Re: [PATCH 2/2] iio: proximity: add support for PulsedLight LIDAR

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On Sat, Aug 1, 2015 at 2:17 PM, Jonathan Cameron
<jic23@xxxxxxxxxxxxxxxxxxxxx> wrote:
>
>
>
> On 1 August 2015 09:39:11 BST, Vladimir Barinov <vladimir.barinov@xxxxxxxxxxxxxxxxxx> wrote:
>>Hi Matt,
>>
>>Find minor comments.
>>
>>On 01.08.2015 06:58, 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
>>polling
>>> at low sample frequencies on the original version.
>>>
>>> Signed-off-by: Matt Ranostay <mranostay@xxxxxxxxx>
>>> ---
>>>   drivers/iio/proximity/Kconfig  |  13 ++
>>>   drivers/iio/proximity/Makefile |   1 +
>>>   drivers/iio/proximity/lidar.c  | 309
>>+++++++++++++++++++++++++++++++++++++++++
>>Add ABI documentation
>>Documentation/ABI/testing/sysfs-bus-iio-proximity-lidar
> Why?  Reading on phone so may have missed something but all ABI is standard.
> Covered by top level docs.

Only thing that would be documented that IIO_DISTANCE is in meters.
But seems standard.
>
>>>   3 files changed, 323 insertions(+)
>>>   create mode 100644 drivers/iio/proximity/lidar.c
>>>
>>> diff --git a/drivers/iio/proximity/Kconfig
>>b/drivers/iio/proximity/Kconfig
>>> index 41a8d8f..8111e11 100644
>>> --- a/drivers/iio/proximity/Kconfig
>>> +++ b/drivers/iio/proximity/Kconfig
>>> @@ -20,6 +20,19 @@ endmenu
>>>
>>>   menu "Proximity sensors"
>>>
>>> +config LIDAR
>>> +    tristate "PulsedLight LIDAR sensor"
>>> +    select IIO_BUFFER
>>> +    select IIO_TRIGGERED_BUFFER
>>> +    select REGMAP_I2C
>>You did not use REGMAP in your driver.
>>Probably it would be better to use this API in your driver since the
>>chip seems fully SMBUS compatible.
> Unless there is a significant gain don't bother. Now if the device also has an spi bus
> or the driver does extensive caching it would be worthwhile.

Correctly, none of the the data is cacheable so regmap doesn't make sense here.

>
>>> +    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..e56df58
>>> --- /dev/null
>>> +++ b/drivers/iio/proximity/lidar.c
>>> @@ -0,0 +1,309 @@
>>> +/*
>>> + * lidar.c - Support for PulsedLight LIDAR range finding sensor
>>> + *
>>> + * Copyright (C) 2015 Matt Ranostay <mranostay@xxxxxxxxx>
>>> + *
>>> + * 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/module.h>
>>> +#include <linux/init.h>
>>> +#include <linux/delay.h>
>>> +#include <linux/mutex.h>
>>> +#include <linux/err.h>
>>> +#include <linux/i2c.h>
>>> +#include <linux/iio/iio.h>
>>> +#include <linux/iio/sysfs.h>
>>> +#include <linux/iio/trigger.h>
>>> +#include <linux/iio/trigger_consumer.h>
>>> +#include <linux/iio/buffer.h>
>>> +#include <linux/iio/triggered_buffer.h>
>>put it in alphabetic order
>>> +
>>> +#define LIDAR_REG_CONTROL   0x00
>>> +#define LIDAR_REG_CONTROL_ACQUIRE   BIT(2)
>>tab aligned
>>> +
>>> +#define LIDAR_REG_STATUS    0x01
>>> +#define LIDAR_REG_STATUS_RDY        BIT(0)
>>> +
>>> +#define LIDAR_REG_DATA_HBYTE        0x0f
>>> +#define LIDAR_REG_DATA_LBYTE        0x10
>>> +#define LIDAR_REG_DATA_MAX  0xffff
>>> +
>>> +#define LIDAR_DRV_NAME      "lidar"
>>> +
>>> +struct lidar_data {
>>> +    struct mutex lock;
>>> +    struct iio_dev *indio_dev;
>>> +    struct i2c_client *client;
>>> +
>>> +    /* config */
>>> +    int calib_bias;
>>> +
>>> +    u16 buffer[5]; /* 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_CALIBBIAS),
>>> +            .scan_index = 0,
>>> +            .scan_type = {
>>> +                    .sign = 'u',
>>> +                    .realbits = 16,
>>> +                    .storagebits = 16,
>>> +            },
>>> +    },
>>> +    IIO_CHAN_SOFT_TIMESTAMP(1),
>>> +};
>>> +
>>> +static inline 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;
>>> +    }
>>> +
>>> +    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;
>>> +
>>> +    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;
>>> +
>>> +    /* correct any possible overflow or underflow */
>>> +    val += data->calib_bias / 10000;
>>> +    if (val < 0)
>>> +            val = 0;
>>> +
>>> +    if (val > LIDAR_REG_DATA_MAX)
>>> +            val = LIDAR_REG_DATA_MAX;
>>> +
>>> +    *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;
>>> +
>>> +            /* sample ready to read */
>>> +            if (!(ret & LIDAR_REG_STATUS_RDY)) {
>>> +                    ret = lidar_read_measurement(data, reg);
>>> +                    break;
>>> +            }
>>> +    }
>>> +
>>> +    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;
>>> +
>>> +    if (iio_buffer_enabled(indio_dev) && mask == IIO_CHAN_INFO_RAW)
>>> +            return -EBUSY;
>>> +
>>> +    mutex_lock(&data->lock);
>>> +
>>> +    switch (mask) {
>>> +    case IIO_CHAN_INFO_RAW: {
>>> +            u16 reg;
>>> +
>>> +            ret = lidar_get_measurement(data, &reg);
>>> +            if (!ret) {
>>> +                    *val = reg / 100;
>>> +                    *val2 = (reg % 100) * 10000;
>>> +                    ret = IIO_VAL_INT_PLUS_MICRO;
>>> +            }
>>> +            break;
>>> +    }
>>> +    case IIO_CHAN_INFO_CALIBBIAS:
>>> +            *val = 0;
>>> +            *val2 = data->calib_bias;
>>> +            ret = IIO_VAL_INT_PLUS_MICRO;
>>> +            break;
>>> +    }
>>> +
>>> +    mutex_unlock(&data->lock);
>>> +
>>> +    return ret;
>>> +}
>>> +
>>> +static int lidar_write_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);
>>> +
>>> +    if (mask == IIO_CHAN_INFO_CALIBBIAS) {
>>> +            if (val != 0)
>>> +                    return -EINVAL;
>>> +
>>> +            /* cm increments only */
>>> +            if (val2 % 10000)
>>> +                    return -EINVAL;
>>> +
>>> +            mutex_lock(&data->lock);
>>> +            data->calib_bias = val2;
>>> +            mutex_unlock(&data->lock);
>>> +            return 0;
>>> +    }
>>> +
>>> +    return -EINVAL;
>>> +}
>>> +
>>> +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]);
>>> +    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 struct iio_info lidar_info = {
>>> +    .driver_module = THIS_MODULE,
>>> +    .read_raw = lidar_read_raw,
>>> +    .write_raw = lidar_write_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 struct i2c_driver lidar_driver = {
>>> +    .driver = {
>>> +            .name   = LIDAR_DRV_NAME,
>>> +            .owner  = THIS_MODULE,
>>the .owner field is not needed since it is overridden in
>>i2c_register_driver
>>> +    },
>>> +    .probe          = lidar_probe,
>>> +    .remove         = lidar_remove,
>>> +    .id_table       = lidar_id,
>>> +};
>>> +module_i2c_driver(lidar_driver);
>>> +
>>> +MODULE_AUTHOR("Matt Ranostay <mranostay@xxxxxxxxx>");
>>> +MODULE_DESCRIPTION("PulsedLight LIDAR sensor");
>>> +MODULE_LICENSE("GPL");
>>
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>
> --
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