On 05/08/15 05:41, Matt Ranostay wrote:
> Add support for the PulsedLight LIDAR rangefinder sensor which allows
> high speed (over 300Hz) distance measurements using Barker Coding within
> 40 meter range.
>
> Support only tested on the "blue label" rev 2, but may work using low
> sample frequencies on the original version.
>
> Signed-off-by: Matt Ranostay <mranos...@gmail.com>
Couple of bits inline. Only one that really matters is I suspect
that simply calling it lidar (and naming the file lidar.c) is going
to give us problems if they or someone else produces a similar lidar
device in future.
Perhaps file name as pulsedlight-lidar-lite-v2.c
and name as lidar-lite-v2 for device tree etc.
Otherwise, nice little driver for a nice looking bit of kit.
Thanks,
Jonathan
> ---
> drivers/iio/proximity/Kconfig | 12 ++
> drivers/iio/proximity/Makefile | 1 +
> drivers/iio/proximity/lidar.c | 294
> +++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 307 insertions(+)
> create mode 100644 drivers/iio/proximity/lidar.c
>
> diff --git a/drivers/iio/proximity/Kconfig b/drivers/iio/proximity/Kconfig
> index 41a8d8f..e64fc5b 100644
> --- a/drivers/iio/proximity/Kconfig
> +++ b/drivers/iio/proximity/Kconfig
> @@ -20,6 +20,18 @@ endmenu
>
> menu "Proximity sensors"
>
> +config LIDAR
> + tristate "PulsedLight LIDAR sensor"
> + select IIO_BUFFER
> + select IIO_TRIGGERED_BUFFER
> + depends on I2C
> + help
> + Say Y to build a driver for PulsedLight LIDAR range finding
> + sensor.
> +
> + To compile this driver as a module, choose M here: the
> + module will be called lidar.
> +
> config SX9500
> tristate "SX9500 Semtech proximity sensor"
> select IIO_BUFFER
> diff --git a/drivers/iio/proximity/Makefile b/drivers/iio/proximity/Makefile
> index 9818dc5..36a95f3 100644
> --- a/drivers/iio/proximity/Makefile
> +++ b/drivers/iio/proximity/Makefile
> @@ -4,4 +4,5 @@
>
> # When adding new entries keep the list in alphabetical order
> obj-$(CONFIG_AS3935) += as3935.o
> +obj-$(CONFIG_LIDAR) += lidar.o
> obj-$(CONFIG_SX9500) += sx9500.o
> diff --git a/drivers/iio/proximity/lidar.c b/drivers/iio/proximity/lidar.c
> new file mode 100644
> index 0000000..fdec9a2
> --- /dev/null
> +++ b/drivers/iio/proximity/lidar.c
> @@ -0,0 +1,294 @@
> +/*
> + * lidar.c - Support for PulsedLight LIDAR range finding sensor
> + *
> + * Copyright (C) 2015 Matt Ranostay <mranos...@gmail.com>
> + *
> + * 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.
> + *
> + * TODO: runtime pm, interrupt mode, and signal strength reporting
> + *
> + */
> +
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/i2c.h>
> +#include <linux/delay.h>
> +#include <linux/mutex.h>
> +#include <linux/module.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/trigger.h>
> +#include <linux/iio/triggered_buffer.h>
> +#include <linux/iio/trigger_consumer.h>
> +
> +#define LIDAR_REG_CONTROL 0x00
> +#define LIDAR_REG_CONTROL_ACQUIRE BIT(2)
> +
> +#define LIDAR_REG_STATUS 0x01
> +#define LIDAR_REG_STATUS_INVALID BIT(3)
> +#define LIDAR_REG_STATUS_READY BIT(0)
> +
> +#define LIDAR_REG_DATA_HBYTE 0x0f
> +#define LIDAR_REG_DATA_LBYTE 0x10
> +
> +#define LIDAR_DRV_NAME "lidar"
> +
> +struct lidar_data {
> + struct mutex lock;
> + struct iio_dev *indio_dev;
> + struct i2c_client *client;
> +
> + u16 buffer[8]; /* 2 byte distance + 8 byte timestamp */
> +};
> +
> +static const struct iio_chan_spec lidar_channels[] = {
> + {
> + .type = IIO_DISTANCE,
> + .info_mask_separate =
> + BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
> + .scan_index = 0,
> + .scan_type = {
> + .sign = 'u',
> + .realbits = 16,
> + .storagebits = 16,
> + },
> + },
> + IIO_CHAN_SOFT_TIMESTAMP(1),
> +};
> +
> +static int lidar_read_byte(struct lidar_data *data, int reg)
> +{
> + struct i2c_client *client = data->client;
> + int ret;
> +
> + ret = i2c_smbus_write_byte(client, reg);
> + if (ret < 0) {
> + dev_err(&client->dev, "cannot write addr value");
> + return ret;
> + }
> +
> + ret = i2c_smbus_read_byte(client);
> + if (ret < 0) {
> + dev_err(&client->dev, "cannot read data value");
> + return ret;
Drop this return ret as otherwise various static checkers
will moan at me (falling through gives the same result)
> + }
> +
> + return ret;
> +}
> +
> +static inline int lidar_write_control(struct lidar_data *data, int val)
> +{
> + return i2c_smbus_write_byte_data(data->client, LIDAR_REG_CONTROL, val);
> +}
> +
> +static int lidar_read_measurement(struct lidar_data *data, u16 *reg)
> +{
> + int ret;
> + int val;
> +
> + /*
> + * Device needs a STOP condition between address write, and data read
> + * so in turn i2c_smbus_read_byte_data cannot be used
Good documentation of this. However, I'd move it to inside the read_byte
function above rather than here.
> + */
> +
> + ret = lidar_read_byte(data, LIDAR_REG_DATA_HBYTE);
> + if (ret < 0)
> + return ret;
> + val = ret << 8;
> +
> + ret = lidar_read_byte(data, LIDAR_REG_DATA_LBYTE);
> + if (ret < 0)
> + return ret;
> +
> + val |= ret;
> + *reg = val;
> +
> + return 0;
> +}
> +
> +static int lidar_get_measurement(struct lidar_data *data, u16 *reg)
> +{
> + struct i2c_client *client = data->client;
> + int tries = 10;
> + int ret;
> +
> + /* start sample */
> + ret = lidar_write_control(data, LIDAR_REG_CONTROL_ACQUIRE);
> + if (ret < 0) {
> + dev_err(&client->dev, "cannot send start measurement command");
> + return ret;
> + }
> +
> + while (tries--) {
> + usleep_range(1000, 2000);
> +
> + ret = lidar_read_byte(data, LIDAR_REG_STATUS);
> + if (ret < 0)
> + break;
> +
> + /* return 0 since laser is likely pointed out of range */
> + if (ret & LIDAR_REG_STATUS_INVALID) {
> + *reg = 0;
> + ret = 0;
> + break;
> + }
> +
> + /* sample ready to read */
> + if (!(ret & LIDAR_REG_STATUS_READY)) {
> + ret = lidar_read_measurement(data, reg);
> + break;
> + }
> + ret = -EIO;
> + }
> +
> + return ret;
> +}
> +
> +static int lidar_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int *val, int *val2, long mask)
> +{
> + struct lidar_data *data = iio_priv(indio_dev);
> + int ret = -EINVAL;
> +
> + mutex_lock(&data->lock);
> +
> + if (iio_buffer_enabled(indio_dev) && mask == IIO_CHAN_INFO_RAW) {
> + ret = -EBUSY;
> + goto error_busy;
> + }
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW: {
> + u16 reg;
> +
> + ret = lidar_get_measurement(data, ®);
> + if (!ret) {
> + *val = reg;
> + ret = IIO_VAL_INT;
> + }
> + break;
> + }
> + case IIO_CHAN_INFO_SCALE:
> + *val = 0;
> + *val2 = 10000;
> + ret = IIO_VAL_INT_PLUS_MICRO;
> + break;
> + }
> +
> +error_busy:
> + mutex_unlock(&data->lock);
> +
> + return ret;
> +}
> +
> +static irqreturn_t lidar_trigger_handler(int irq, void *private)
> +{
> + struct iio_poll_func *pf = private;
> + struct iio_dev *indio_dev = pf->indio_dev;
> + struct lidar_data *data = iio_priv(indio_dev);
> + int ret;
> +
> + ret = lidar_get_measurement(data, &data->buffer[0]);
data->buffer should be the same pointer unless I'm going crazy (always
a posibility)
> + if (!ret) {
> + iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
> + iio_get_time_ns());
> + } else {
> + dev_err(&data->client->dev, "cannot read LIDAR measurement");
> + }
> +
> + iio_trigger_notify_done(indio_dev->trig);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static const struct iio_info lidar_info = {
> + .driver_module = THIS_MODULE,
> + .read_raw = lidar_read_raw,
> +};
> +
> +static int lidar_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct lidar_data *data;
> + struct iio_dev *indio_dev;
> + int ret;
> +
> + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
> + if (!indio_dev)
> + return -ENOMEM;
> +
> + indio_dev->info = &lidar_info;
> + indio_dev->name = LIDAR_DRV_NAME;
> + indio_dev->channels = lidar_channels;
> + indio_dev->num_channels = ARRAY_SIZE(lidar_channels);
> + indio_dev->modes = INDIO_DIRECT_MODE;
> +
> + data = iio_priv(indio_dev);
> + i2c_set_clientdata(client, indio_dev);
> +
> + data->client = client;
> + data->indio_dev = indio_dev;
> + mutex_init(&data->lock);
> +
> + ret = iio_triggered_buffer_setup(indio_dev, NULL,
> + lidar_trigger_handler, NULL);
> + if (ret)
> + return ret;
> +
> + ret = iio_device_register(indio_dev);
> + if (ret)
> + goto error_unreg_buffer;
> +
> + return 0;
> +
> +error_unreg_buffer:
> + iio_triggered_buffer_cleanup(indio_dev);
> +
> + return ret;
> +}
> +
> +static int lidar_remove(struct i2c_client *client)
> +{
> + struct iio_dev *indio_dev = i2c_get_clientdata(client);
> +
> + iio_device_unregister(indio_dev);
> + iio_triggered_buffer_cleanup(indio_dev);
> +
> + return 0;
> +}
> +
> +static const struct i2c_device_id lidar_id[] = {
> + {"lidar", 0},
> + { },
> +};
> +MODULE_DEVICE_TABLE(i2c, lidar_id);
> +
> +static const struct of_device_id lidar_dt_ids[] = {
> + { .compatible = "pulsedlight,lidar" },
Not a more descriptive name? Website suggests
things like
lidar-lite-v2
I just worry they'll come out with a completely incompatible
interface to some new unit that is also a lidar and we'll be
forever confused!
> + { }
> +};
> +
> +static struct i2c_driver lidar_driver = {
> + .driver = {
> + .name = LIDAR_DRV_NAME,
> + .of_match_table = of_match_ptr(lidar_dt_ids),
> + },
> + .probe = lidar_probe,
> + .remove = lidar_remove,
> + .id_table = lidar_id,
> +};
> +module_i2c_driver(lidar_driver);
> +
> +MODULE_AUTHOR("Matt Ranostay <mranos...@gmail.com>");
> +MODULE_DESCRIPTION("PulsedLight LIDAR sensor");
> +MODULE_LICENSE("GPL");
>
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