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