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/*
* srf08.c - Support for Devantech SRFxx ultrasonic ranger
* with i2c interface
* actually supported are srf02, srf08, srf10
*
* Copyright (c) 2016, 2017 Andreas Klinger <ak@it-klinger.de>
*
* This file is subject to the terms and conditions of version 2 of
* the GNU General Public License. See the file COPYING in the main
* directory of this archive for more details.
*
* For details about the device see:
* http://www.robot-electronics.co.uk/htm/srf08tech.html
* http://www.robot-electronics.co.uk/htm/srf10tech.htm
* http://www.robot-electronics.co.uk/htm/srf02tech.htm
*/
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
/* registers of SRF08 device */
#define SRF08_WRITE_COMMAND 0x00 /* Command Register */
#define SRF08_WRITE_MAX_GAIN 0x01 /* Max Gain Register: 0 .. 31 */
#define SRF08_WRITE_RANGE 0x02 /* Range Register: 0 .. 255 */
#define SRF08_READ_SW_REVISION 0x00 /* Software Revision */
#define SRF08_READ_LIGHT 0x01 /* Light Sensor during last echo */
#define SRF08_READ_ECHO_1_HIGH 0x02 /* Range of first echo received */
#define SRF08_READ_ECHO_1_LOW 0x03 /* Range of first echo received */
#define SRF08_CMD_RANGING_CM 0x51 /* Ranging Mode - Result in cm */
enum srf08_sensor_type {
SRF02,
SRF08,
SRF10,
SRF_MAX_TYPE
};
struct srf08_chip_info {
const int *sensitivity_avail;
int num_sensitivity_avail;
int sensitivity_default;
/* default value of Range in mm */
int range_default;
};
struct srf08_data {
struct i2c_client *client;
/*
* Gain in the datasheet is called sensitivity here to distinct it
* from the gain used with amplifiers of adc's
*/
int sensitivity;
/* max. Range in mm */
int range_mm;
struct mutex lock;
/* Ensure timestamp is naturally aligned */
struct {
s16 chan;
s64 timestamp __aligned(8);
} scan;
/* Sensor-Type */
enum srf08_sensor_type sensor_type;
/* Chip-specific information */
const struct srf08_chip_info *chip_info;
};
/*
* in the documentation one can read about the "Gain" of the device
* which is used here for amplifying the signal and filtering out unwanted
* ones.
* But with ADC's this term is already used differently and that's why it
* is called "Sensitivity" here.
*/
static const struct srf08_chip_info srf02_chip_info = {
.sensitivity_avail = NULL,
.num_sensitivity_avail = 0,
.sensitivity_default = 0,
.range_default = 0,
};
static const int srf08_sensitivity_avail[] = {
94, 97, 100, 103, 107, 110, 114, 118,
123, 128, 133, 139, 145, 152, 159, 168,
177, 187, 199, 212, 227, 245, 265, 288,
317, 352, 395, 450, 524, 626, 777, 1025
};
static const struct srf08_chip_info srf08_chip_info = {
.sensitivity_avail = srf08_sensitivity_avail,
.num_sensitivity_avail = ARRAY_SIZE(srf08_sensitivity_avail),
.sensitivity_default = 1025,
.range_default = 6020,
};
static const int srf10_sensitivity_avail[] = {
40, 40, 50, 60, 70, 80, 100, 120,
140, 200, 250, 300, 350, 400, 500, 600,
700,
};
static const struct srf08_chip_info srf10_chip_info = {
.sensitivity_avail = srf10_sensitivity_avail,
.num_sensitivity_avail = ARRAY_SIZE(srf10_sensitivity_avail),
.sensitivity_default = 700,
.range_default = 6020,
};
static int srf08_read_ranging(struct srf08_data *data)
{
struct i2c_client *client = data->client;
int ret, i;
int waittime;
mutex_lock(&data->lock);
ret = i2c_smbus_write_byte_data(data->client,
SRF08_WRITE_COMMAND, SRF08_CMD_RANGING_CM);
if (ret < 0) {
dev_err(&client->dev, "write command - err: %d\n", ret);
mutex_unlock(&data->lock);
return ret;
}
/*
* we read here until a correct version number shows up as
* suggested by the documentation
*
* with an ultrasonic speed of 343 m/s and a roundtrip of it
* sleep the expected duration and try to read from the device
* if nothing useful is read try it in a shorter grid
*
* polling for not more than 20 ms should be enough
*/
waittime = 1 + data->range_mm / 172;
msleep(waittime);
for (i = 0; i < 4; i++) {
ret = i2c_smbus_read_byte_data(data->client,
SRF08_READ_SW_REVISION);
/* check if a valid version number is read */
if (ret < 255 && ret > 0)
break;
msleep(5);
}
if (ret >= 255 || ret <= 0) {
dev_err(&client->dev, "device not ready\n");
mutex_unlock(&data->lock);
return -EIO;
}
ret = i2c_smbus_read_word_swapped(data->client,
SRF08_READ_ECHO_1_HIGH);
if (ret < 0) {
dev_err(&client->dev, "cannot read distance: ret=%d\n", ret);
mutex_unlock(&data->lock);
return ret;
}
mutex_unlock(&data->lock);
return ret;
}
static irqreturn_t srf08_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct srf08_data *data = iio_priv(indio_dev);
s16 sensor_data;
sensor_data = srf08_read_ranging(data);
if (sensor_data < 0)
goto err;
mutex_lock(&data->lock);
data->scan.chan = sensor_data;
iio_push_to_buffers_with_timestamp(indio_dev,
&data->scan, pf->timestamp);
mutex_unlock(&data->lock);
err:
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static int srf08_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *channel, int *val,
int *val2, long mask)
{
struct srf08_data *data = iio_priv(indio_dev);
int ret;
if (channel->type != IIO_DISTANCE)
return -EINVAL;
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = srf08_read_ranging(data);
if (ret < 0)
return ret;
*val = ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
/* 1 LSB is 1 cm */
*val = 0;
*val2 = 10000;
return IIO_VAL_INT_PLUS_MICRO;
default:
return -EINVAL;
}
}
static ssize_t srf08_show_range_mm_available(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "[0.043 0.043 11.008]\n");
}
static IIO_DEVICE_ATTR(sensor_max_range_available, S_IRUGO,
srf08_show_range_mm_available, NULL, 0);
static ssize_t srf08_show_range_mm(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct srf08_data *data = iio_priv(indio_dev);
return sprintf(buf, "%d.%03d\n", data->range_mm / 1000,
data->range_mm % 1000);
}
/*
* set the range of the sensor to an even multiple of 43 mm
* which corresponds to 1 LSB in the register
*
* register value corresponding range
* 0x00 43 mm
* 0x01 86 mm
* 0x02 129 mm
* ...
* 0xFF 11008 mm
*/
static ssize_t srf08_write_range_mm(struct srf08_data *data, unsigned int val)
{
int ret;
struct i2c_client *client = data->client;
unsigned int mod;
u8 regval;
ret = val / 43 - 1;
mod = val % 43;
if (mod || (ret < 0) || (ret > 255))
return -EINVAL;
regval = ret;
mutex_lock(&data->lock);
ret = i2c_smbus_write_byte_data(client, SRF08_WRITE_RANGE, regval);
if (ret < 0) {
dev_err(&client->dev, "write_range - err: %d\n", ret);
mutex_unlock(&data->lock);
return ret;
}
data->range_mm = val;
mutex_unlock(&data->lock);
return 0;
}
static ssize_t srf08_store_range_mm(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct srf08_data *data = iio_priv(indio_dev);
int ret;
int integer, fract;
ret = iio_str_to_fixpoint(buf, 100, &integer, &fract);
if (ret)
return ret;
ret = srf08_write_range_mm(data, integer * 1000 + fract);
if (ret < 0)
return ret;
return len;
}
static IIO_DEVICE_ATTR(sensor_max_range, S_IRUGO | S_IWUSR,
srf08_show_range_mm, srf08_store_range_mm, 0);
static ssize_t srf08_show_sensitivity_available(struct device *dev,
struct device_attribute *attr, char *buf)
{
int i, len = 0;
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct srf08_data *data = iio_priv(indio_dev);
for (i = 0; i < data->chip_info->num_sensitivity_avail; i++)
if (data->chip_info->sensitivity_avail[i])
len += sprintf(buf + len, "%d ",
data->chip_info->sensitivity_avail[i]);
len += sprintf(buf + len, "\n");
return len;
}
static IIO_DEVICE_ATTR(sensor_sensitivity_available, S_IRUGO,
srf08_show_sensitivity_available, NULL, 0);
static ssize_t srf08_show_sensitivity(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct srf08_data *data = iio_priv(indio_dev);
int len;
len = sprintf(buf, "%d\n", data->sensitivity);
return len;
}
static ssize_t srf08_write_sensitivity(struct srf08_data *data,
unsigned int val)
{
struct i2c_client *client = data->client;
int ret, i;
u8 regval;
if (!val)
return -EINVAL;
for (i = 0; i < data->chip_info->num_sensitivity_avail; i++)
if (val && (val == data->chip_info->sensitivity_avail[i])) {
regval = i;
break;
}
if (i >= data->chip_info->num_sensitivity_avail)
return -EINVAL;
mutex_lock(&data->lock);
ret = i2c_smbus_write_byte_data(client, SRF08_WRITE_MAX_GAIN, regval);
if (ret < 0) {
dev_err(&client->dev, "write_sensitivity - err: %d\n", ret);
mutex_unlock(&data->lock);
return ret;
}
data->sensitivity = val;
mutex_unlock(&data->lock);
return 0;
}
static ssize_t srf08_store_sensitivity(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct srf08_data *data = iio_priv(indio_dev);
int ret;
unsigned int val;
ret = kstrtouint(buf, 10, &val);
if (ret)
return ret;
ret = srf08_write_sensitivity(data, val);
if (ret < 0)
return ret;
return len;
}
static IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR,
srf08_show_sensitivity, srf08_store_sensitivity, 0);
static struct attribute *srf08_attributes[] = {
&iio_dev_attr_sensor_max_range.dev_attr.attr,
&iio_dev_attr_sensor_max_range_available.dev_attr.attr,
&iio_dev_attr_sensor_sensitivity.dev_attr.attr,
&iio_dev_attr_sensor_sensitivity_available.dev_attr.attr,
NULL,
};
static const struct attribute_group srf08_attribute_group = {
.attrs = srf08_attributes,
};
static const struct iio_chan_spec srf08_channels[] = {
{
.type = IIO_DISTANCE,
.info_mask_separate =
BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
.scan_index = 0,
.scan_type = {
.sign = 's',
.realbits = 16,
.storagebits = 16,
.endianness = IIO_CPU,
},
},
IIO_CHAN_SOFT_TIMESTAMP(1),
};
static const struct iio_info srf08_info = {
.read_raw = srf08_read_raw,
.attrs = &srf08_attribute_group,
.driver_module = THIS_MODULE,
};
/*
* srf02 don't have an adjustable range or sensitivity,
* so we don't need attributes at all
*/
static const struct iio_info srf02_info = {
.read_raw = srf08_read_raw,
.driver_module = THIS_MODULE,
};
static int srf08_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct iio_dev *indio_dev;
struct srf08_data *data;
int ret;
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_READ_BYTE_DATA |
I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
I2C_FUNC_SMBUS_READ_WORD_DATA))
return -ENODEV;
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
data = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
data->client = client;
data->sensor_type = (enum srf08_sensor_type)id->driver_data;
switch (data->sensor_type) {
case SRF02:
data->chip_info = &srf02_chip_info;
indio_dev->info = &srf02_info;
break;
case SRF08:
data->chip_info = &srf08_chip_info;
indio_dev->info = &srf08_info;
break;
case SRF10:
data->chip_info = &srf10_chip_info;
indio_dev->info = &srf08_info;
break;
default:
return -EINVAL;
}
indio_dev->name = id->name;
indio_dev->dev.parent = &client->dev;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = srf08_channels;
indio_dev->num_channels = ARRAY_SIZE(srf08_channels);
mutex_init(&data->lock);
ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev,
iio_pollfunc_store_time, srf08_trigger_handler, NULL);
if (ret < 0) {
dev_err(&client->dev, "setup of iio triggered buffer failed\n");
return ret;
}
if (data->chip_info->range_default) {
/*
* set default range of device in mm here
* these register values cannot be read from the hardware
* therefore set driver specific default values
*
* srf02 don't have a default value so it'll be omitted
*/
ret = srf08_write_range_mm(data,
data->chip_info->range_default);
if (ret < 0)
return ret;
}
if (data->chip_info->sensitivity_default) {
/*
* set default sensitivity of device here
* these register values cannot be read from the hardware
* therefore set driver specific default values
*
* srf02 don't have a default value so it'll be omitted
*/
ret = srf08_write_sensitivity(data,
data->chip_info->sensitivity_default);
if (ret < 0)
return ret;
}
return devm_iio_device_register(&client->dev, indio_dev);
}
static const struct of_device_id of_srf08_match[] = {
{ .compatible = "devantech,srf02", (void *)SRF02},
{ .compatible = "devantech,srf08", (void *)SRF08},
{ .compatible = "devantech,srf10", (void *)SRF10},
{},
};
MODULE_DEVICE_TABLE(of, of_srf08_match);
static const struct i2c_device_id srf08_id[] = {
{ "srf02", SRF02 },
{ "srf08", SRF08 },
{ "srf10", SRF10 },
{ }
};
MODULE_DEVICE_TABLE(i2c, srf08_id);
static struct i2c_driver srf08_driver = {
.driver = {
.name = "srf08",
.of_match_table = of_srf08_match,
},
.probe = srf08_probe,
.id_table = srf08_id,
};
module_i2c_driver(srf08_driver);
MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
MODULE_DESCRIPTION("Devantech SRF02/SRF08/SRF10 i2c ultrasonic ranger driver");
MODULE_LICENSE("GPL");