max6620.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Hardware monitoring driver for Maxim MAX6620
  4 *
  5 * Originally from L. Grunenberg.
  6 * (C) 2012 by L. Grunenberg <contact@lgrunenberg.de>
  7 *
  8 * Copyright (c) 2021 Dell Inc. or its subsidiaries. All Rights Reserved.
  9 *
 10 * based on code written by :
 11 * 2007 by Hans J. Koch <hjk@hansjkoch.de>
 12 * John Morris <john.morris@spirentcom.com>
 13 * Copyright (c) 2003 Spirent Communications
 14 * and Claus Gindhart <claus.gindhart@kontron.com>
 15 *
 16 * This module has only been tested with the MAX6620 chip.
 17 *
 18 * The datasheet was last seen at:
 19 *
 20 *        http://pdfserv.maxim-ic.com/en/ds/MAX6620.pdf
 21 *
 22 */
 23
 24#include <linux/bits.h>
 25#include <linux/err.h>
 26#include <linux/hwmon.h>
 27#include <linux/i2c.h>
 28#include <linux/init.h>
 29#include <linux/jiffies.h>
 30#include <linux/module.h>
 31#include <linux/slab.h>
 32
 33/*
 34 * MAX 6620 registers
 35 */
 36
 37#define MAX6620_REG_CONFIG	0x00
 38#define MAX6620_REG_FAULT	0x01
 39#define MAX6620_REG_CONF_FAN0	0x02
 40#define MAX6620_REG_CONF_FAN1	0x03
 41#define MAX6620_REG_CONF_FAN2	0x04
 42#define MAX6620_REG_CONF_FAN3	0x05
 43#define MAX6620_REG_DYN_FAN0	0x06
 44#define MAX6620_REG_DYN_FAN1	0x07
 45#define MAX6620_REG_DYN_FAN2	0x08
 46#define MAX6620_REG_DYN_FAN3	0x09
 47#define MAX6620_REG_TACH0	0x10
 48#define MAX6620_REG_TACH1	0x12
 49#define MAX6620_REG_TACH2	0x14
 50#define MAX6620_REG_TACH3	0x16
 51#define MAX6620_REG_VOLT0	0x18
 52#define MAX6620_REG_VOLT1	0x1A
 53#define MAX6620_REG_VOLT2	0x1C
 54#define MAX6620_REG_VOLT3	0x1E
 55#define MAX6620_REG_TAR0	0x20
 56#define MAX6620_REG_TAR1	0x22
 57#define MAX6620_REG_TAR2	0x24
 58#define MAX6620_REG_TAR3	0x26
 59#define MAX6620_REG_DAC0	0x28
 60#define MAX6620_REG_DAC1	0x2A
 61#define MAX6620_REG_DAC2	0x2C
 62#define MAX6620_REG_DAC3	0x2E
 63
 64/*
 65 * Config register bits
 66 */
 67
 68#define MAX6620_CFG_RUN		BIT(7)
 69#define MAX6620_CFG_POR		BIT(6)
 70#define MAX6620_CFG_TIMEOUT	BIT(5)
 71#define MAX6620_CFG_FULLFAN	BIT(4)
 72#define MAX6620_CFG_OSC		BIT(3)
 73#define MAX6620_CFG_WD_MASK	(BIT(2) | BIT(1))
 74#define MAX6620_CFG_WD_2	BIT(1)
 75#define MAX6620_CFG_WD_6	BIT(2)
 76#define MAX6620_CFG_WD10	(BIT(2) | BIT(1))
 77#define MAX6620_CFG_WD		BIT(0)
 78
 79/*
 80 * Failure status register bits
 81 */
 82
 83#define MAX6620_FAIL_TACH0	BIT(4)
 84#define MAX6620_FAIL_TACH1	BIT(5)
 85#define MAX6620_FAIL_TACH2	BIT(6)
 86#define MAX6620_FAIL_TACH3	BIT(7)
 87#define MAX6620_FAIL_MASK0	BIT(0)
 88#define MAX6620_FAIL_MASK1	BIT(1)
 89#define MAX6620_FAIL_MASK2	BIT(2)
 90#define MAX6620_FAIL_MASK3	BIT(3)
 91
 92#define MAX6620_CLOCK_FREQ	8192 /* Clock frequency in Hz */
 93#define MAX6620_PULSE_PER_REV	2 /* Tachometer pulses per revolution */
 94
 95/* Minimum and maximum values of the FAN-RPM */
 96#define FAN_RPM_MIN	240
 97#define FAN_RPM_MAX	30000
 98
 99static const u8 config_reg[] = {
100	MAX6620_REG_CONF_FAN0,
101	MAX6620_REG_CONF_FAN1,
102	MAX6620_REG_CONF_FAN2,
103	MAX6620_REG_CONF_FAN3,
104};
105
106static const u8 dyn_reg[] = {
107	MAX6620_REG_DYN_FAN0,
108	MAX6620_REG_DYN_FAN1,
109	MAX6620_REG_DYN_FAN2,
110	MAX6620_REG_DYN_FAN3,
111};
112
113static const u8 tach_reg[] = {
114	MAX6620_REG_TACH0,
115	MAX6620_REG_TACH1,
116	MAX6620_REG_TACH2,
117	MAX6620_REG_TACH3,
118};
119
120static const u8 target_reg[] = {
121	MAX6620_REG_TAR0,
122	MAX6620_REG_TAR1,
123	MAX6620_REG_TAR2,
124	MAX6620_REG_TAR3,
125};
126
127/*
128 * Client data (each client gets its own)
129 */
130
131struct max6620_data {
132	struct i2c_client *client;
133	bool valid; /* false until following fields are valid */
134	unsigned long last_updated; /* in jiffies */
135
136	/* register values */
137	u8 fancfg[4];
138	u8 fandyn[4];
139	u8 fault;
140	u16 tach[4];
141	u16 target[4];
142};
143
144static u8 max6620_fan_div_from_reg(u8 val)
145{
146	return BIT((val & 0xE0) >> 5);
147}
148
149static u16 max6620_fan_rpm_to_tach(u8 div, int rpm)
150{
151	return (60 * div * MAX6620_CLOCK_FREQ) / (rpm * MAX6620_PULSE_PER_REV);
152}
153
154static int max6620_fan_tach_to_rpm(u8 div, u16 tach)
155{
156	return (60 * div * MAX6620_CLOCK_FREQ) / (tach * MAX6620_PULSE_PER_REV);
157}
158
159static int max6620_update_device(struct device *dev)
160{
161	struct max6620_data *data = dev_get_drvdata(dev);
162	struct i2c_client *client = data->client;
163	int i, ret;
164
165	if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
166		for (i = 0; i < 4; i++) {
167			ret = i2c_smbus_read_byte_data(client, config_reg[i]);
168			if (ret < 0)
169				return ret;
170			data->fancfg[i] = ret;
171
172			ret = i2c_smbus_read_byte_data(client, dyn_reg[i]);
173			if (ret < 0)
174				return ret;
175			data->fandyn[i] = ret;
176
177			ret = i2c_smbus_read_byte_data(client, tach_reg[i]);
178			if (ret < 0)
179				return ret;
180			data->tach[i] = (ret << 3) & 0x7f8;
181			ret = i2c_smbus_read_byte_data(client, tach_reg[i] + 1);
182			if (ret < 0)
183				return ret;
184			data->tach[i] |= (ret >> 5) & 0x7;
185
186			ret = i2c_smbus_read_byte_data(client, target_reg[i]);
187			if (ret < 0)
188				return ret;
189			data->target[i] = (ret << 3) & 0x7f8;
190			ret = i2c_smbus_read_byte_data(client, target_reg[i] + 1);
191			if (ret < 0)
192				return ret;
193			data->target[i] |= (ret >> 5) & 0x7;
194		}
195
196		/*
197		 * Alarms are cleared on read in case the condition that
198		 * caused the alarm is removed. Keep the value latched here
199		 * for providing the register through different alarm files.
200		 */
201		ret = i2c_smbus_read_byte_data(client, MAX6620_REG_FAULT);
202		if (ret < 0)
203			return ret;
204		data->fault |= (ret >> 4) & (ret & 0x0F);
205
206		data->last_updated = jiffies;
207		data->valid = true;
208	}
209	return 0;
210}
211
212static umode_t
213max6620_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr,
214		   int channel)
215{
216	switch (type) {
217	case hwmon_fan:
218		switch (attr) {
219		case hwmon_fan_alarm:
220		case hwmon_fan_input:
221			return 0444;
222		case hwmon_fan_div:
223		case hwmon_fan_target:
224			return 0644;
225		default:
226			break;
227		}
228		break;
229	default:
230		break;
231	}
232
233	return 0;
234}
235
236static int
237max6620_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
238	     int channel, long *val)
239{
240	struct max6620_data *data;
241	struct i2c_client *client;
242	int ret;
243	u8 div;
244	u8 val1;
245	u8 val2;
246
247	ret = max6620_update_device(dev);
248	if (ret < 0)
249		return ret;
250	data = dev_get_drvdata(dev);
251	client = data->client;
252
253	switch (type) {
254	case hwmon_fan:
255		switch (attr) {
256		case hwmon_fan_alarm:
257			*val = !!(data->fault & BIT(channel));
258
259			/* Setting TACH count to re-enable fan fault detection */
260			if (*val == 1) {
261				val1 = (data->target[channel] >> 3) & 0xff;
262				val2 = (data->target[channel] << 5) & 0xe0;
263				ret = i2c_smbus_write_byte_data(client,
264								target_reg[channel], val1);
265				if (ret < 0)
266					return ret;
267				ret = i2c_smbus_write_byte_data(client,
268								target_reg[channel] + 1, val2);
269				if (ret < 0)
270					return ret;
271
272				data->fault &= ~BIT(channel);
273			}
274			break;
275		case hwmon_fan_div:
276			*val = max6620_fan_div_from_reg(data->fandyn[channel]);
277			break;
278		case hwmon_fan_input:
279			if (data->tach[channel] == 0) {
280				*val = 0;
281			} else {
282				div = max6620_fan_div_from_reg(data->fandyn[channel]);
283				*val = max6620_fan_tach_to_rpm(div, data->tach[channel]);
284			}
285			break;
286		case hwmon_fan_target:
287			if (data->target[channel] == 0) {
288				*val = 0;
289			} else {
290				div = max6620_fan_div_from_reg(data->fandyn[channel]);
291				*val = max6620_fan_tach_to_rpm(div, data->target[channel]);
292			}
293			break;
294		default:
295			return -EOPNOTSUPP;
296		}
297		break;
298
299	default:
300		return -EOPNOTSUPP;
301	}
302
303	return 0;
304}
305
306static int
307max6620_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
308	      int channel, long val)
309{
310	struct max6620_data *data;
311	struct i2c_client *client;
312	int ret;
313	u8 div;
314	u16 tach;
315	u8 val1;
316	u8 val2;
317
318	ret = max6620_update_device(dev);
319	if (ret < 0)
320		return ret;
321	data = dev_get_drvdata(dev);
322	client = data->client;
323
324	switch (type) {
325	case hwmon_fan:
326		switch (attr) {
327		case hwmon_fan_div:
328			switch (val) {
329			case 1:
330				div = 0;
331				break;
332			case 2:
333				div = 1;
334				break;
335			case 4:
336				div = 2;
337				break;
338			case 8:
339				div = 3;
340				break;
341			case 16:
342				div = 4;
343				break;
344			case 32:
345				div = 5;
346				break;
347			default:
348				return -EINVAL;
349			}
350			data->fandyn[channel] &= 0x1F;
351			data->fandyn[channel] |= div << 5;
352			ret = i2c_smbus_write_byte_data(client, dyn_reg[channel],
353							data->fandyn[channel]);
354			break;
355		case hwmon_fan_target:
356			val = clamp_val(val, FAN_RPM_MIN, FAN_RPM_MAX);
357			div = max6620_fan_div_from_reg(data->fandyn[channel]);
358			tach = max6620_fan_rpm_to_tach(div, val);
359			val1 = (tach >> 3) & 0xff;
360			val2 = (tach << 5) & 0xe0;
361			ret = i2c_smbus_write_byte_data(client, target_reg[channel], val1);
362			if (ret < 0)
363				break;
364			ret = i2c_smbus_write_byte_data(client, target_reg[channel] + 1, val2);
365			if (ret < 0)
366				break;
367
368			/* Setting TACH count re-enables fan fault detection */
369			data->fault &= ~BIT(channel);
370
371			break;
372		default:
373			ret = -EOPNOTSUPP;
374			break;
375		}
376		break;
377
378	default:
379		ret = -EOPNOTSUPP;
380		break;
381	}
382
383	return ret;
384}
385
386static const struct hwmon_channel_info * const max6620_info[] = {
387	HWMON_CHANNEL_INFO(fan,
388			   HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM,
389			   HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM,
390			   HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM,
391			   HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM),
392	NULL
393};
394
395static const struct hwmon_ops max6620_hwmon_ops = {
396	.read = max6620_read,
397	.write = max6620_write,
398	.is_visible = max6620_is_visible,
399};
400
401static const struct hwmon_chip_info max6620_chip_info = {
402	.ops = &max6620_hwmon_ops,
403	.info = max6620_info,
404};
405
406static int max6620_init_client(struct max6620_data *data)
407{
408	struct i2c_client *client = data->client;
409	int config;
410	int err;
411	int i;
412	int reg;
413
414	config = i2c_smbus_read_byte_data(client, MAX6620_REG_CONFIG);
415	if (config < 0) {
416		dev_err(&client->dev, "Error reading config, aborting.\n");
417		return config;
418	}
419
420	/*
421	 * Set bit 4, disable other fans from going full speed on a fail
422	 * failure.
423	 */
424	err = i2c_smbus_write_byte_data(client, MAX6620_REG_CONFIG, config | 0x10);
425	if (err < 0) {
426		dev_err(&client->dev, "Config write error, aborting.\n");
427		return err;
428	}
429
430	for (i = 0; i < 4; i++) {
431		reg = i2c_smbus_read_byte_data(client, config_reg[i]);
432		if (reg < 0)
433			return reg;
434		data->fancfg[i] = reg;
435
436		/* Enable RPM mode */
437		data->fancfg[i] |= 0xa8;
438		err = i2c_smbus_write_byte_data(client, config_reg[i], data->fancfg[i]);
439		if (err < 0)
440			return err;
441
442		/* 2 counts (001) and Rate change 100 (0.125 secs) */
443		data->fandyn[i] = 0x30;
444		err = i2c_smbus_write_byte_data(client, dyn_reg[i], data->fandyn[i]);
445		if (err < 0)
446			return err;
447	}
448	return 0;
449}
450
451static int max6620_probe(struct i2c_client *client)
452{
453	struct device *dev = &client->dev;
454	struct max6620_data *data;
455	struct device *hwmon_dev;
456	int err;
457
458	data = devm_kzalloc(dev, sizeof(struct max6620_data), GFP_KERNEL);
459	if (!data)
460		return -ENOMEM;
461
462	data->client = client;
463
464	err = max6620_init_client(data);
465	if (err)
466		return err;
467
468	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
469							 data,
470							 &max6620_chip_info,
471							 NULL);
472
473	return PTR_ERR_OR_ZERO(hwmon_dev);
474}
475
476static const struct i2c_device_id max6620_id[] = {
477	{ "max6620" },
478	{ }
479};
480MODULE_DEVICE_TABLE(i2c, max6620_id);
481
482static struct i2c_driver max6620_driver = {
483	.class		= I2C_CLASS_HWMON,
484	.driver = {
485		.name	= "max6620",
486	},
487	.probe		= max6620_probe,
488	.id_table	= max6620_id,
489};
490
491module_i2c_driver(max6620_driver);
492
493MODULE_AUTHOR("Lucas Grunenberg");
494MODULE_DESCRIPTION("MAX6620 sensor driver");
495MODULE_LICENSE("GPL");