On Sun, Aug 16, 2015 at 1:24 AM, Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
> On 12/08/15 07:01, 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 <mranostay@xxxxxxxxx>
> You missed a few cases of the name lidar being used for device
> matching.
>
> Also, just noticed you are holding a local lock only when checking if
> bufferred capture is enabled. You need to hold the indio_dev->mlock to
> avoid racing with a buffer enable.
>
> Mostly there now though.
>
> Jonathan
>> ---
>> drivers/iio/proximity/Kconfig | 12 +
>> drivers/iio/proximity/Makefile | 1 +
>> drivers/iio/proximity/pulsedlight-lidar-lite-v2.c | 292 ++++++++++++++++++++++
>> 3 files changed, 305 insertions(+)
>> create mode 100644 drivers/iio/proximity/pulsedlight-lidar-lite-v2.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
> The config symbol needs more detail as well as it's not a unique
> part number.
>> + 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.
> Not any more it won't.
>> +
>> config SX9500
>> tristate "SX9500 Semtech proximity sensor"
>> select IIO_BUFFER
>> diff --git a/drivers/iio/proximity/Makefile b/drivers/iio/proximity/Makefile
>> index 9818dc5..081ae33 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) += pulsedlight-lidar-lite-v2.o
>> obj-$(CONFIG_SX9500) += sx9500.o
>> diff --git a/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c b/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c
>> new file mode 100644
>> index 0000000..ff0681b
>> --- /dev/null
>> +++ b/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c
>> @@ -0,0 +1,292 @@
>> +/*
>> + * pulsedlight-lidar-lite-v2.c - Support for PulsedLight LIDAR 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
>> + *
> No blank line here.
>> + */
>> +
>> +#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;
>> +
>> + /*
>> + * Device needs a STOP condition between address write, and data read
>> + * so in turn i2c_smbus_read_byte_data cannot be used
>> + */
>> +
>> + 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;
>> +}
>> +
>> +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;
>> + *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);
>> +
>
> This particular check needs to hold the indio_dev->mlock as that
> is the one that protects core state changes (enabling and disabling the
> buffer). You want to hang on to that lock until the read is done.
So I guess I can get rid of the data->lock? Since it really isn't used
anywhere else?
>
>> + 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);
>> + 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},
>
> This one wants a longer name as well. It's afterall used for
> matching in some circumstances.
>
>> + { },
>> +};
>> +MODULE_DEVICE_TABLE(i2c, lidar_id);
>> +
>> +static const struct of_device_id lidar_dt_ids[] = {
>> + { .compatible = "pulsedlight,lidar-lite-v2" },
>> + { }
>> +};
>> +
>> +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 <mranostay@xxxxxxxxx>");
>> +MODULE_DESCRIPTION("PulsedLight LIDAR sensor");
>> +MODULE_LICENSE("GPL");
>>
>
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