xref: /openbmc/linux/drivers/hwmon/tmp102.c (revision 6de298ff) 
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/of.h>
20 
21 #define	DRIVER_NAME "tmp102"
22 
23 #define	TMP102_TEMP_REG			0x00
24 #define	TMP102_CONF_REG			0x01
25 /* note: these bit definitions are byte swapped */
26 #define		TMP102_CONF_SD		0x0100
27 #define		TMP102_CONF_TM		0x0200
28 #define		TMP102_CONF_POL		0x0400
29 #define		TMP102_CONF_F0		0x0800
30 #define		TMP102_CONF_F1		0x1000
31 #define		TMP102_CONF_R0		0x2000
32 #define		TMP102_CONF_R1		0x4000
33 #define		TMP102_CONF_OS		0x8000
34 #define		TMP102_CONF_EM		0x0010
35 #define		TMP102_CONF_AL		0x0020
36 #define		TMP102_CONF_CR0		0x0040
37 #define		TMP102_CONF_CR1		0x0080
38 #define	TMP102_TLOW_REG			0x02
39 #define	TMP102_THIGH_REG		0x03
40 
41 #define TMP102_CONFREG_MASK	(TMP102_CONF_SD | TMP102_CONF_TM | \
42 				 TMP102_CONF_POL | TMP102_CONF_F0 | \
43 				 TMP102_CONF_F1 | TMP102_CONF_OS | \
44 				 TMP102_CONF_EM | TMP102_CONF_AL | \
45 				 TMP102_CONF_CR0 | TMP102_CONF_CR1)
46 
47 #define TMP102_CONFIG_CLEAR	(TMP102_CONF_SD | TMP102_CONF_OS | \
48 				 TMP102_CONF_CR0)
49 #define TMP102_CONFIG_SET	(TMP102_CONF_TM | TMP102_CONF_EM | \
50 				 TMP102_CONF_CR1)
51 
52 #define CONVERSION_TIME_MS		35	/* in milli-seconds */
53 
54 struct tmp102 {
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 */
61 static 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 */
67 static inline u16 tmp102_mC_to_reg(int val)
68 {
69 	return (val * 128) / 1000;
70 }
71 
72 static int tmp102_read(struct device *dev, enum hwmon_sensor_types type,
73 		       u32 attr, int channel, long *temp)
74 {
75 	struct tmp102 *tmp102 = dev_get_drvdata(dev);
76 	unsigned int regval;
77 	int err, reg;
78 
79 	switch (attr) {
80 	case hwmon_temp_input:
81 		/* Is it too early to return a conversion ? */
82 		if (time_before(jiffies, tmp102->ready_time)) {
83 			dev_dbg(dev, "%s: Conversion not ready yet..\n", __func__);
84 			return -EAGAIN;
85 		}
86 		reg = TMP102_TEMP_REG;
87 		break;
88 	case hwmon_temp_max_hyst:
89 		reg = TMP102_TLOW_REG;
90 		break;
91 	case hwmon_temp_max:
92 		reg = TMP102_THIGH_REG;
93 		break;
94 	default:
95 		return -EOPNOTSUPP;
96 	}
97 
98 	err = regmap_read(tmp102->regmap, reg, &regval);
99 	if (err < 0)
100 		return err;
101 	*temp = tmp102_reg_to_mC(regval);
102 
103 	return 0;
104 }
105 
106 static int tmp102_write(struct device *dev, enum hwmon_sensor_types type,
107 			u32 attr, int channel, long temp)
108 {
109 	struct tmp102 *tmp102 = dev_get_drvdata(dev);
110 	int reg;
111 
112 	switch (attr) {
113 	case hwmon_temp_max_hyst:
114 		reg = TMP102_TLOW_REG;
115 		break;
116 	case hwmon_temp_max:
117 		reg = TMP102_THIGH_REG;
118 		break;
119 	default:
120 		return -EOPNOTSUPP;
121 	}
122 
123 	temp = clamp_val(temp, -256000, 255000);
124 	return regmap_write(tmp102->regmap, reg, tmp102_mC_to_reg(temp));
125 }
126 
127 static umode_t tmp102_is_visible(const void *data, enum hwmon_sensor_types type,
128 				 u32 attr, int channel)
129 {
130 	if (type != hwmon_temp)
131 		return 0;
132 
133 	switch (attr) {
134 	case hwmon_temp_input:
135 		return 0444;
136 	case hwmon_temp_max_hyst:
137 	case hwmon_temp_max:
138 		return 0644;
139 	default:
140 		return 0;
141 	}
142 }
143 
144 static const struct hwmon_channel_info * const tmp102_info[] = {
145 	HWMON_CHANNEL_INFO(chip,
146 			   HWMON_C_REGISTER_TZ),
147 	HWMON_CHANNEL_INFO(temp,
148 			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST),
149 	NULL
150 };
151 
152 static const struct hwmon_ops tmp102_hwmon_ops = {
153 	.is_visible = tmp102_is_visible,
154 	.read = tmp102_read,
155 	.write = tmp102_write,
156 };
157 
158 static const struct hwmon_chip_info tmp102_chip_info = {
159 	.ops = &tmp102_hwmon_ops,
160 	.info = tmp102_info,
161 };
162 
163 static void tmp102_restore_config(void *data)
164 {
165 	struct tmp102 *tmp102 = data;
166 
167 	regmap_write(tmp102->regmap, TMP102_CONF_REG, tmp102->config_orig);
168 }
169 
170 static bool tmp102_is_writeable_reg(struct device *dev, unsigned int reg)
171 {
172 	return reg != TMP102_TEMP_REG;
173 }
174 
175 static bool tmp102_is_volatile_reg(struct device *dev, unsigned int reg)
176 {
177 	return reg == TMP102_TEMP_REG;
178 }
179 
180 static const struct regmap_config tmp102_regmap_config = {
181 	.reg_bits = 8,
182 	.val_bits = 16,
183 	.max_register = TMP102_THIGH_REG,
184 	.writeable_reg = tmp102_is_writeable_reg,
185 	.volatile_reg = tmp102_is_volatile_reg,
186 	.val_format_endian = REGMAP_ENDIAN_BIG,
187 	.cache_type = REGCACHE_MAPLE,
188 	.use_single_read = true,
189 	.use_single_write = true,
190 };
191 
192 static int tmp102_probe(struct i2c_client *client)
193 {
194 	struct device *dev = &client->dev;
195 	struct device *hwmon_dev;
196 	struct tmp102 *tmp102;
197 	unsigned int regval;
198 	int err;
199 
200 	if (!i2c_check_functionality(client->adapter,
201 				     I2C_FUNC_SMBUS_WORD_DATA)) {
202 		dev_err(dev,
203 			"adapter doesn't support SMBus word transactions\n");
204 		return -ENODEV;
205 	}
206 
207 	tmp102 = devm_kzalloc(dev, sizeof(*tmp102), GFP_KERNEL);
208 	if (!tmp102)
209 		return -ENOMEM;
210 
211 	i2c_set_clientdata(client, tmp102);
212 
213 	tmp102->regmap = devm_regmap_init_i2c(client, &tmp102_regmap_config);
214 	if (IS_ERR(tmp102->regmap))
215 		return PTR_ERR(tmp102->regmap);
216 
217 	err = regmap_read(tmp102->regmap, TMP102_CONF_REG, &regval);
218 	if (err < 0) {
219 		dev_err(dev, "error reading config register\n");
220 		return err;
221 	}
222 
223 	if ((regval & ~TMP102_CONFREG_MASK) !=
224 	    (TMP102_CONF_R0 | TMP102_CONF_R1)) {
225 		dev_err(dev, "unexpected config register value\n");
226 		return -ENODEV;
227 	}
228 
229 	tmp102->config_orig = regval;
230 
231 	err = devm_add_action_or_reset(dev, tmp102_restore_config, tmp102);
232 	if (err)
233 		return err;
234 
235 	regval &= ~TMP102_CONFIG_CLEAR;
236 	regval |= TMP102_CONFIG_SET;
237 
238 	err = regmap_write(tmp102->regmap, TMP102_CONF_REG, regval);
239 	if (err < 0) {
240 		dev_err(dev, "error writing config register\n");
241 		return err;
242 	}
243 
244 	/*
245 	 * Mark that we are not ready with data until the first
246 	 * conversion is complete
247 	 */
248 	tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS);
249 
250 	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
251 							 tmp102,
252 							 &tmp102_chip_info,
253 							 NULL);
254 	if (IS_ERR(hwmon_dev)) {
255 		dev_dbg(dev, "unable to register hwmon device\n");
256 		return PTR_ERR(hwmon_dev);
257 	}
258 	dev_info(dev, "initialized\n");
259 
260 	return 0;
261 }
262 
263 static int tmp102_suspend(struct device *dev)
264 {
265 	struct i2c_client *client = to_i2c_client(dev);
266 	struct tmp102 *tmp102 = i2c_get_clientdata(client);
267 
268 	return regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
269 				  TMP102_CONF_SD, TMP102_CONF_SD);
270 }
271 
272 static int tmp102_resume(struct device *dev)
273 {
274 	struct i2c_client *client = to_i2c_client(dev);
275 	struct tmp102 *tmp102 = i2c_get_clientdata(client);
276 	int err;
277 
278 	err = regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
279 				 TMP102_CONF_SD, 0);
280 
281 	tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS);
282 
283 	return err;
284 }
285 
286 static DEFINE_SIMPLE_DEV_PM_OPS(tmp102_dev_pm_ops, tmp102_suspend, tmp102_resume);
287 
288 static const struct i2c_device_id tmp102_id[] = {
289 	{ "tmp102", 0 },
290 	{ }
291 };
292 MODULE_DEVICE_TABLE(i2c, tmp102_id);
293 
294 static const struct of_device_id __maybe_unused tmp102_of_match[] = {
295 	{ .compatible = "ti,tmp102" },
296 	{ },
297 };
298 MODULE_DEVICE_TABLE(of, tmp102_of_match);
299 
300 static struct i2c_driver tmp102_driver = {
301 	.driver.name	= DRIVER_NAME,
302 	.driver.of_match_table = of_match_ptr(tmp102_of_match),
303 	.driver.pm	= pm_sleep_ptr(&tmp102_dev_pm_ops),
304 	.probe		= tmp102_probe,
305 	.id_table	= tmp102_id,
306 };
307 
308 module_i2c_driver(tmp102_driver);
309 
310 MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
311 MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
312 MODULE_LICENSE("GPL");
313