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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * tc654.c - Linux kernel modules for fan speed controller
4 *
5 * Copyright (C) 2016 Allied Telesis Labs NZ
6 */
7
8#include <linux/bitops.h>
9#include <linux/err.h>
10#include <linux/hwmon.h>
11#include <linux/hwmon-sysfs.h>
12#include <linux/i2c.h>
13#include <linux/init.h>
14#include <linux/jiffies.h>
15#include <linux/module.h>
16#include <linux/mutex.h>
17#include <linux/slab.h>
18#include <linux/util_macros.h>
19
20enum tc654_regs {
21 TC654_REG_RPM1 = 0x00, /* RPM Output 1 */
22 TC654_REG_RPM2 = 0x01, /* RPM Output 2 */
23 TC654_REG_FAN_FAULT1 = 0x02, /* Fan Fault 1 Threshold */
24 TC654_REG_FAN_FAULT2 = 0x03, /* Fan Fault 2 Threshold */
25 TC654_REG_CONFIG = 0x04, /* Configuration */
26 TC654_REG_STATUS = 0x05, /* Status */
27 TC654_REG_DUTY_CYCLE = 0x06, /* Fan Speed Duty Cycle */
28 TC654_REG_MFR_ID = 0x07, /* Manufacturer Identification */
29 TC654_REG_VER_ID = 0x08, /* Version Identification */
30};
31
32/* Macros to easily index the registers */
33#define TC654_REG_RPM(idx) (TC654_REG_RPM1 + (idx))
34#define TC654_REG_FAN_FAULT(idx) (TC654_REG_FAN_FAULT1 + (idx))
35
36/* Config register bits */
37#define TC654_REG_CONFIG_RES BIT(6) /* Resolution Selection */
38#define TC654_REG_CONFIG_DUTYC BIT(5) /* Duty Cycle Control */
39#define TC654_REG_CONFIG_SDM BIT(0) /* Shutdown Mode */
40
41/* Status register bits */
42#define TC654_REG_STATUS_F2F BIT(1) /* Fan 2 Fault */
43#define TC654_REG_STATUS_F1F BIT(0) /* Fan 1 Fault */
44
45/* RPM resolution for RPM Output registers */
46#define TC654_HIGH_RPM_RESOLUTION 25 /* 25 RPM resolution */
47#define TC654_LOW_RPM_RESOLUTION 50 /* 50 RPM resolution */
48
49/* Convert to the fan fault RPM threshold from register value */
50#define TC654_FAN_FAULT_FROM_REG(val) ((val) * 50) /* 50 RPM resolution */
51
52/* Convert to register value from the fan fault RPM threshold */
53#define TC654_FAN_FAULT_TO_REG(val) (((val) / 50) & 0xff)
54
55/* Register data is read (and cached) at most once per second. */
56#define TC654_UPDATE_INTERVAL HZ
57
58struct tc654_data {
59 struct i2c_client *client;
60
61 /* update mutex */
62 struct mutex update_lock;
63
64 /* tc654 register cache */
65 bool valid;
66 unsigned long last_updated; /* in jiffies */
67
68 u8 rpm_output[2]; /* The fan RPM data for fans 1 and 2 is then
69 * written to registers RPM1 and RPM2
70 */
71 u8 fan_fault[2]; /* The Fan Fault Threshold Registers are used to
72 * set the fan fault threshold levels for fan 1
73 * and fan 2
74 */
75 u8 config; /* The Configuration Register is an 8-bit read/
76 * writable multi-function control register
77 * 7: Fan Fault Clear
78 * 1 = Clear Fan Fault
79 * 0 = Normal Operation (default)
80 * 6: Resolution Selection for RPM Output Registers
81 * RPM Output Registers (RPM1 and RPM2) will be
82 * set for
83 * 1 = 25 RPM (9-bit) resolution
84 * 0 = 50 RPM (8-bit) resolution (default)
85 * 5: Duty Cycle Control Method
86 * The V OUT duty cycle will be controlled via
87 * 1 = the SMBus interface.
88 * 0 = via the V IN analog input pin. (default)
89 * 4,3: Fan 2 Pulses Per Rotation
90 * 00 = 1
91 * 01 = 2 (default)
92 * 10 = 4
93 * 11 = 8
94 * 2,1: Fan 1 Pulses Per Rotation
95 * 00 = 1
96 * 01 = 2 (default)
97 * 10 = 4
98 * 11 = 8
99 * 0: Shutdown Mode
100 * 1 = Shutdown mode.
101 * 0 = Normal operation. (default)
102 */
103 u8 status; /* The Status register provides all the information
104 * about what is going on within the TC654/TC655
105 * devices.
106 * 7,6: Unimplemented, Read as '0'
107 * 5: Over-Temperature Fault Condition
108 * 1 = Over-Temperature condition has occurred
109 * 0 = Normal operation. V IN is less than 2.6V
110 * 4: RPM2 Counter Overflow
111 * 1 = Fault condition
112 * 0 = Normal operation
113 * 3: RPM1 Counter Overflow
114 * 1 = Fault condition
115 * 0 = Normal operation
116 * 2: V IN Input Status
117 * 1 = V IN is open
118 * 0 = Normal operation. voltage present at V IN
119 * 1: Fan 2 Fault
120 * 1 = Fault condition
121 * 0 = Normal operation
122 * 0: Fan 1 Fault
123 * 1 = Fault condition
124 * 0 = Normal operation
125 */
126 u8 duty_cycle; /* The DUTY_CYCLE register is a 4-bit read/
127 * writable register used to control the duty
128 * cycle of the V OUT output.
129 */
130};
131
132/* helper to grab and cache data, at most one time per second */
133static struct tc654_data *tc654_update_client(struct device *dev)
134{
135 struct tc654_data *data = dev_get_drvdata(dev);
136 struct i2c_client *client = data->client;
137 int ret = 0;
138
139 mutex_lock(&data->update_lock);
140 if (time_before(jiffies, data->last_updated + TC654_UPDATE_INTERVAL) &&
141 likely(data->valid))
142 goto out;
143
144 ret = i2c_smbus_read_byte_data(client, TC654_REG_RPM(0));
145 if (ret < 0)
146 goto out;
147 data->rpm_output[0] = ret;
148
149 ret = i2c_smbus_read_byte_data(client, TC654_REG_RPM(1));
150 if (ret < 0)
151 goto out;
152 data->rpm_output[1] = ret;
153
154 ret = i2c_smbus_read_byte_data(client, TC654_REG_FAN_FAULT(0));
155 if (ret < 0)
156 goto out;
157 data->fan_fault[0] = ret;
158
159 ret = i2c_smbus_read_byte_data(client, TC654_REG_FAN_FAULT(1));
160 if (ret < 0)
161 goto out;
162 data->fan_fault[1] = ret;
163
164 ret = i2c_smbus_read_byte_data(client, TC654_REG_CONFIG);
165 if (ret < 0)
166 goto out;
167 data->config = ret;
168
169 ret = i2c_smbus_read_byte_data(client, TC654_REG_STATUS);
170 if (ret < 0)
171 goto out;
172 data->status = ret;
173
174 ret = i2c_smbus_read_byte_data(client, TC654_REG_DUTY_CYCLE);
175 if (ret < 0)
176 goto out;
177 data->duty_cycle = ret & 0x0f;
178
179 data->last_updated = jiffies;
180 data->valid = true;
181out:
182 mutex_unlock(&data->update_lock);
183
184 if (ret < 0) /* upon error, encode it in return value */
185 data = ERR_PTR(ret);
186
187 return data;
188}
189
190/*
191 * sysfs attributes
192 */
193
194static ssize_t fan_show(struct device *dev, struct device_attribute *da,
195 char *buf)
196{
197 int nr = to_sensor_dev_attr(da)->index;
198 struct tc654_data *data = tc654_update_client(dev);
199 int val;
200
201 if (IS_ERR(data))
202 return PTR_ERR(data);
203
204 if (data->config & TC654_REG_CONFIG_RES)
205 val = data->rpm_output[nr] * TC654_HIGH_RPM_RESOLUTION;
206 else
207 val = data->rpm_output[nr] * TC654_LOW_RPM_RESOLUTION;
208
209 return sprintf(buf, "%d\n", val);
210}
211
212static ssize_t fan_min_show(struct device *dev, struct device_attribute *da,
213 char *buf)
214{
215 int nr = to_sensor_dev_attr(da)->index;
216 struct tc654_data *data = tc654_update_client(dev);
217
218 if (IS_ERR(data))
219 return PTR_ERR(data);
220
221 return sprintf(buf, "%d\n",
222 TC654_FAN_FAULT_FROM_REG(data->fan_fault[nr]));
223}
224
225static ssize_t fan_min_store(struct device *dev, struct device_attribute *da,
226 const char *buf, size_t count)
227{
228 int nr = to_sensor_dev_attr(da)->index;
229 struct tc654_data *data = dev_get_drvdata(dev);
230 struct i2c_client *client = data->client;
231 unsigned long val;
232 int ret;
233
234 if (kstrtoul(buf, 10, &val))
235 return -EINVAL;
236
237 val = clamp_val(val, 0, 12750);
238
239 mutex_lock(&data->update_lock);
240
241 data->fan_fault[nr] = TC654_FAN_FAULT_TO_REG(val);
242 ret = i2c_smbus_write_byte_data(client, TC654_REG_FAN_FAULT(nr),
243 data->fan_fault[nr]);
244
245 mutex_unlock(&data->update_lock);
246 return ret < 0 ? ret : count;
247}
248
249static ssize_t fan_alarm_show(struct device *dev, struct device_attribute *da,
250 char *buf)
251{
252 int nr = to_sensor_dev_attr(da)->index;
253 struct tc654_data *data = tc654_update_client(dev);
254 int val;
255
256 if (IS_ERR(data))
257 return PTR_ERR(data);
258
259 if (nr == 0)
260 val = !!(data->status & TC654_REG_STATUS_F1F);
261 else
262 val = !!(data->status & TC654_REG_STATUS_F2F);
263
264 return sprintf(buf, "%d\n", val);
265}
266
267static const u8 TC654_FAN_PULSE_SHIFT[] = { 1, 3 };
268
269static ssize_t fan_pulses_show(struct device *dev,
270 struct device_attribute *da, char *buf)
271{
272 int nr = to_sensor_dev_attr(da)->index;
273 struct tc654_data *data = tc654_update_client(dev);
274 u8 val;
275
276 if (IS_ERR(data))
277 return PTR_ERR(data);
278
279 val = BIT((data->config >> TC654_FAN_PULSE_SHIFT[nr]) & 0x03);
280 return sprintf(buf, "%d\n", val);
281}
282
283static ssize_t fan_pulses_store(struct device *dev,
284 struct device_attribute *da, const char *buf,
285 size_t count)
286{
287 int nr = to_sensor_dev_attr(da)->index;
288 struct tc654_data *data = dev_get_drvdata(dev);
289 struct i2c_client *client = data->client;
290 u8 config;
291 unsigned long val;
292 int ret;
293
294 if (kstrtoul(buf, 10, &val))
295 return -EINVAL;
296
297 switch (val) {
298 case 1:
299 config = 0;
300 break;
301 case 2:
302 config = 1;
303 break;
304 case 4:
305 config = 2;
306 break;
307 case 8:
308 config = 3;
309 break;
310 default:
311 return -EINVAL;
312 }
313
314 mutex_lock(&data->update_lock);
315
316 data->config &= ~(0x03 << TC654_FAN_PULSE_SHIFT[nr]);
317 data->config |= (config << TC654_FAN_PULSE_SHIFT[nr]);
318 ret = i2c_smbus_write_byte_data(client, TC654_REG_CONFIG, data->config);
319
320 mutex_unlock(&data->update_lock);
321 return ret < 0 ? ret : count;
322}
323
324static ssize_t pwm_mode_show(struct device *dev, struct device_attribute *da,
325 char *buf)
326{
327 struct tc654_data *data = tc654_update_client(dev);
328
329 if (IS_ERR(data))
330 return PTR_ERR(data);
331
332 return sprintf(buf, "%d\n", !!(data->config & TC654_REG_CONFIG_DUTYC));
333}
334
335static ssize_t pwm_mode_store(struct device *dev, struct device_attribute *da,
336 const char *buf, size_t count)
337{
338 struct tc654_data *data = dev_get_drvdata(dev);
339 struct i2c_client *client = data->client;
340 unsigned long val;
341 int ret;
342
343 if (kstrtoul(buf, 10, &val))
344 return -EINVAL;
345
346 if (val != 0 && val != 1)
347 return -EINVAL;
348
349 mutex_lock(&data->update_lock);
350
351 if (val)
352 data->config |= TC654_REG_CONFIG_DUTYC;
353 else
354 data->config &= ~TC654_REG_CONFIG_DUTYC;
355
356 ret = i2c_smbus_write_byte_data(client, TC654_REG_CONFIG, data->config);
357
358 mutex_unlock(&data->update_lock);
359 return ret < 0 ? ret : count;
360}
361
362static const int tc654_pwm_map[16] = { 77, 88, 102, 112, 124, 136, 148, 160,
363 172, 184, 196, 207, 219, 231, 243, 255};
364
365static ssize_t pwm_show(struct device *dev, struct device_attribute *da,
366 char *buf)
367{
368 struct tc654_data *data = tc654_update_client(dev);
369 int pwm;
370
371 if (IS_ERR(data))
372 return PTR_ERR(data);
373
374 if (data->config & TC654_REG_CONFIG_SDM)
375 pwm = 0;
376 else
377 pwm = tc654_pwm_map[data->duty_cycle];
378
379 return sprintf(buf, "%d\n", pwm);
380}
381
382static ssize_t pwm_store(struct device *dev, struct device_attribute *da,
383 const char *buf, size_t count)
384{
385 struct tc654_data *data = dev_get_drvdata(dev);
386 struct i2c_client *client = data->client;
387 unsigned long val;
388 int ret;
389
390 if (kstrtoul(buf, 10, &val))
391 return -EINVAL;
392 if (val > 255)
393 return -EINVAL;
394
395 mutex_lock(&data->update_lock);
396
397 if (val == 0)
398 data->config |= TC654_REG_CONFIG_SDM;
399 else
400 data->config &= ~TC654_REG_CONFIG_SDM;
401
402 data->duty_cycle = find_closest(val, tc654_pwm_map,
403 ARRAY_SIZE(tc654_pwm_map));
404
405 ret = i2c_smbus_write_byte_data(client, TC654_REG_CONFIG, data->config);
406 if (ret < 0)
407 goto out;
408
409 ret = i2c_smbus_write_byte_data(client, TC654_REG_DUTY_CYCLE,
410 data->duty_cycle);
411
412out:
413 mutex_unlock(&data->update_lock);
414 return ret < 0 ? ret : count;
415}
416
417static SENSOR_DEVICE_ATTR_RO(fan1_input, fan, 0);
418static SENSOR_DEVICE_ATTR_RO(fan2_input, fan, 1);
419static SENSOR_DEVICE_ATTR_RW(fan1_min, fan_min, 0);
420static SENSOR_DEVICE_ATTR_RW(fan2_min, fan_min, 1);
421static SENSOR_DEVICE_ATTR_RO(fan1_alarm, fan_alarm, 0);
422static SENSOR_DEVICE_ATTR_RO(fan2_alarm, fan_alarm, 1);
423static SENSOR_DEVICE_ATTR_RW(fan1_pulses, fan_pulses, 0);
424static SENSOR_DEVICE_ATTR_RW(fan2_pulses, fan_pulses, 1);
425static SENSOR_DEVICE_ATTR_RW(pwm1_mode, pwm_mode, 0);
426static SENSOR_DEVICE_ATTR_RW(pwm1, pwm, 0);
427
428/* Driver data */
429static struct attribute *tc654_attrs[] = {
430 &sensor_dev_attr_fan1_input.dev_attr.attr,
431 &sensor_dev_attr_fan2_input.dev_attr.attr,
432 &sensor_dev_attr_fan1_min.dev_attr.attr,
433 &sensor_dev_attr_fan2_min.dev_attr.attr,
434 &sensor_dev_attr_fan1_alarm.dev_attr.attr,
435 &sensor_dev_attr_fan2_alarm.dev_attr.attr,
436 &sensor_dev_attr_fan1_pulses.dev_attr.attr,
437 &sensor_dev_attr_fan2_pulses.dev_attr.attr,
438 &sensor_dev_attr_pwm1_mode.dev_attr.attr,
439 &sensor_dev_attr_pwm1.dev_attr.attr,
440 NULL
441};
442
443ATTRIBUTE_GROUPS(tc654);
444
445/*
446 * device probe and removal
447 */
448
449static int tc654_probe(struct i2c_client *client)
450{
451 struct device *dev = &client->dev;
452 struct tc654_data *data;
453 struct device *hwmon_dev;
454 int ret;
455
456 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
457 return -ENODEV;
458
459 data = devm_kzalloc(dev, sizeof(struct tc654_data), GFP_KERNEL);
460 if (!data)
461 return -ENOMEM;
462
463 data->client = client;
464 mutex_init(&data->update_lock);
465
466 ret = i2c_smbus_read_byte_data(client, TC654_REG_CONFIG);
467 if (ret < 0)
468 return ret;
469
470 data->config = ret;
471
472 hwmon_dev =
473 devm_hwmon_device_register_with_groups(dev, client->name, data,
474 tc654_groups);
475 return PTR_ERR_OR_ZERO(hwmon_dev);
476}
477
478static const struct i2c_device_id tc654_id[] = {
479 {"tc654", 0},
480 {"tc655", 0},
481 {}
482};
483
484MODULE_DEVICE_TABLE(i2c, tc654_id);
485
486static struct i2c_driver tc654_driver = {
487 .driver = {
488 .name = "tc654",
489 },
490 .probe_new = tc654_probe,
491 .id_table = tc654_id,
492};
493
494module_i2c_driver(tc654_driver);
495
496MODULE_AUTHOR("Allied Telesis Labs");
497MODULE_DESCRIPTION("Microchip TC654/TC655 driver");
498MODULE_LICENSE("GPL");