xref: /openbmc/linux/drivers/iio/pressure/hp206c.c (revision 7cf15f42)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * hp206c.c - HOPERF HP206C precision barometer and altimeter sensor
4  *
5  * Copyright (c) 2016, Intel Corporation.
6  *
7  * (7-bit I2C slave address 0x76)
8  *
9  * Datasheet:
10  *  http://www.hoperf.com/upload/sensor/HP206C_DataSheet_EN_V2.0.pdf
11  */
12 
13 #include <linux/module.h>
14 #include <linux/i2c.h>
15 #include <linux/iio/iio.h>
16 #include <linux/iio/sysfs.h>
17 #include <linux/delay.h>
18 #include <linux/util_macros.h>
19 #include <linux/acpi.h>
20 
21 #include <asm/unaligned.h>
22 
23 /* I2C commands: */
24 #define HP206C_CMD_SOFT_RST	0x06
25 
26 #define HP206C_CMD_ADC_CVT	0x40
27 
28 #define HP206C_CMD_ADC_CVT_OSR_4096	0x00
29 #define HP206C_CMD_ADC_CVT_OSR_2048	0x04
30 #define HP206C_CMD_ADC_CVT_OSR_1024	0x08
31 #define HP206C_CMD_ADC_CVT_OSR_512	0x0c
32 #define HP206C_CMD_ADC_CVT_OSR_256	0x10
33 #define HP206C_CMD_ADC_CVT_OSR_128	0x14
34 
35 #define HP206C_CMD_ADC_CVT_CHNL_PT	0x00
36 #define HP206C_CMD_ADC_CVT_CHNL_T	0x02
37 
38 #define HP206C_CMD_READ_P	0x30
39 #define HP206C_CMD_READ_T	0x32
40 
41 #define HP206C_CMD_READ_REG	0x80
42 #define HP206C_CMD_WRITE_REG	0xc0
43 
44 #define HP206C_REG_INT_EN	0x0b
45 #define HP206C_REG_INT_CFG	0x0c
46 
47 #define HP206C_REG_INT_SRC	0x0d
48 #define HP206C_FLAG_DEV_RDY	0x40
49 
50 #define HP206C_REG_PARA		0x0f
51 #define HP206C_FLAG_CMPS_EN	0x80
52 
53 /* Maximum spin for DEV_RDY */
54 #define HP206C_MAX_DEV_RDY_WAIT_COUNT 20
55 #define HP206C_DEV_RDY_WAIT_US    20000
56 
57 struct hp206c_data {
58 	struct mutex mutex;
59 	struct i2c_client *client;
60 	int temp_osr_index;
61 	int pres_osr_index;
62 };
63 
64 struct hp206c_osr_setting {
65 	u8 osr_mask;
66 	unsigned int temp_conv_time_us;
67 	unsigned int pres_conv_time_us;
68 };
69 
70 /* Data from Table 5 in datasheet. */
71 static const struct hp206c_osr_setting hp206c_osr_settings[] = {
72 	{ HP206C_CMD_ADC_CVT_OSR_4096,	65600,	131100	},
73 	{ HP206C_CMD_ADC_CVT_OSR_2048,	32800,	65600	},
74 	{ HP206C_CMD_ADC_CVT_OSR_1024,	16400,	32800	},
75 	{ HP206C_CMD_ADC_CVT_OSR_512,	8200,	16400	},
76 	{ HP206C_CMD_ADC_CVT_OSR_256,	4100,	8200	},
77 	{ HP206C_CMD_ADC_CVT_OSR_128,	2100,	4100	},
78 };
79 static const int hp206c_osr_rates[] = { 4096, 2048, 1024, 512, 256, 128 };
80 static const char hp206c_osr_rates_str[] = "4096 2048 1024 512 256 128";
81 
hp206c_read_reg(struct i2c_client * client,u8 reg)82 static inline int hp206c_read_reg(struct i2c_client *client, u8 reg)
83 {
84 	return i2c_smbus_read_byte_data(client, HP206C_CMD_READ_REG | reg);
85 }
86 
hp206c_write_reg(struct i2c_client * client,u8 reg,u8 val)87 static inline int hp206c_write_reg(struct i2c_client *client, u8 reg, u8 val)
88 {
89 	return i2c_smbus_write_byte_data(client,
90 			HP206C_CMD_WRITE_REG | reg, val);
91 }
92 
hp206c_read_20bit(struct i2c_client * client,u8 cmd)93 static int hp206c_read_20bit(struct i2c_client *client, u8 cmd)
94 {
95 	int ret;
96 	u8 values[3];
97 
98 	ret = i2c_smbus_read_i2c_block_data(client, cmd, sizeof(values), values);
99 	if (ret < 0)
100 		return ret;
101 	if (ret != sizeof(values))
102 		return -EIO;
103 	return get_unaligned_be24(&values[0]) & GENMASK(19, 0);
104 }
105 
106 /* Spin for max 160ms until DEV_RDY is 1, or return error. */
hp206c_wait_dev_rdy(struct iio_dev * indio_dev)107 static int hp206c_wait_dev_rdy(struct iio_dev *indio_dev)
108 {
109 	int ret;
110 	int count = 0;
111 	struct hp206c_data *data = iio_priv(indio_dev);
112 	struct i2c_client *client = data->client;
113 
114 	while (++count <= HP206C_MAX_DEV_RDY_WAIT_COUNT) {
115 		ret = hp206c_read_reg(client, HP206C_REG_INT_SRC);
116 		if (ret < 0) {
117 			dev_err(&indio_dev->dev, "Failed READ_REG INT_SRC: %d\n", ret);
118 			return ret;
119 		}
120 		if (ret & HP206C_FLAG_DEV_RDY)
121 			return 0;
122 		usleep_range(HP206C_DEV_RDY_WAIT_US, HP206C_DEV_RDY_WAIT_US * 3 / 2);
123 	}
124 	return -ETIMEDOUT;
125 }
126 
hp206c_set_compensation(struct i2c_client * client,bool enabled)127 static int hp206c_set_compensation(struct i2c_client *client, bool enabled)
128 {
129 	int val;
130 
131 	val = hp206c_read_reg(client, HP206C_REG_PARA);
132 	if (val < 0)
133 		return val;
134 	if (enabled)
135 		val |= HP206C_FLAG_CMPS_EN;
136 	else
137 		val &= ~HP206C_FLAG_CMPS_EN;
138 
139 	return hp206c_write_reg(client, HP206C_REG_PARA, val);
140 }
141 
142 /* Do a soft reset */
hp206c_soft_reset(struct iio_dev * indio_dev)143 static int hp206c_soft_reset(struct iio_dev *indio_dev)
144 {
145 	int ret;
146 	struct hp206c_data *data = iio_priv(indio_dev);
147 	struct i2c_client *client = data->client;
148 
149 	ret = i2c_smbus_write_byte(client, HP206C_CMD_SOFT_RST);
150 	if (ret) {
151 		dev_err(&client->dev, "Failed to reset device: %d\n", ret);
152 		return ret;
153 	}
154 
155 	usleep_range(400, 600);
156 
157 	ret = hp206c_wait_dev_rdy(indio_dev);
158 	if (ret) {
159 		dev_err(&client->dev, "Device not ready after soft reset: %d\n", ret);
160 		return ret;
161 	}
162 
163 	ret = hp206c_set_compensation(client, true);
164 	if (ret)
165 		dev_err(&client->dev, "Failed to enable compensation: %d\n", ret);
166 	return ret;
167 }
168 
hp206c_conv_and_read(struct iio_dev * indio_dev,u8 conv_cmd,u8 read_cmd,unsigned int sleep_us)169 static int hp206c_conv_and_read(struct iio_dev *indio_dev,
170 				u8 conv_cmd, u8 read_cmd,
171 				unsigned int sleep_us)
172 {
173 	int ret;
174 	struct hp206c_data *data = iio_priv(indio_dev);
175 	struct i2c_client *client = data->client;
176 
177 	ret = hp206c_wait_dev_rdy(indio_dev);
178 	if (ret < 0) {
179 		dev_err(&indio_dev->dev, "Device not ready: %d\n", ret);
180 		return ret;
181 	}
182 
183 	ret = i2c_smbus_write_byte(client, conv_cmd);
184 	if (ret < 0) {
185 		dev_err(&indio_dev->dev, "Failed convert: %d\n", ret);
186 		return ret;
187 	}
188 
189 	usleep_range(sleep_us, sleep_us * 3 / 2);
190 
191 	ret = hp206c_wait_dev_rdy(indio_dev);
192 	if (ret < 0) {
193 		dev_err(&indio_dev->dev, "Device not ready: %d\n", ret);
194 		return ret;
195 	}
196 
197 	ret = hp206c_read_20bit(client, read_cmd);
198 	if (ret < 0)
199 		dev_err(&indio_dev->dev, "Failed read: %d\n", ret);
200 
201 	return ret;
202 }
203 
hp206c_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)204 static int hp206c_read_raw(struct iio_dev *indio_dev,
205 			   struct iio_chan_spec const *chan, int *val,
206 			   int *val2, long mask)
207 {
208 	int ret;
209 	struct hp206c_data *data = iio_priv(indio_dev);
210 	const struct hp206c_osr_setting *osr_setting;
211 	u8 conv_cmd;
212 
213 	mutex_lock(&data->mutex);
214 
215 	switch (mask) {
216 	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
217 		switch (chan->type) {
218 		case IIO_TEMP:
219 			*val = hp206c_osr_rates[data->temp_osr_index];
220 			ret = IIO_VAL_INT;
221 			break;
222 
223 		case IIO_PRESSURE:
224 			*val = hp206c_osr_rates[data->pres_osr_index];
225 			ret = IIO_VAL_INT;
226 			break;
227 		default:
228 			ret = -EINVAL;
229 		}
230 		break;
231 
232 	case IIO_CHAN_INFO_RAW:
233 		switch (chan->type) {
234 		case IIO_TEMP:
235 			osr_setting = &hp206c_osr_settings[data->temp_osr_index];
236 			conv_cmd = HP206C_CMD_ADC_CVT |
237 					osr_setting->osr_mask |
238 					HP206C_CMD_ADC_CVT_CHNL_T;
239 			ret = hp206c_conv_and_read(indio_dev,
240 					conv_cmd,
241 					HP206C_CMD_READ_T,
242 					osr_setting->temp_conv_time_us);
243 			if (ret >= 0) {
244 				/* 20 significant bits are provided.
245 				 * Extend sign over the rest.
246 				 */
247 				*val = sign_extend32(ret, 19);
248 				ret = IIO_VAL_INT;
249 			}
250 			break;
251 
252 		case IIO_PRESSURE:
253 			osr_setting = &hp206c_osr_settings[data->pres_osr_index];
254 			conv_cmd = HP206C_CMD_ADC_CVT |
255 					osr_setting->osr_mask |
256 					HP206C_CMD_ADC_CVT_CHNL_PT;
257 			ret = hp206c_conv_and_read(indio_dev,
258 					conv_cmd,
259 					HP206C_CMD_READ_P,
260 					osr_setting->pres_conv_time_us);
261 			if (ret >= 0) {
262 				*val = ret;
263 				ret = IIO_VAL_INT;
264 			}
265 			break;
266 		default:
267 			ret = -EINVAL;
268 		}
269 		break;
270 
271 	case IIO_CHAN_INFO_SCALE:
272 		switch (chan->type) {
273 		case IIO_TEMP:
274 			*val = 0;
275 			*val2 = 10000;
276 			ret = IIO_VAL_INT_PLUS_MICRO;
277 			break;
278 
279 		case IIO_PRESSURE:
280 			*val = 0;
281 			*val2 = 1000;
282 			ret = IIO_VAL_INT_PLUS_MICRO;
283 			break;
284 		default:
285 			ret = -EINVAL;
286 		}
287 		break;
288 
289 	default:
290 		ret = -EINVAL;
291 	}
292 
293 	mutex_unlock(&data->mutex);
294 	return ret;
295 }
296 
hp206c_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)297 static int hp206c_write_raw(struct iio_dev *indio_dev,
298 			    struct iio_chan_spec const *chan,
299 			    int val, int val2, long mask)
300 {
301 	int ret = 0;
302 	struct hp206c_data *data = iio_priv(indio_dev);
303 
304 	if (mask != IIO_CHAN_INFO_OVERSAMPLING_RATIO)
305 		return -EINVAL;
306 	mutex_lock(&data->mutex);
307 	switch (chan->type) {
308 	case IIO_TEMP:
309 		data->temp_osr_index = find_closest_descending(val,
310 			hp206c_osr_rates, ARRAY_SIZE(hp206c_osr_rates));
311 		break;
312 	case IIO_PRESSURE:
313 		data->pres_osr_index = find_closest_descending(val,
314 			hp206c_osr_rates, ARRAY_SIZE(hp206c_osr_rates));
315 		break;
316 	default:
317 		ret = -EINVAL;
318 	}
319 	mutex_unlock(&data->mutex);
320 	return ret;
321 }
322 
323 static const struct iio_chan_spec hp206c_channels[] = {
324 	{
325 		.type = IIO_TEMP,
326 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
327 				      BIT(IIO_CHAN_INFO_SCALE) |
328 				      BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
329 	},
330 	{
331 		.type = IIO_PRESSURE,
332 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
333 				      BIT(IIO_CHAN_INFO_SCALE) |
334 				      BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
335 	}
336 };
337 
338 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(hp206c_osr_rates_str);
339 
340 static struct attribute *hp206c_attributes[] = {
341 	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
342 	NULL,
343 };
344 
345 static const struct attribute_group hp206c_attribute_group = {
346 	.attrs = hp206c_attributes,
347 };
348 
349 static const struct iio_info hp206c_info = {
350 	.attrs = &hp206c_attribute_group,
351 	.read_raw = hp206c_read_raw,
352 	.write_raw = hp206c_write_raw,
353 };
354 
hp206c_probe(struct i2c_client * client)355 static int hp206c_probe(struct i2c_client *client)
356 {
357 	const struct i2c_device_id *id = i2c_client_get_device_id(client);
358 	struct iio_dev *indio_dev;
359 	struct hp206c_data *data;
360 	int ret;
361 
362 	if (!i2c_check_functionality(client->adapter,
363 				     I2C_FUNC_SMBUS_BYTE |
364 				     I2C_FUNC_SMBUS_BYTE_DATA |
365 				     I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
366 		dev_err(&client->dev, "Adapter does not support "
367 				"all required i2c functionality\n");
368 		return -ENODEV;
369 	}
370 
371 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
372 	if (!indio_dev)
373 		return -ENOMEM;
374 
375 	data = iio_priv(indio_dev);
376 	data->client = client;
377 	mutex_init(&data->mutex);
378 
379 	indio_dev->info = &hp206c_info;
380 	indio_dev->name = id->name;
381 	indio_dev->modes = INDIO_DIRECT_MODE;
382 	indio_dev->channels = hp206c_channels;
383 	indio_dev->num_channels = ARRAY_SIZE(hp206c_channels);
384 
385 	i2c_set_clientdata(client, indio_dev);
386 
387 	/* Do a soft reset on probe */
388 	ret = hp206c_soft_reset(indio_dev);
389 	if (ret) {
390 		dev_err(&client->dev, "Failed to reset on startup: %d\n", ret);
391 		return -ENODEV;
392 	}
393 
394 	return devm_iio_device_register(&client->dev, indio_dev);
395 }
396 
397 static const struct i2c_device_id hp206c_id[] = {
398 	{"hp206c"},
399 	{}
400 };
401 MODULE_DEVICE_TABLE(i2c, hp206c_id);
402 
403 #ifdef CONFIG_ACPI
404 static const struct acpi_device_id hp206c_acpi_match[] = {
405 	{"HOP206C", 0},
406 	{ },
407 };
408 MODULE_DEVICE_TABLE(acpi, hp206c_acpi_match);
409 #endif
410 
411 static struct i2c_driver hp206c_driver = {
412 	.probe = hp206c_probe,
413 	.id_table = hp206c_id,
414 	.driver = {
415 		.name = "hp206c",
416 		.acpi_match_table = ACPI_PTR(hp206c_acpi_match),
417 	},
418 };
419 
420 module_i2c_driver(hp206c_driver);
421 
422 MODULE_DESCRIPTION("HOPERF HP206C precision barometer and altimeter sensor");
423 MODULE_AUTHOR("Leonard Crestez <leonard.crestez@intel.com>");
424 MODULE_LICENSE("GPL v2");
425