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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;
/*
* triggered buffer
* 1x16-bit channel + 3x16 padding + 4x16 timestamp
*/
s16 buffer[8];
/* 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->buffer[0] = sensor_data;
iio_push_to_buffers_with_timestamp(indio_dev,
data->buffer, 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)
|