tmp421.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/* tmp421.c
  3 *
  4 * Copyright (C) 2009 Andre Prendel <andre.prendel@gmx.de>
  5 * Preliminary support by:
  6 * Melvin Rook, Raymond Ng
  7 */
  8
  9/*
 10 * Driver for the Texas Instruments TMP421 SMBus temperature sensor IC.
 11 * Supported models: TMP421, TMP422, TMP423, TMP441, TMP442
 12 */
 13
 14#include <linux/module.h>
 15#include <linux/init.h>
 16#include <linux/slab.h>
 17#include <linux/jiffies.h>
 18#include <linux/i2c.h>
 19#include <linux/hwmon.h>
 20#include <linux/hwmon-sysfs.h>
 21#include <linux/err.h>
 22#include <linux/of.h>
 23#include <linux/sysfs.h>
 24
 25/* Addresses to scan */
 26static const unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f,
 27					     I2C_CLIENT_END };
 28
 29enum chips { tmp421, tmp422, tmp423, tmp441, tmp442 };
 30
 31#define MAX_CHANNELS				4
 32/* The TMP421 registers */
 33#define TMP421_STATUS_REG			0x08
 34#define TMP421_CONFIG_REG_1			0x09
 35#define TMP421_CONFIG_REG_2			0x0A
 36#define TMP421_CONFIG_REG_REN(x)		(BIT(3 + (x)))
 37#define TMP421_CONFIG_REG_REN_MASK		GENMASK(6, 3)
 38#define TMP421_CONVERSION_RATE_REG		0x0B
 39#define TMP421_N_FACTOR_REG_1			0x21
 40#define TMP421_MANUFACTURER_ID_REG		0xFE
 41#define TMP421_DEVICE_ID_REG			0xFF
 42
 43static const u8 TMP421_TEMP_MSB[MAX_CHANNELS]	= { 0x00, 0x01, 0x02, 0x03 };
 44static const u8 TMP421_TEMP_LSB[MAX_CHANNELS]	= { 0x10, 0x11, 0x12, 0x13 };
 45
 46/* Flags */
 47#define TMP421_CONFIG_SHUTDOWN			0x40
 48#define TMP421_CONFIG_RANGE			0x04
 49
 50/* Manufacturer / Device ID's */
 51#define TMP421_MANUFACTURER_ID			0x55
 52#define TMP421_DEVICE_ID			0x21
 53#define TMP422_DEVICE_ID			0x22
 54#define TMP423_DEVICE_ID			0x23
 55#define TMP441_DEVICE_ID			0x41
 56#define TMP442_DEVICE_ID			0x42
 57
 58static const struct i2c_device_id tmp421_id[] = {
 59	{ "tmp421", 2 },
 60	{ "tmp422", 3 },
 61	{ "tmp423", 4 },
 62	{ "tmp441", 2 },
 63	{ "tmp442", 3 },
 64	{ }
 65};
 66MODULE_DEVICE_TABLE(i2c, tmp421_id);
 67
 68static const struct of_device_id __maybe_unused tmp421_of_match[] = {
 69	{
 70		.compatible = "ti,tmp421",
 71		.data = (void *)2
 72	},
 73	{
 74		.compatible = "ti,tmp422",
 75		.data = (void *)3
 76	},
 77	{
 78		.compatible = "ti,tmp423",
 79		.data = (void *)4
 80	},
 81	{
 82		.compatible = "ti,tmp441",
 83		.data = (void *)2
 84	},
 85	{
 86		.compatible = "ti,tmp442",
 87		.data = (void *)3
 88	},
 89	{ },
 90};
 91MODULE_DEVICE_TABLE(of, tmp421_of_match);
 92
 93struct tmp421_channel {
 94	const char *label;
 95	bool enabled;
 96	s16 temp;
 97};
 98
 99struct tmp421_data {
100	struct i2c_client *client;
101	u32 temp_config[MAX_CHANNELS + 1];
102	struct hwmon_channel_info temp_info;
103	const struct hwmon_channel_info *info[2];
104	struct hwmon_chip_info chip;
105	bool valid;
106	unsigned long last_updated;
107	unsigned long channels;
108	u8 config;
109	struct tmp421_channel channel[MAX_CHANNELS];
110};
111
112static int temp_from_raw(u16 reg, bool extended)
113{
114	/* Mask out status bits */
115	int temp = reg & ~0xf;
116
117	if (extended)
118		temp = temp - 64 * 256;
119	else
120		temp = (s16)temp;
121
122	return DIV_ROUND_CLOSEST(temp * 1000, 256);
123}
124
125static int tmp421_update_device(struct tmp421_data *data)
126{
127	struct i2c_client *client = data->client;
128	int ret = 0;
129	int i;
130
131	if (time_after(jiffies, data->last_updated + (HZ / 2)) ||
132	    !data->valid) {
133		data->valid = false;
134		ret = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
135		if (ret < 0)
136			return ret;
137		data->config = ret;
138
139		for (i = 0; i < data->channels; i++) {
140			ret = i2c_smbus_read_byte_data(client, TMP421_TEMP_MSB[i]);
141			if (ret < 0)
142				return ret;
143			data->channel[i].temp = ret << 8;
144
145			ret = i2c_smbus_read_byte_data(client, TMP421_TEMP_LSB[i]);
146			if (ret < 0)
147				return ret;
148			data->channel[i].temp |= ret;
149		}
150		data->last_updated = jiffies;
151		data->valid = true;
152	}
153	return 0;
154}
155
156static int tmp421_enable_channels(struct tmp421_data *data)
157{
158	int err;
159	struct i2c_client *client = data->client;
160	struct device *dev = &client->dev;
161	int old = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_2);
162	int new, i;
163
164	if (old < 0) {
165		dev_err(dev, "error reading register, can't disable channels\n");
166		return old;
167	}
168
169	new = old & ~TMP421_CONFIG_REG_REN_MASK;
170	for (i = 0; i < data->channels; i++)
171		if (data->channel[i].enabled)
172			new |= TMP421_CONFIG_REG_REN(i);
173
174	if (new == old)
175		return 0;
176
177	err = i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_2, new);
178	if (err < 0)
179		dev_err(dev, "error writing register, can't disable channels\n");
180
181	return err;
182}
183
184static int tmp421_read(struct device *dev, enum hwmon_sensor_types type,
185		       u32 attr, int channel, long *val)
186{
187	struct tmp421_data *tmp421 = dev_get_drvdata(dev);
188	int ret = 0;
189
190	ret = tmp421_update_device(tmp421);
191	if (ret)
192		return ret;
193
194	switch (attr) {
195	case hwmon_temp_input:
196		if (!tmp421->channel[channel].enabled)
197			return -ENODATA;
198		*val = temp_from_raw(tmp421->channel[channel].temp,
199				     tmp421->config & TMP421_CONFIG_RANGE);
200		return 0;
201	case hwmon_temp_fault:
202		if (!tmp421->channel[channel].enabled)
203			return -ENODATA;
204		/*
205		 * Any of OPEN or /PVLD bits indicate a hardware mulfunction
206		 * and the conversion result may be incorrect
207		 */
208		*val = !!(tmp421->channel[channel].temp & 0x03);
209		return 0;
210	case hwmon_temp_enable:
211		*val = tmp421->channel[channel].enabled;
212		return 0;
213	default:
214		return -EOPNOTSUPP;
215	}
216
217}
218
219static int tmp421_read_string(struct device *dev, enum hwmon_sensor_types type,
220			     u32 attr, int channel, const char **str)
221{
222	struct tmp421_data *data = dev_get_drvdata(dev);
223
224	*str = data->channel[channel].label;
225
226	return 0;
227}
228
229static int tmp421_write(struct device *dev, enum hwmon_sensor_types type,
230			u32 attr, int channel, long val)
231{
232	struct tmp421_data *data = dev_get_drvdata(dev);
233	int ret;
234
235	switch (attr) {
236	case hwmon_temp_enable:
237		data->channel[channel].enabled = val;
238		ret = tmp421_enable_channels(data);
239		break;
240	default:
241	    ret = -EOPNOTSUPP;
242	}
243
244	return ret;
245}
246
247static umode_t tmp421_is_visible(const void *data, enum hwmon_sensor_types type,
248				 u32 attr, int channel)
249{
250	switch (attr) {
251	case hwmon_temp_fault:
252	case hwmon_temp_input:
253	case hwmon_temp_label:
254		return 0444;
255	case hwmon_temp_enable:
256		return 0644;
257	default:
258		return 0;
259	}
260}
261
262static int tmp421_init_client(struct tmp421_data *data)
263{
264	int config, config_orig;
265	struct i2c_client *client = data->client;
266
267	/* Set the conversion rate to 2 Hz */
268	i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);
269
270	/* Start conversions (disable shutdown if necessary) */
271	config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
272	if (config < 0) {
273		dev_err(&client->dev,
274			"Could not read configuration register (%d)\n", config);
275		return config;
276	}
277
278	config_orig = config;
279	config &= ~TMP421_CONFIG_SHUTDOWN;
280
281	if (config != config_orig) {
282		dev_info(&client->dev, "Enable monitoring chip\n");
283		i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
284	}
285
286	return tmp421_enable_channels(data);
287}
288
289static int tmp421_detect(struct i2c_client *client,
290			 struct i2c_board_info *info)
291{
292	enum chips kind;
293	struct i2c_adapter *adapter = client->adapter;
294	static const char * const names[] = {
295		"TMP421", "TMP422", "TMP423",
296		"TMP441", "TMP442"
297	};
298	int addr = client->addr;
299	u8 reg;
300
301	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
302		return -ENODEV;
303
304	reg = i2c_smbus_read_byte_data(client, TMP421_MANUFACTURER_ID_REG);
305	if (reg != TMP421_MANUFACTURER_ID)
306		return -ENODEV;
307
308	reg = i2c_smbus_read_byte_data(client, TMP421_CONVERSION_RATE_REG);
309	if (reg & 0xf8)
310		return -ENODEV;
311
312	reg = i2c_smbus_read_byte_data(client, TMP421_STATUS_REG);
313	if (reg & 0x7f)
314		return -ENODEV;
315
316	reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG);
317	switch (reg) {
318	case TMP421_DEVICE_ID:
319		kind = tmp421;
320		break;
321	case TMP422_DEVICE_ID:
322		if (addr == 0x2a)
323			return -ENODEV;
324		kind = tmp422;
325		break;
326	case TMP423_DEVICE_ID:
327		if (addr != 0x4c && addr != 0x4d)
328			return -ENODEV;
329		kind = tmp423;
330		break;
331	case TMP441_DEVICE_ID:
332		kind = tmp441;
333		break;
334	case TMP442_DEVICE_ID:
335		if (addr != 0x4c && addr != 0x4d)
336			return -ENODEV;
337		kind = tmp442;
338		break;
339	default:
340		return -ENODEV;
341	}
342
343	strscpy(info->type, tmp421_id[kind].name, I2C_NAME_SIZE);
344	dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n",
345		 names[kind], client->addr);
346
347	return 0;
348}
349
350static int tmp421_probe_child_from_dt(struct i2c_client *client,
351				      struct device_node *child,
352				      struct tmp421_data *data)
353
354{
355	struct device *dev = &client->dev;
356	u32 i;
357	s32 val;
358	int err;
359
360	err = of_property_read_u32(child, "reg", &i);
361	if (err) {
362		dev_err(dev, "missing reg property of %pOFn\n", child);
363		return err;
364	}
365
366	if (i >= data->channels) {
367		dev_err(dev, "invalid reg %d of %pOFn\n", i, child);
368		return -EINVAL;
369	}
370
371	err = of_property_read_string(child, "label", &data->channel[i].label);
372	if (err == -ENODATA || err == -EILSEQ) {
373		dev_err(dev, "invalid label property in %pOFn\n", child);
374		return err;
375	}
376	if (data->channel[i].label)
377		data->temp_config[i] |= HWMON_T_LABEL;
378
379	data->channel[i].enabled = of_device_is_available(child);
380
381	err = of_property_read_s32(child, "ti,n-factor", &val);
382	if (!err) {
383		if (i == 0) {
384			dev_err(dev, "n-factor can't be set for internal channel\n");
385			return -EINVAL;
386		}
387
388		if (val > 127 || val < -128) {
389			dev_err(dev, "n-factor for channel %d invalid (%d)\n",
390				i, val);
391			return -EINVAL;
392		}
393		i2c_smbus_write_byte_data(client, TMP421_N_FACTOR_REG_1 + i - 1,
394					  val);
395	}
396
397	return 0;
398}
399
400static int tmp421_probe_from_dt(struct i2c_client *client, struct tmp421_data *data)
401{
402	struct device *dev = &client->dev;
403	const struct device_node *np = dev->of_node;
404	int err;
405
406	for_each_child_of_node_scoped(np, child) {
407		if (strcmp(child->name, "channel"))
408			continue;
409
410		err = tmp421_probe_child_from_dt(client, child, data);
411		if (err)
412			return err;
413	}
414
415	return 0;
416}
417
418static const struct hwmon_ops tmp421_ops = {
419	.is_visible = tmp421_is_visible,
420	.read = tmp421_read,
421	.read_string = tmp421_read_string,
422	.write = tmp421_write,
423};
424
425static int tmp421_probe(struct i2c_client *client)
426{
427	struct device *dev = &client->dev;
428	struct device *hwmon_dev;
429	struct tmp421_data *data;
430	int i, err;
431
432	data = devm_kzalloc(dev, sizeof(struct tmp421_data), GFP_KERNEL);
433	if (!data)
434		return -ENOMEM;
435
436	data->channels = (unsigned long)i2c_get_match_data(client);
437	data->client = client;
438
439	for (i = 0; i < data->channels; i++) {
440		data->temp_config[i] = HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_ENABLE;
441		data->channel[i].enabled = true;
442	}
443
444	err = tmp421_probe_from_dt(client, data);
445	if (err)
446		return err;
447
448	err = tmp421_init_client(data);
449	if (err)
450		return err;
451
452	data->chip.ops = &tmp421_ops;
453	data->chip.info = data->info;
454
455	data->info[0] = &data->temp_info;
456
457	data->temp_info.type = hwmon_temp;
458	data->temp_info.config = data->temp_config;
459
460	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
461							 data,
462							 &data->chip,
463							 NULL);
464	return PTR_ERR_OR_ZERO(hwmon_dev);
465}
466
467static struct i2c_driver tmp421_driver = {
468	.class = I2C_CLASS_HWMON,
469	.driver = {
470		.name	= "tmp421",
471		.of_match_table = of_match_ptr(tmp421_of_match),
472	},
473	.probe = tmp421_probe,
474	.id_table = tmp421_id,
475	.detect = tmp421_detect,
476	.address_list = normal_i2c,
477};
478
479module_i2c_driver(tmp421_driver);
480
481MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>");
482MODULE_DESCRIPTION("Texas Instruments TMP421/422/423/441/442 temperature sensor driver");
483MODULE_LICENSE("GPL");