ens210.c

  1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * ens210.c - Support for ScioSense ens210 temperature & humidity sensor family
  4 *
  5 * (7-bit I2C slave address 0x43 ENS210)
  6 * (7-bit I2C slave address 0x43 ENS210A)
  7 * (7-bit I2C slave address 0x44 ENS211)
  8 * (7-bit I2C slave address 0x45 ENS212)
  9 * (7-bit I2C slave address 0x46 ENS213A)
 10 * (7-bit I2C slave address 0x47 ENS215)
 11 *
 12 * Datasheet:
 13 *  https://www.sciosense.com/wp-content/uploads/2024/04/ENS21x-Datasheet.pdf
 14 *  https://www.sciosense.com/wp-content/uploads/2023/12/ENS210-Datasheet.pdf
 15 */
 16
 17#include <linux/crc7.h>
 18#include <linux/delay.h>
 19#include <linux/i2c.h>
 20#include <linux/iio/iio.h>
 21#include <linux/mod_devicetable.h>
 22#include <linux/module.h>
 23#include <linux/types.h>
 24
 25#include <linux/unaligned.h>
 26
 27/* register definitions */
 28#define ENS210_REG_PART_ID		0x00
 29#define ENS210_REG_DIE_REV		0x02
 30#define ENS210_REG_UID			0x04
 31#define ENS210_REG_SYS_CTRL		0x10
 32#define ENS210_REG_SYS_STAT		0x11
 33#define ENS210_REG_SENS_RUN		0x21
 34#define ENS210_REG_SENS_START		0x22
 35#define ENS210_REG_SENS_STOP		0x23
 36#define ENS210_REG_SENS_STAT		0x24
 37#define ENS210_REG_T_VAL		0x30
 38#define ENS210_REG_H_VAL		0x33
 39
 40/* value definitions */
 41#define ENS210_SENS_START_T_START		BIT(0)
 42#define ENS210_SENS_START_H_START		BIT(1)
 43
 44#define ENS210_SENS_STAT_T_ACTIVE		BIT(0)
 45#define ENS210_SENS_STAT_H_ACTIVE		BIT(1)
 46
 47#define ENS210_SYS_CTRL_LOW_POWER_ENABLE	BIT(0)
 48#define ENS210_SYS_CTRL_SYS_RESET		BIT(7)
 49
 50#define ENS210_SYS_STAT_SYS_ACTIVE		BIT(0)
 51
 52enum ens210_partnumber {
 53	ENS210	= 0x0210,
 54	ENS210A	= 0xa210,
 55	ENS211	= 0x0211,
 56	ENS212	= 0x0212,
 57	ENS213A	= 0xa213,
 58	ENS215	= 0x0215,
 59};
 60
 61/**
 62 * struct ens210_chip_info - Humidity/Temperature chip specific information
 63 * @name:		name of device
 64 * @part_id:		chip identifier
 65 * @conv_time_msec:	time for conversion calculation in m/s
 66 */
 67struct ens210_chip_info {
 68	const char *name;
 69	enum ens210_partnumber part_id;
 70	unsigned int conv_time_msec;
 71};
 72
 73/**
 74 * struct ens210_data - Humidity/Temperature sensor device structure
 75 * @client:	i2c client
 76 * @chip_info:	chip specific information
 77 * @lock:	lock protecting against simultaneous callers of get_measurement
 78 *		since multiple uninterrupted transactions are required
 79 */
 80struct ens210_data {
 81	struct i2c_client *client;
 82	const struct ens210_chip_info *chip_info;
 83	struct mutex lock;
 84};
 85
 86/* calculate 17-bit crc7 */
 87static u8 ens210_crc7(u32 val)
 88{
 89	unsigned int val_be = (val & 0x1ffff) >> 0x8;
 90
 91	return crc7_be(0xde, (u8 *)&val_be, 3) >> 1;
 92}
 93
 94static int ens210_get_measurement(struct iio_dev *indio_dev, bool temp, int *val)
 95{
 96	struct ens210_data *data = iio_priv(indio_dev);
 97	struct device *dev = &data->client->dev;
 98	u32 regval;
 99	u8 regval_le[3];
100	int ret;
101
102	/* assert read */
103	ret = i2c_smbus_write_byte_data(data->client, ENS210_REG_SENS_START,
104					temp ? ENS210_SENS_START_T_START :
105					       ENS210_SENS_START_H_START);
106	if (ret)
107		return ret;
108
109	/* wait for conversion to be ready */
110	msleep(data->chip_info->conv_time_msec);
111
112	ret = i2c_smbus_read_byte_data(data->client, ENS210_REG_SENS_STAT);
113	if (ret < 0)
114		return ret;
115
116	/* perform read */
117	ret = i2c_smbus_read_i2c_block_data(
118		data->client, temp ? ENS210_REG_T_VAL : ENS210_REG_H_VAL, 3,
119		regval_le);
120	if (ret < 0) {
121		dev_err(dev, "failed to read register");
122		return -EIO;
123	}
124	if (ret != 3) {
125		dev_err(dev, "expected 3 bytes, received %d\n", ret);
126		return -EIO;
127	}
128
129	regval = get_unaligned_le24(regval_le);
130	if (ens210_crc7(regval) != ((regval >> 17) & 0x7f)) {
131		dev_err(dev, "invalid crc\n");
132		return -EIO;
133	}
134
135	if (!((regval >> 16) & 0x1)) {
136		dev_err(dev, "data is not valid");
137		return -EIO;
138	}
139
140	*val = regval & GENMASK(15, 0);
141	return IIO_VAL_INT;
142}
143
144static int ens210_read_raw(struct iio_dev *indio_dev,
145			   struct iio_chan_spec const *channel, int *val,
146			   int *val2, long mask)
147{
148	struct ens210_data *data = iio_priv(indio_dev);
149	int ret;
150
151	switch (mask) {
152	case IIO_CHAN_INFO_RAW:
153		scoped_guard(mutex, &data->lock) {
154			ret = ens210_get_measurement(
155				indio_dev, channel->type == IIO_TEMP, val);
156			if (ret)
157				return ret;
158			return IIO_VAL_INT;
159		}
160		return -EINVAL; /* compiler warning workaround */
161	case IIO_CHAN_INFO_SCALE:
162		if (channel->type == IIO_TEMP) {
163			*val = 15;
164			*val2 = 625000;
165		} else {
166			*val = 1;
167			*val2 = 953125;
168		}
169		return IIO_VAL_INT_PLUS_MICRO;
170	case IIO_CHAN_INFO_OFFSET:
171		*val = -17481;
172		*val2 = 600000;
173		return IIO_VAL_INT_PLUS_MICRO;
174	default:
175		return -EINVAL;
176	}
177}
178
179static const struct iio_chan_spec ens210_channels[] = {
180	{
181		.type = IIO_TEMP,
182		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
183				      BIT(IIO_CHAN_INFO_SCALE) |
184				      BIT(IIO_CHAN_INFO_OFFSET),
185	},
186	{
187		.type = IIO_HUMIDITYRELATIVE,
188		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
189				      BIT(IIO_CHAN_INFO_SCALE),
190	}
191};
192
193static const struct iio_info ens210_info = {
194	.read_raw = ens210_read_raw,
195};
196
197static int ens210_probe(struct i2c_client *client)
198{
199	struct ens210_data *data;
200	struct iio_dev *indio_dev;
201	uint16_t part_id;
202	int ret;
203
204	if (!i2c_check_functionality(client->adapter,
205				     I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
206				     I2C_FUNC_SMBUS_WRITE_BYTE |
207				     I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
208		return dev_err_probe(&client->dev, -EOPNOTSUPP,
209			"adapter does not support some i2c transactions\n");
210	}
211
212	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
213	if (!indio_dev)
214		return -ENOMEM;
215
216	data = iio_priv(indio_dev);
217	data->client = client;
218	mutex_init(&data->lock);
219	data->chip_info = i2c_get_match_data(client);
220
221	ret = devm_regulator_get_enable(&client->dev, "vdd");
222	if (ret)
223		return ret;
224
225	/* reset device */
226	ret = i2c_smbus_write_byte_data(client, ENS210_REG_SYS_CTRL,
227					ENS210_SYS_CTRL_SYS_RESET);
228	if (ret)
229		return ret;
230
231	/* wait for device to become active */
232	usleep_range(4000, 5000);
233
234	/* disable low power mode */
235	ret = i2c_smbus_write_byte_data(client, ENS210_REG_SYS_CTRL, 0x00);
236	if (ret)
237		return ret;
238
239	/* wait for device to finish */
240	usleep_range(4000, 5000);
241
242	/* get part_id */
243	ret = i2c_smbus_read_word_data(client, ENS210_REG_PART_ID);
244	if (ret < 0)
245		return ret;
246	part_id = ret;
247
248	if (part_id != data->chip_info->part_id) {
249		dev_info(&client->dev,
250			 "Part ID does not match (0x%04x != 0x%04x)\n", part_id,
251			 data->chip_info->part_id);
252	}
253
254	/* reenable low power */
255	ret = i2c_smbus_write_byte_data(client, ENS210_REG_SYS_CTRL,
256					ENS210_SYS_CTRL_LOW_POWER_ENABLE);
257	if (ret)
258		return ret;
259
260	indio_dev->name = data->chip_info->name;
261	indio_dev->modes = INDIO_DIRECT_MODE;
262	indio_dev->channels = ens210_channels;
263	indio_dev->num_channels = ARRAY_SIZE(ens210_channels);
264	indio_dev->info = &ens210_info;
265
266	return devm_iio_device_register(&client->dev, indio_dev);
267}
268
269static const struct ens210_chip_info ens210_chip_info_data = {
270	.name = "ens210",
271	.part_id = ENS210,
272	.conv_time_msec = 130,
273};
274
275static const struct ens210_chip_info ens210a_chip_info_data = {
276	.name = "ens210a",
277	.part_id = ENS210A,
278	.conv_time_msec = 130,
279};
280
281static const struct ens210_chip_info ens211_chip_info_data = {
282	.name = "ens211",
283	.part_id = ENS211,
284	.conv_time_msec = 32,
285};
286
287static const struct ens210_chip_info ens212_chip_info_data = {
288	.name = "ens212",
289	.part_id = ENS212,
290	.conv_time_msec = 32,
291};
292
293static const struct ens210_chip_info ens213a_chip_info_data = {
294	.name = "ens213a",
295	.part_id = ENS213A,
296	.conv_time_msec = 130,
297};
298
299static const struct ens210_chip_info ens215_chip_info_data = {
300	.name = "ens215",
301	.part_id = ENS215,
302	.conv_time_msec = 130,
303};
304
305static const struct of_device_id ens210_of_match[] = {
306	{ .compatible = "sciosense,ens210", .data = &ens210_chip_info_data },
307	{ .compatible = "sciosense,ens210a", .data = &ens210a_chip_info_data },
308	{ .compatible = "sciosense,ens211", .data = &ens211_chip_info_data },
309	{ .compatible = "sciosense,ens212", .data = &ens212_chip_info_data },
310	{ .compatible = "sciosense,ens213a", .data = &ens213a_chip_info_data },
311	{ .compatible = "sciosense,ens215", .data = &ens215_chip_info_data },
312	{ }
313};
314MODULE_DEVICE_TABLE(of, ens210_of_match);
315
316static const struct i2c_device_id ens210_id_table[] = {
317	{ "ens210", (kernel_ulong_t)&ens210_chip_info_data },
318	{ "ens210a", (kernel_ulong_t)&ens210a_chip_info_data },
319	{ "ens211", (kernel_ulong_t)&ens211_chip_info_data },
320	{ "ens212", (kernel_ulong_t)&ens212_chip_info_data },
321	{ "ens213a", (kernel_ulong_t)&ens213a_chip_info_data },
322	{ "ens215", (kernel_ulong_t)&ens215_chip_info_data },
323	{ }
324};
325MODULE_DEVICE_TABLE(i2c, ens210_id_table);
326
327static struct i2c_driver ens210_driver = {
328	.probe = ens210_probe,
329	.id_table = ens210_id_table,
330	.driver = {
331		.name = "ens210",
332		.of_match_table = ens210_of_match,
333	},
334};
335module_i2c_driver(ens210_driver);
336
337MODULE_DESCRIPTION("ScioSense ENS210 temperature and humidity sensor driver");
338MODULE_AUTHOR("Joshua Felmeden <jfelmeden@thegoodpenguin.co.uk>");
339MODULE_LICENSE("GPL");