[linux-2.6-block.git] / drivers / hwmon / shtc1.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* Sensirion SHTC1 humidity and temperature sensor driver
 *
 * Copyright (C) 2014 Sensirion AG, Switzerland
 * Author: Johannes Winkelmann <johannes.winkelmann@sensirion.com>
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/platform_data/shtc1.h>

/* commands (high precision mode) */
static const unsigned char shtc1_cmd_measure_blocking_hpm[]    = { 0x7C, 0xA2 };
static const unsigned char shtc1_cmd_measure_nonblocking_hpm[] = { 0x78, 0x66 };

/* commands (low precision mode) */
static const unsigned char shtc1_cmd_measure_blocking_lpm[]    = { 0x64, 0x58 };
static const unsigned char shtc1_cmd_measure_nonblocking_lpm[] = { 0x60, 0x9c };

/* command for reading the ID register */
static const unsigned char shtc1_cmd_read_id_reg[]             = { 0xef, 0xc8 };

/*
 * constants for reading the ID register
 * SHTC1: 0x0007 with mask 0x003f
 * SHTW1: 0x0007 with mask 0x003f
 * SHTC3: 0x0807 with mask 0x083f
 */
#define SHTC3_ID      0x0807
#define SHTC3_ID_MASK 0x083f
#define SHTC1_ID      0x0007
#define SHTC1_ID_MASK 0x003f

/* delays for non-blocking i2c commands, both in us */
#define SHTC1_NONBLOCKING_WAIT_TIME_HPM  14400
#define SHTC1_NONBLOCKING_WAIT_TIME_LPM   1000
#define SHTC3_NONBLOCKING_WAIT_TIME_HPM  12100
#define SHTC3_NONBLOCKING_WAIT_TIME_LPM    800

#define SHTC1_CMD_LENGTH      2
#define SHTC1_RESPONSE_LENGTH 6

enum shtcx_chips {
	shtc1,
	shtc3,
};

struct shtc1_data {
	struct i2c_client *client;
	struct mutex update_lock;
	bool valid;
	unsigned long last_updated; /* in jiffies */

	const unsigned char *command;
	unsigned int nonblocking_wait_time; /* in us */

	struct shtc1_platform_data setup;
	enum shtcx_chips chip;

	int temperature; /* 1000 * temperature in dgr C */
	int humidity; /* 1000 * relative humidity in %RH */
};

static int shtc1_update_values(struct i2c_client *client,
			       struct shtc1_data *data,
			       char *buf, int bufsize)
{
	int ret = i2c_master_send(client, data->command, SHTC1_CMD_LENGTH);
	if (ret != SHTC1_CMD_LENGTH) {
		dev_err(&client->dev, "failed to send command: %d\n", ret);
		return ret < 0 ? ret : -EIO;
	}

	/*
	 * In blocking mode (clock stretching mode) the I2C bus
	 * is blocked for other traffic, thus the call to i2c_master_recv()
	 * will wait until the data is ready. For non blocking mode, we
	 * have to wait ourselves.
	 */
	if (!data->setup.blocking_io)
		usleep_range(data->nonblocking_wait_time,
			     data->nonblocking_wait_time + 1000);

	ret = i2c_master_recv(client, buf, bufsize);
	if (ret != bufsize) {
		dev_err(&client->dev, "failed to read values: %d\n", ret);
		return ret < 0 ? ret : -EIO;
	}

	return 0;
}

/* sysfs attributes */
static struct shtc1_data *shtc1_update_client(struct device *dev)
{
	struct shtc1_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;
	unsigned char buf[SHTC1_RESPONSE_LENGTH];
	int val;
	int ret = 0;

	mutex_lock(&data->update_lock);

	if (time_after(jiffies, data->last_updated + HZ / 10) || !data->valid) {
		ret = shtc1_update_values(client, data, buf, sizeof(buf));
		if (ret)
			goto out;

		/*
		 * From datasheet:
		 * T = -45 + 175 * ST / 2^16
		 * RH = 100 * SRH / 2^16
		 *
		 * Adapted for integer fixed point (3 digit) arithmetic.
		 */
		val = be16_to_cpup((__be16 *)buf);
		data->temperature = ((21875 * val) >> 13) - 45000;
		val = be16_to_cpup((__be16 *)(buf + 3));
		data->humidity = ((12500 * val) >> 13);

		data->last_updated = jiffies;
		data->valid = true;
	}

out:
	mutex_unlock(&data->update_lock);

	return ret == 0 ? data : ERR_PTR(ret);
}

static ssize_t temp1_input_show(struct device *dev,
				struct device_attribute *attr,
				char *buf)
{
	struct shtc1_data *data = shtc1_update_client(dev);
	if (IS_ERR(data))
		return PTR_ERR(data);

	return sprintf(buf, "%d\n", data->temperature);
}

static ssize_t humidity1_input_show(struct device *dev,
				    struct device_attribute *attr, char *buf)
{
	struct shtc1_data *data = shtc1_update_client(dev);
	if (IS_ERR(data))
		return PTR_ERR(data);

	return sprintf(buf, "%d\n", data->humidity);
}

static DEVICE_ATTR_RO(temp1_input);
static DEVICE_ATTR_RO(humidity1_input);

static struct attribute *shtc1_attrs[] = {
	&dev_attr_temp1_input.attr,
	&dev_attr_humidity1_input.attr,
	NULL
};

ATTRIBUTE_GROUPS(shtc1);

static void shtc1_select_command(struct shtc1_data *data)
{
	if (data->setup.high_precision) {
		data->command = data->setup.blocking_io ?
				shtc1_cmd_measure_blocking_hpm :
				shtc1_cmd_measure_nonblocking_hpm;
		data->nonblocking_wait_time = (data->chip == shtc1) ?
				SHTC1_NONBLOCKING_WAIT_TIME_HPM :
				SHTC3_NONBLOCKING_WAIT_TIME_HPM;
	} else {
		data->command = data->setup.blocking_io ?
				shtc1_cmd_measure_blocking_lpm :
				shtc1_cmd_measure_nonblocking_lpm;
		data->nonblocking_wait_time = (data->chip == shtc1) ?
				SHTC1_NONBLOCKING_WAIT_TIME_LPM :
				SHTC3_NONBLOCKING_WAIT_TIME_LPM;
	}
}

static int shtc1_probe(struct i2c_client *client,
		       const struct i2c_device_id *id)
{
	int ret;
	u16 id_reg;
	char id_reg_buf[2];
	struct shtc1_data *data;
	struct device *hwmon_dev;
	enum shtcx_chips chip = id->driver_data;
	struct i2c_adapter *adap = client->adapter;
	struct device *dev = &client->dev;

	if (!i2c_check_functionality(adap, I2C_FUNC_I2C)) {
		dev_err(dev, "plain i2c transactions not supported\n");
		return -ENODEV;
	}

	ret = i2c_master_send(client, shtc1_cmd_read_id_reg, SHTC1_CMD_LENGTH);
	if (ret != SHTC1_CMD_LENGTH) {
		dev_err(dev, "could not send read_id_reg command: %d\n", ret);
		return ret < 0 ? ret : -ENODEV;
	}
	ret = i2c_master_recv(client, id_reg_buf, sizeof(id_reg_buf));
	if (ret != sizeof(id_reg_buf)) {
		dev_err(dev, "could not read ID register: %d\n", ret);
		return -ENODEV;
	}

	id_reg = be16_to_cpup((__be16 *)id_reg_buf);
	if (chip == shtc3) {
		if ((id_reg & SHTC3_ID_MASK) != SHTC3_ID) {
			dev_err(dev, "SHTC3 ID register does not match\n");
			return -ENODEV;
		}
	} else if ((id_reg & SHTC1_ID_MASK) != SHTC1_ID) {
		dev_err(dev, "SHTC1 ID register does not match\n");
		return -ENODEV;
	}

	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	data->setup.blocking_io = false;
	data->setup.high_precision = true;
	data->client = client;
	data->chip = chip;

	if (client->dev.platform_data)
		data->setup = *(struct shtc1_platform_data *)dev->platform_data;
	shtc1_select_command(data);
	mutex_init(&data->update_lock);

	hwmon_dev = devm_hwmon_device_register_with_groups(dev,
							   client->name,
							   data,
							   shtc1_groups);
	if (IS_ERR(hwmon_dev))
		dev_dbg(dev, "unable to register hwmon device\n");

	return PTR_ERR_OR_ZERO(hwmon_dev);
}

/* device ID table */
static const struct i2c_device_id shtc1_id[] = {
	{ "shtc1", shtc1 },
	{ "shtw1", shtc1 },
	{ "shtc3", shtc3 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, shtc1_id);

static struct i2c_driver shtc1_i2c_driver = {
	.driver.name  = "shtc1",
	.probe        = shtc1_probe,
	.id_table     = shtc1_id,
};

module_i2c_driver(shtc1_i2c_driver);

MODULE_AUTHOR("Johannes Winkelmann <johannes.winkelmann@sensirion.com>");
MODULE_DESCRIPTION("Sensirion SHTC1 humidity and temperature sensor driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
c942fddf	1	// SPDX-License-Identifier: GPL-2.0-or-later
1a539d37 TP	2	/* Sensirion SHTC1 humidity and temperature sensor driver
	3	*
	4	* Copyright (C) 2014 Sensirion AG, Switzerland
	5	* Author: Johannes Winkelmann <johannes.winkelmann@sensirion.com>
1a539d37 TP	6	*/
	7
	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/delay.h>
	16	#include <linux/platform_data/shtc1.h>
	17
	18	/* commands (high precision mode) */
	19	static const unsigned char shtc1_cmd_measure_blocking_hpm[] = { 0x7C, 0xA2 };
	20	static const unsigned char shtc1_cmd_measure_nonblocking_hpm[] = { 0x78, 0x66 };
	21
	22	/* commands (low precision mode) */
	23	static const unsigned char shtc1_cmd_measure_blocking_lpm[] = { 0x64, 0x58 };
	24	static const unsigned char shtc1_cmd_measure_nonblocking_lpm[] = { 0x60, 0x9c };
	25
	26	/* command for reading the ID register */
ffd96868	27	static const unsigned char shtc1_cmd_read_id_reg[] = { 0xef, 0xc8 };
1a539d37	28
ffd96868 DR	29	/*
	30	* constants for reading the ID register
	31	* SHTC1: 0x0007 with mask 0x003f
	32	* SHTW1: 0x0007 with mask 0x003f
	33	* SHTC3: 0x0807 with mask 0x083f
	34	*/
	35	#define SHTC3_ID 0x0807
	36	#define SHTC3_ID_MASK 0x083f
	37	#define SHTC1_ID 0x0007
	38	#define SHTC1_ID_MASK 0x003f
1a539d37 TP	39
	40	/* delays for non-blocking i2c commands, both in us */
	41	#define SHTC1_NONBLOCKING_WAIT_TIME_HPM 14400
	42	#define SHTC1_NONBLOCKING_WAIT_TIME_LPM 1000
ffd96868 DR	43	#define SHTC3_NONBLOCKING_WAIT_TIME_HPM 12100
ffd96868 DR	44	#define SHTC3_NONBLOCKING_WAIT_TIME_LPM 800
1a539d37 TP	45
	46	#define SHTC1_CMD_LENGTH 2
	47	#define SHTC1_RESPONSE_LENGTH 6
	48
ffd96868 DR	49	enum shtcx_chips {
	50	shtc1,
	51	shtc3,
	52	};
	53
1a539d37 TP	54	struct shtc1_data {
	55	struct i2c_client *client;
	56	struct mutex update_lock;
	57	bool valid;
	58	unsigned long last_updated; /* in jiffies */
	59
	60	const unsigned char *command;
	61	unsigned int nonblocking_wait_time; /* in us */
	62
	63	struct shtc1_platform_data setup;
ffd96868	64	enum shtcx_chips chip;
1a539d37 TP	65
	66	int temperature; /* 1000 * temperature in dgr C */
	67	int humidity; /* 1000 * relative humidity in %RH */
	68	};
	69
	70	static int shtc1_update_values(struct i2c_client *client,
	71	struct shtc1_data *data,
	72	char *buf, int bufsize)
	73	{
	74	int ret = i2c_master_send(client, data->command, SHTC1_CMD_LENGTH);
	75	if (ret != SHTC1_CMD_LENGTH) {
	76	dev_err(&client->dev, "failed to send command: %d\n", ret);
	77	return ret < 0 ? ret : -EIO;
	78	}
	79
	80	/*
	81	* In blocking mode (clock stretching mode) the I2C bus
	82	* is blocked for other traffic, thus the call to i2c_master_recv()
	83	* will wait until the data is ready. For non blocking mode, we
	84	* have to wait ourselves.
	85	*/
	86	if (!data->setup.blocking_io)
	87	usleep_range(data->nonblocking_wait_time,
	88	data->nonblocking_wait_time + 1000);
	89
	90	ret = i2c_master_recv(client, buf, bufsize);
	91	if (ret != bufsize) {
	92	dev_err(&client->dev, "failed to read values: %d\n", ret);
	93	return ret < 0 ? ret : -EIO;
	94	}
	95
	96	return 0;
	97	}
	98
	99	/* sysfs attributes */
	100	static struct shtc1_data shtc1_update_client(struct device dev)
	101	{
	102	struct shtc1_data *data = dev_get_drvdata(dev);
	103	struct i2c_client *client = data->client;
	104	unsigned char buf[SHTC1_RESPONSE_LENGTH];
	105	int val;
	106	int ret = 0;
	107
	108	mutex_lock(&data->update_lock);
	109
	110	if (time_after(jiffies, data->last_updated + HZ / 10) \|\| !data->valid) {
	111	ret = shtc1_update_values(client, data, buf, sizeof(buf));
	112	if (ret)
	113	goto out;
	114
	115	/*
	116	* From datasheet:
	117	* T = -45 + 175 * ST / 2^16
	118	* RH = 100 * SRH / 2^16
	119	*
	120	* Adapted for integer fixed point (3 digit) arithmetic.
	121	*/
	122	val = be16_to_cpup((__be16 *)buf);
	123	data->temperature = ((21875 * val) >> 13) - 45000;
	124	val = be16_to_cpup((__be16 *)(buf + 3));
	125	data->humidity = ((12500 * val) >> 13);
	126
	127	data->last_updated = jiffies;
	128	data->valid = true;
129	}
130
131	out:
132	mutex_unlock(&data->update_lock);
133
134	return ret == 0 ? data : ERR_PTR(ret);
135	}
136
137	static ssize_t temp1_input_show(struct device *dev,
138	struct device_attribute *attr,
139	char *buf)
140	{
141	struct shtc1_data *data = shtc1_update_client(dev);
142	if (IS_ERR(data))
143	return PTR_ERR(data);
144
145	return sprintf(buf, "%d\n", data->temperature);
146	}
147
148	static ssize_t humidity1_input_show(struct device *dev,
149	struct device_attribute attr, char buf)
150	{
151	struct shtc1_data *data = shtc1_update_client(dev);
152	if (IS_ERR(data))
153	return PTR_ERR(data);
154
155	return sprintf(buf, "%d\n", data->humidity);
156	}
157
158	static DEVICE_ATTR_RO(temp1_input);
159	static DEVICE_ATTR_RO(humidity1_input);
160
161	static struct attribute *shtc1_attrs[] = {
162	&dev_attr_temp1_input.attr,
163	&dev_attr_humidity1_input.attr,
164	NULL
165	};
166
167	ATTRIBUTE_GROUPS(shtc1);
168
169	static void shtc1_select_command(struct shtc1_data *data)
170	{
171	if (data->setup.high_precision) {
172	data->command = data->setup.blocking_io ?
173	shtc1_cmd_measure_blocking_hpm :
174	shtc1_cmd_measure_nonblocking_hpm;
ffd96868 DR	175	data->nonblocking_wait_time = (data->chip == shtc1) ?
	176	SHTC1_NONBLOCKING_WAIT_TIME_HPM :
	177	SHTC3_NONBLOCKING_WAIT_TIME_HPM;
1a539d37 TP	178	} else {
	179	data->command = data->setup.blocking_io ?
	180	shtc1_cmd_measure_blocking_lpm :
	181	shtc1_cmd_measure_nonblocking_lpm;
ffd96868 DR	182	data->nonblocking_wait_time = (data->chip == shtc1) ?
	183	SHTC1_NONBLOCKING_WAIT_TIME_LPM :
	184	SHTC3_NONBLOCKING_WAIT_TIME_LPM;
1a539d37 TP	185	}
	186	}
	187
	188	static int shtc1_probe(struct i2c_client *client,
	189	const struct i2c_device_id *id)
	190	{
	191	int ret;
ffd96868 DR	192	u16 id_reg;
ffd96868 DR	193	char id_reg_buf[2];
1a539d37 TP	194	struct shtc1_data *data;
1a539d37 TP	195	struct device *hwmon_dev;
ffd96868	196	enum shtcx_chips chip = id->driver_data;
1a539d37 TP	197	struct i2c_adapter *adap = client->adapter;
	198	struct device *dev = &client->dev;
	199
	200	if (!i2c_check_functionality(adap, I2C_FUNC_I2C)) {
	201	dev_err(dev, "plain i2c transactions not supported\n");
	202	return -ENODEV;
	203	}
	204
	205	ret = i2c_master_send(client, shtc1_cmd_read_id_reg, SHTC1_CMD_LENGTH);
	206	if (ret != SHTC1_CMD_LENGTH) {
	207	dev_err(dev, "could not send read_id_reg command: %d\n", ret);
	208	return ret < 0 ? ret : -ENODEV;
	209	}
ffd96868 DR	210	ret = i2c_master_recv(client, id_reg_buf, sizeof(id_reg_buf));
ffd96868 DR	211	if (ret != sizeof(id_reg_buf)) {
1a539d37 TP	212	dev_err(dev, "could not read ID register: %d\n", ret);
	213	return -ENODEV;
	214	}
ffd96868 DR	215
	216	id_reg = be16_to_cpup((__be16 *)id_reg_buf);
	217	if (chip == shtc3) {
	218	if ((id_reg & SHTC3_ID_MASK) != SHTC3_ID) {
	219	dev_err(dev, "SHTC3 ID register does not match\n");
	220	return -ENODEV;
	221	}
	222	} else if ((id_reg & SHTC1_ID_MASK) != SHTC1_ID) {
	223	dev_err(dev, "SHTC1 ID register does not match\n");
1a539d37 TP	224	return -ENODEV;
	225	}
	226
	227	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
	228	if (!data)
	229	return -ENOMEM;
	230
	231	data->setup.blocking_io = false;
	232	data->setup.high_precision = true;
	233	data->client = client;
ffd96868	234	data->chip = chip;
1a539d37 TP	235
	236	if (client->dev.platform_data)
	237	data->setup = (struct shtc1_platform_data )dev->platform_data;
	238	shtc1_select_command(data);
	239	mutex_init(&data->update_lock);
	240
	241	hwmon_dev = devm_hwmon_device_register_with_groups(dev,
	242	client->name,
	243	data,
	244	shtc1_groups);
	245	if (IS_ERR(hwmon_dev))
	246	dev_dbg(dev, "unable to register hwmon device\n");
	247
	248	return PTR_ERR_OR_ZERO(hwmon_dev);
	249	}
	250
	251	/* device ID table */
	252	static const struct i2c_device_id shtc1_id[] = {
ffd96868 DR	253	{ "shtc1", shtc1 },
	254	{ "shtw1", shtc1 },
	255	{ "shtc3", shtc3 },
1a539d37 TP	256	{ }
	257	};
	258	MODULE_DEVICE_TABLE(i2c, shtc1_id);
	259
	260	static struct i2c_driver shtc1_i2c_driver = {
	261	.driver.name = "shtc1",
	262	.probe = shtc1_probe,
	263	.id_table = shtc1_id,
	264	};
	265
	266	module_i2c_driver(shtc1_i2c_driver);
	267
	268	MODULE_AUTHOR("Johannes Winkelmann <johannes.winkelmann@sensirion.com>");
	269	MODULE_DESCRIPTION("Sensirion SHTC1 humidity and temperature sensor driver");
	270	MODULE_LICENSE("GPL");