tmp102.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/* Texas Instruments TMP102 SMBus temperature sensor driver
  3 *
  4 * Copyright (C) 2010 Steven King <sfking@fdwdc.com>
  5 */
  6
  7#include <linux/delay.h>
  8#include <linux/module.h>
  9#include <linux/init.h>
 10#include <linux/slab.h>
 11#include <linux/i2c.h>
 12#include <linux/hwmon.h>
 13#include <linux/err.h>
 14#include <linux/device.h>
 15#include <linux/jiffies.h>
 16#include <linux/regmap.h>
 17#include <linux/regulator/consumer.h>
 18#include <linux/of.h>
 19
 20#define	DRIVER_NAME "tmp102"
 21
 22#define	TMP102_TEMP_REG			0x00
 23#define	TMP102_CONF_REG			0x01
 24/* note: these bit definitions are byte swapped */
 25#define		TMP102_CONF_SD		0x0100
 26#define		TMP102_CONF_TM		0x0200
 27#define		TMP102_CONF_POL		0x0400
 28#define		TMP102_CONF_F0		0x0800
 29#define		TMP102_CONF_F1		0x1000
 30#define		TMP102_CONF_R0		0x2000
 31#define		TMP102_CONF_R1		0x4000
 32#define		TMP102_CONF_OS		0x8000
 33#define		TMP102_CONF_EM		0x0010
 34#define		TMP102_CONF_AL		0x0020
 35#define		TMP102_CONF_CR0		0x0040
 36#define		TMP102_CONF_CR1		0x0080
 37#define	TMP102_TLOW_REG			0x02
 38#define	TMP102_THIGH_REG		0x03
 39
 40#define TMP102_CONFREG_MASK	(TMP102_CONF_SD | TMP102_CONF_TM | \
 41				 TMP102_CONF_POL | TMP102_CONF_F0 | \
 42				 TMP102_CONF_F1 | TMP102_CONF_OS | \
 43				 TMP102_CONF_EM | TMP102_CONF_AL | \
 44				 TMP102_CONF_CR0 | TMP102_CONF_CR1)
 45
 46#define TMP102_CONFIG_CLEAR	(TMP102_CONF_SD | TMP102_CONF_OS | \
 47				 TMP102_CONF_CR0)
 48#define TMP102_CONFIG_SET	(TMP102_CONF_TM | TMP102_CONF_EM | \
 49				 TMP102_CONF_CR1)
 50
 51#define CONVERSION_TIME_MS		35	/* in milli-seconds */
 52
 53struct tmp102 {
 54	const char *label;
 55	struct regmap *regmap;
 56	u16 config_orig;
 57	unsigned long ready_time;
 58};
 59
 60/* convert left adjusted 13-bit TMP102 register value to milliCelsius */
 61static inline int tmp102_reg_to_mC(s16 val)
 62{
 63	return ((val & ~0x01) * 1000) / 128;
 64}
 65
 66/* convert milliCelsius to left adjusted 13-bit TMP102 register value */
 67static inline u16 tmp102_mC_to_reg(int val)
 68{
 69	return (val * 128) / 1000;
 70}
 71
 72static int tmp102_read_string(struct device *dev, enum hwmon_sensor_types type,
 73			      u32 attr, int channel, const char **str)
 74{
 75	struct tmp102 *tmp102 = dev_get_drvdata(dev);
 76
 77	*str = tmp102->label;
 78
 79	return 0;
 80}
 81
 82static int tmp102_read(struct device *dev, enum hwmon_sensor_types type,
 83		       u32 attr, int channel, long *temp)
 84{
 85	struct tmp102 *tmp102 = dev_get_drvdata(dev);
 86	unsigned int regval;
 87	int err, reg;
 88
 89	switch (attr) {
 90	case hwmon_temp_input:
 91		/* Is it too early to return a conversion ? */
 92		if (time_before(jiffies, tmp102->ready_time)) {
 93			dev_dbg(dev, "%s: Conversion not ready yet..\n", __func__);
 94			return -EAGAIN;
 95		}
 96		reg = TMP102_TEMP_REG;
 97		break;
 98	case hwmon_temp_max_hyst:
 99		reg = TMP102_TLOW_REG;
100		break;
101	case hwmon_temp_max:
102		reg = TMP102_THIGH_REG;
103		break;
104	default:
105		return -EOPNOTSUPP;
106	}
107
108	err = regmap_read(tmp102->regmap, reg, &regval);
109	if (err < 0)
110		return err;
111	*temp = tmp102_reg_to_mC(regval);
112
113	return 0;
114}
115
116static int tmp102_write(struct device *dev, enum hwmon_sensor_types type,
117			u32 attr, int channel, long temp)
118{
119	struct tmp102 *tmp102 = dev_get_drvdata(dev);
120	int reg;
121
122	switch (attr) {
123	case hwmon_temp_max_hyst:
124		reg = TMP102_TLOW_REG;
125		break;
126	case hwmon_temp_max:
127		reg = TMP102_THIGH_REG;
128		break;
129	default:
130		return -EOPNOTSUPP;
131	}
132
133	temp = clamp_val(temp, -256000, 255000);
134	return regmap_write(tmp102->regmap, reg, tmp102_mC_to_reg(temp));
135}
136
137static umode_t tmp102_is_visible(const void *data, enum hwmon_sensor_types type,
138				 u32 attr, int channel)
139{
140	const struct tmp102 *tmp102 = data;
141
142	if (type != hwmon_temp)
143		return 0;
144
145	switch (attr) {
146	case hwmon_temp_input:
147		return 0444;
148	case hwmon_temp_label:
149		if (tmp102->label)
150			return 0444;
151		return 0;
152	case hwmon_temp_max_hyst:
153	case hwmon_temp_max:
154		return 0644;
155	default:
156		return 0;
157	}
158}
159
160static const struct hwmon_channel_info * const tmp102_info[] = {
161	HWMON_CHANNEL_INFO(chip,
162			   HWMON_C_REGISTER_TZ),
163	HWMON_CHANNEL_INFO(temp,
164			   HWMON_T_INPUT | HWMON_T_LABEL | HWMON_T_MAX | HWMON_T_MAX_HYST),
165	NULL
166};
167
168static const struct hwmon_ops tmp102_hwmon_ops = {
169	.is_visible = tmp102_is_visible,
170	.read_string = tmp102_read_string,
171	.read = tmp102_read,
172	.write = tmp102_write,
173};
174
175static const struct hwmon_chip_info tmp102_chip_info = {
176	.ops = &tmp102_hwmon_ops,
177	.info = tmp102_info,
178};
179
180static void tmp102_restore_config(void *data)
181{
182	struct tmp102 *tmp102 = data;
183
184	regmap_write(tmp102->regmap, TMP102_CONF_REG, tmp102->config_orig);
185}
186
187static bool tmp102_is_writeable_reg(struct device *dev, unsigned int reg)
188{
189	return reg != TMP102_TEMP_REG;
190}
191
192static bool tmp102_is_volatile_reg(struct device *dev, unsigned int reg)
193{
194	return reg == TMP102_TEMP_REG;
195}
196
197static const struct regmap_config tmp102_regmap_config = {
198	.reg_bits = 8,
199	.val_bits = 16,
200	.max_register = TMP102_THIGH_REG,
201	.writeable_reg = tmp102_is_writeable_reg,
202	.volatile_reg = tmp102_is_volatile_reg,
203	.val_format_endian = REGMAP_ENDIAN_BIG,
204	.cache_type = REGCACHE_MAPLE,
205	.use_single_read = true,
206	.use_single_write = true,
207};
208
209static int tmp102_probe(struct i2c_client *client)
210{
211	struct device *dev = &client->dev;
212	struct device *hwmon_dev;
213	struct tmp102 *tmp102;
214	unsigned int regval;
215	int err;
216
217	if (!i2c_check_functionality(client->adapter,
218				     I2C_FUNC_SMBUS_WORD_DATA)) {
219		dev_err(dev,
220			"adapter doesn't support SMBus word transactions\n");
221		return -ENODEV;
222	}
223
224	err = devm_regulator_get_enable_optional(dev, "vcc");
225	if (err < 0 && err != -ENODEV)
226		return dev_err_probe(dev, err, "Failed to enable regulator\n");
227
228	tmp102 = devm_kzalloc(dev, sizeof(*tmp102), GFP_KERNEL);
229	if (!tmp102)
230		return -ENOMEM;
231
232	of_property_read_string(dev->of_node, "label", &tmp102->label);
233
234	i2c_set_clientdata(client, tmp102);
235
236	tmp102->regmap = devm_regmap_init_i2c(client, &tmp102_regmap_config);
237	if (IS_ERR(tmp102->regmap))
238		return PTR_ERR(tmp102->regmap);
239
240	err = regmap_read(tmp102->regmap, TMP102_CONF_REG, &regval);
241	if (err < 0) {
242		dev_err(dev, "error reading config register\n");
243		return err;
244	}
245
246	if ((regval & ~TMP102_CONFREG_MASK) !=
247	    (TMP102_CONF_R0 | TMP102_CONF_R1)) {
248		dev_err(dev, "unexpected config register value\n");
249		return -ENODEV;
250	}
251
252	tmp102->config_orig = regval;
253
254	err = devm_add_action_or_reset(dev, tmp102_restore_config, tmp102);
255	if (err)
256		return err;
257
258	regval &= ~TMP102_CONFIG_CLEAR;
259	regval |= TMP102_CONFIG_SET;
260
261	err = regmap_write(tmp102->regmap, TMP102_CONF_REG, regval);
262	if (err < 0) {
263		dev_err(dev, "error writing config register\n");
264		return err;
265	}
266
267	/*
268	 * Mark that we are not ready with data until the first
269	 * conversion is complete
270	 */
271	tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS);
272
273	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
274							 tmp102,
275							 &tmp102_chip_info,
276							 NULL);
277	if (IS_ERR(hwmon_dev)) {
278		dev_dbg(dev, "unable to register hwmon device\n");
279		return PTR_ERR(hwmon_dev);
280	}
281	dev_info(dev, "initialized\n");
282
283	return 0;
284}
285
286static int tmp102_suspend(struct device *dev)
287{
288	struct i2c_client *client = to_i2c_client(dev);
289	struct tmp102 *tmp102 = i2c_get_clientdata(client);
290
291	return regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
292				  TMP102_CONF_SD, TMP102_CONF_SD);
293}
294
295static int tmp102_resume(struct device *dev)
296{
297	struct i2c_client *client = to_i2c_client(dev);
298	struct tmp102 *tmp102 = i2c_get_clientdata(client);
299	int err;
300
301	err = regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
302				 TMP102_CONF_SD, 0);
303
304	tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS);
305
306	return err;
307}
308
309static DEFINE_SIMPLE_DEV_PM_OPS(tmp102_dev_pm_ops, tmp102_suspend, tmp102_resume);
310
311static const struct i2c_device_id tmp102_id[] = {
312	{ "tmp102" },
313	{ }
314};
315MODULE_DEVICE_TABLE(i2c, tmp102_id);
316
317static const struct of_device_id __maybe_unused tmp102_of_match[] = {
318	{ .compatible = "ti,tmp102" },
319	{ },
320};
321MODULE_DEVICE_TABLE(of, tmp102_of_match);
322
323static struct i2c_driver tmp102_driver = {
324	.driver.name	= DRIVER_NAME,
325	.driver.of_match_table = of_match_ptr(tmp102_of_match),
326	.driver.pm	= pm_sleep_ptr(&tmp102_dev_pm_ops),
327	.probe		= tmp102_probe,
328	.id_table	= tmp102_id,
329};
330
331module_i2c_driver(tmp102_driver);
332
333MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
334MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
335MODULE_LICENSE("GPL");