On 1 August 2015 09:39:11 BST, Vladimir Barinov 
<vladimir.bari...@cogentembedded.com> 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 <mranos...@gmail.com>
>> ---
>>   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.

>>   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.

>> +    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 <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/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 <mranos...@gmail.com>");
>> +MODULE_DESCRIPTION("PulsedLight LIDAR sensor");
>> +MODULE_LICENSE("GPL");
>
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