linux/drivers/hwmon/shtc1.c
Thomas Gleixner c942fddf87 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
Based on 3 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [kishon] [vijay] [abraham]
  [i] [kishon]@[ti] [com] this program is distributed in the hope that
  it will be useful but without any warranty without even the implied
  warranty of merchantability or fitness for a particular purpose see
  the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [graeme] [gregory]
  [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
  [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
  [hk] [hemahk]@[ti] [com] this program is distributed in the hope
  that it will be useful but without any warranty without even the
  implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1105 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:37 -07:00

242 lines
6.4 KiB
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 */
#define SHTC1_ID 0x07
#define SHTC1_ID_REG_MASK 0x1f
/* delays for non-blocking i2c commands, both in us */
#define SHTC1_NONBLOCKING_WAIT_TIME_HPM 14400
#define SHTC1_NONBLOCKING_WAIT_TIME_LPM 1000
#define SHTC1_CMD_LENGTH 2
#define SHTC1_RESPONSE_LENGTH 6
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;
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 = SHTC1_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 = SHTC1_NONBLOCKING_WAIT_TIME_LPM;
}
}
static int shtc1_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
int ret;
char id_reg[2];
struct shtc1_data *data;
struct device *hwmon_dev;
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, sizeof(id_reg));
if (ret != sizeof(id_reg)) {
dev_err(dev, "could not read ID register: %d\n", ret);
return -ENODEV;
}
if ((id_reg[1] & SHTC1_ID_REG_MASK) != SHTC1_ID) {
dev_err(dev, "ID register doesn't 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;
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", 0 },
{ "shtw1", 0 },
{ }
};
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");