kstrtoul(buf, 10, &val))
304 return -EINVAL;
305
306 switch (val) {
307 case 1:
308 config = 0;
309 break;
310 case 2:
311 config = 1;
312 break;
313 case 4:
314 config = 2;
315 break;
316 case 8:
317 config = 3;
318 break;
319 default:
320 return -EINVAL;
321 }
322
323 mutex_lock(&data->update_lock);
324
325 data->config &= ~(0x03 << TC654_FAN_PULSE_SHIFT[nr]);
326 data->config |= (config << TC654_FAN_PULSE_SHIFT[nr]);
327 ret = i2c_smbus_write_byte_data(client, TC654_REG_CONFIG, data->config);
328
329 mutex_unlock(&data->update_lock);
330 return ret < 0 ? ret : count;
331}
332
333static ssize_t pwm_mode_show(struct device *dev, struct device_attribute *da,
334 char *buf)
335{
336 struct tc654_data *data = tc654_update_client(dev);
337
338 if (IS_ERR(data))
339 return PTR_ERR(data);
340
341 return sprintf(buf, "%d\n", !!(data->config & TC654_REG_CONFIG_DUTYC));
342}
343
344static ssize_t pwm_mode_store(struct device *dev, struct device_attribute *da,
345 const char *buf, size_t count)
346{
347 struct tc654_data *data = dev_get_drvdata(dev);
348 struct i2c_client *client = data->client;
349 unsigned long val;
350 int ret;
351
352 if (kstrtoul(buf, 10, &val))
353 return -EINVAL;
354
355 if (val != 0 && val != 1)
356 return -EINVAL;
357
358 mutex_lock(&data->update_lock);
359
360 if (val)
361 data->config |= TC654_REG_CONFIG_DUTYC;
362 else
363 data->config &= ~TC654_REG_CONFIG_DUTYC;
364
365 ret = i2c_smbus_write_byte_data(client, TC654_REG_CONFIG, data->config);
366
367 mutex_unlock(&data->update_lock);
368 return ret < 0 ? ret : count;
369}
370
371static const int tc654_pwm_map[16] = { 77, 88, 102, 112, 124, 136, 148, 160,
372 172, 184, 196, 207, 219, 231, 243, 255};
373
374static ssize_t pwm_show(struct device *dev, struct device_attribute *da,
375 char *buf)
376{
377 struct tc654_data *data = tc654_update_client(dev);
378 int pwm;
379
380 if (IS_ERR(data))
381 return PTR_ERR(data);
382
383 if (data->config & TC654_REG_CONFIG_SDM)
384 pwm = 0;
385 else
386 pwm = tc654_pwm_map[data->duty_cycle];
387
388 return sprintf(buf, "%d\n", pwm);
389}
390
391static ssize_t pwm_store(struct device *dev, struct device_attribute *da,
392 const char *buf, size_t count)
393{
394 struct tc654_data *data = dev_get_drvdata(dev);
395 struct i2c_client *client = data->client;
396 unsigned long val;
397 int ret;
398
399 if (kstrtoul(buf, 10, &val))
400 return -EINVAL;
401 if (val > 255)
402 return -EINVAL;
403
404 mutex_lock(&data->update_lock);
405
406 if (val == 0)
407 data->config |= TC654_REG_CONFIG_SDM;
408 else
409 data->config &= ~TC654_REG_CONFIG_SDM;
410
411 data->duty_cycle = find_closest(val, tc654_pwm_map,
412 ARRAY_SIZE(tc654_pwm_map));
413
414 ret = i2c_smbus_write_byte_data(client, TC654_REG_CONFIG, data->config);
415 if (ret < 0)
416 goto out;
417
418 ret = i2c_smbus_write_byte_data(client, TC654_REG_DUTY_CYCLE,
419 data->duty_cycle);
420
421out:
422 mutex_unlock(&data->update_lock);
423 return ret < 0 ? ret : count;
424}
425
426static SENSOR_DEVICE_ATTR_RO(fan1_input, fan, 0);
427static SENSOR_DEVICE_ATTR_RO(fan2_input, fan, 1);
428static SENSOR_DEVICE_ATTR_RW(fan1_min, fan_min, 0);
429static SENSOR_DEVICE_ATTR_RW(fan2_min, fan_min, 1);
430static SENSOR_DEVICE_ATTR_RO(fan1_alarm, fan_alarm, 0);
431static SENSOR_DEVICE_ATTR_RO(fan2_alarm, fan_alarm, 1);
432static SENSOR_DEVICE_ATTR_RW(fan1_pulses, fan_pulses, 0);
433static SENSOR_DEVICE_ATTR_RW(fan2_pulses, fan_pulses, 1);
434static SENSOR_DEVICE_ATTR_RW(pwm1_mode, pwm_mode, 0);
435static SENSOR_DEVICE_ATTR_RW(pwm1, pwm, 0);
436
437/* Driver data */
438static struct attribute *tc654_attrs[] = {
439 &sensor_dev_attr_fan1_input.dev_attr.attr,
440 &sensor_dev_attr_fan2_input.dev_attr.attr,
441 &sensor_dev_attr_fan1_min.dev_attr.attr,
442 &sensor_dev_attr_fan2_min.dev_attr.attr,
443 &sensor_dev_attr_fan1_alarm.dev_attr.attr,
444 &sensor_dev_attr_fan2_alarm.dev_attr.attr,
445 &sensor_dev_attr_fan1_pulses.dev_attr.attr,
446 &sensor_dev_attr_fan2_pulses.dev_attr.attr,
447 &sensor_dev_attr_pwm1_mode.dev_attr.attr,
448 &sensor_dev_attr_pwm1.dev_attr.attr,
449 NULL
450};
451
452ATTRIBUTE_GROUPS(tc654);
453
454/*
455 * device probe and removal
456 */
457
458static int tc654_probe(struct i2c_client *client,
459 const struct i2c_device_id *id)
460{
461 struct device *dev = &client->dev;
462 struct tc654_data *data;
463 struct device *hwmon_dev;
464 int ret;
465
466 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
467 return -ENODEV;
468
469 data = devm_kzalloc(dev, sizeof(struct tc654_data), GFP_KERNEL);
470 if (!data)
471 return -ENOMEM;
472
473 data->client = client;
474 mutex_init(&data->update_lock);
475
476 ret = i2c_smbus_read_byte_data(client, TC654_REG_CONFIG);
477 if (ret < 0)
478 return ret;
479
480 data->config = ret;
481
482 hwmon_dev =
483 devm_hwmon_device_register_with_groups(dev, client->name, data,
484 tc654_groups);
485 return PTR_ERR_OR_ZERO(hwmon_dev);
486}
487
488static const struct i2c_device_id tc654_id[] = {
489 {"tc654", 0},
490 {"tc655", 0},
491 {}
492};
493
494MODULE_DEVICE_TABLE(i2c, tc654_id);
495
496static struct i2c_driver tc654_driver = {
497 .driver = {
498 .name = "tc654",
499 },
500 .probe = tc654_probe,
501 .id_table = tc654_id,
502};
503
504module_i2c_driver(tc654_driver);
505
506MODULE_AUTHOR("Allied Telesis Labs");
507MODULE_DESCRIPTION("Microchip TC654/TC655 driver");
508MODULE_LICENSE("GPL");
509