On Fri, 1 Mar 2019, Andreas Klinger wrote:

> Add I2CXL-MaxSonar ultrasonic distance sensors of type family mb12x2 using
> an i2c interface

small comment below
 
> Implemented functionality:
> - reading the distance via in_distance_raw
> - buffered mode with trigger
> - make use of status gpio to announce completion of ranging
> 
> Add mb12x2 driver to Kconfig and Makefile
> 
> Signed-off-by: Andreas Klinger <a...@it-klinger.de>
> ---
>  drivers/iio/proximity/Kconfig  |  11 ++
>  drivers/iio/proximity/Makefile |   1 +
>  drivers/iio/proximity/mb12x2.c | 283 
> +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 295 insertions(+)
>  create mode 100644 drivers/iio/proximity/mb12x2.c
> 
> diff --git a/drivers/iio/proximity/Kconfig b/drivers/iio/proximity/Kconfig
> index b99367a89f81..a420f2cb314b 100644
> --- a/drivers/iio/proximity/Kconfig
> +++ b/drivers/iio/proximity/Kconfig
> @@ -45,6 +45,17 @@ config LIDAR_LITE_V2
>         To compile this driver as a module, choose M here: the
>         module will be called pulsedlight-lite-v2
>  
> +config MB12X2
> +     tristate "MaxSonar MB12X2 family ultrasonic sensors"
> +     depends on I2C
> +     help
> +       Say Y to build a driver for the ultrasonic sensors I2CXL of
> +       MaxBotix which have an i2c interface. It can be used to measure
> +       the distance of objects.
> +
> +       To compile this driver as a module, choose M here: the
> +       module will be called mb12x2.
> +
>  config RFD77402
>       tristate "RFD77402 ToF sensor"
>       depends on I2C
> diff --git a/drivers/iio/proximity/Makefile b/drivers/iio/proximity/Makefile
> index 6d031f903c4c..be9a14db77e7 100644
> --- a/drivers/iio/proximity/Makefile
> +++ b/drivers/iio/proximity/Makefile
> @@ -7,6 +7,7 @@
>  obj-$(CONFIG_AS3935)         += as3935.o
>  obj-$(CONFIG_ISL29501)               += isl29501.o
>  obj-$(CONFIG_LIDAR_LITE_V2)  += pulsedlight-lidar-lite-v2.o
> +obj-$(CONFIG_MB12X2)         += mb12x2.o
>  obj-$(CONFIG_RFD77402)               += rfd77402.o
>  obj-$(CONFIG_SRF04)          += srf04.o
>  obj-$(CONFIG_SRF08)          += srf08.o
> diff --git a/drivers/iio/proximity/mb12x2.c b/drivers/iio/proximity/mb12x2.c
> new file mode 100644
> index 000000000000..8b1ac901c253
> --- /dev/null
> +++ b/drivers/iio/proximity/mb12x2.c
> @@ -0,0 +1,283 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * mb12x2.c - Support for MaxBotix I2CXL-MaxSonar-EZ series ultrasonic
> + *   ranger with i2c interface
> + * actually supported are mb12x2 types
> + *
> + * Copyright (c) 2019 Andreas Klinger <a...@it-klinger.de>
> + *
> + * For details about the device see:
> + * https://www.maxbotix.com/documents/I2CXL-MaxSonar-EZ_Datasheet.pdf
> + *
> + */
> +
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/gpio/consumer.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 MaxSonar device */
> +#define MB12X2_RANGE_COMMAND 0x51    /* Command for reading range */
> +#define MB12X2_ADDR_UNLOCK_1 0xAA    /* Command 1 for changing address */
> +#define MB12X2_ADDR_UNLOCK_2 0xA5    /* Command 2 for changing address */
> +
> +struct mb12x2_data {
> +     struct i2c_client       *client;
> +
> +     struct mutex            lock;
> +
> +     /*
> +      * optionally a gpio can be used to announce when ranging has
> +      * finished
> +      */
> +     struct completion       ranging;
> +     struct gpio_desc        *gpiod_status;
> +     int                     irqnr;
> +
> +     /*
> +      * triggered buffer
> +      * 1x16-bit channel + 3x16 padding + 4x16 timestamp
> +      */
> +     s16                     buffer[8];
> +};
> +
> +static irqreturn_t mb12x2_handle_irq(int irq, void *dev_id)
> +{
> +     struct iio_dev *indio_dev = dev_id;
> +     struct mb12x2_data *data = iio_priv(indio_dev);
> +
> +     /* double check to make sure data is now available */
> +     if (!gpiod_get_value(data->gpiod_status))
> +             complete(&data->ranging);
> +
> +     return IRQ_HANDLED;
> +}
> +
> +static s16 mb12x2_read_distance(struct mb12x2_data *data)
> +{
> +     struct i2c_client *client = data->client;
> +     int ret;
> +     s16 distance;
> +     __be16 buf;
> +
> +     mutex_lock(&data->lock);
> +
> +     reinit_completion(&data->ranging);
> +
> +     ret = i2c_smbus_write_byte(client, MB12X2_RANGE_COMMAND);
> +     if (ret < 0) {
> +             dev_err(&client->dev, "write command - err: %d\n", ret);
> +             mutex_unlock(&data->lock);
> +             return ret;
> +     }
> +
> +     if (data->gpiod_status) {
> +             /* it cannot take more than 100 ms */
> +             ret = wait_for_completion_killable_timeout(&data->ranging,
> +                                                                     HZ/10);
> +             if (ret < 0) {
> +                     mutex_unlock(&data->lock);
> +                     return ret;
> +             } else if (ret == 0) {
> +                     mutex_unlock(&data->lock);
> +                     return -ETIMEDOUT;
> +             }
> +     } else {
> +             /*
> +              * use simple sleep if gpio announce pin is not connected
> +              */
> +             msleep(15);
> +     }
> +
> +     ret = i2c_master_recv(client, (char *)&buf, sizeof(buf));
> +     if (ret < 0) {
> +             dev_err(&client->dev, "i2c_master_recv: ret=%d\n", ret);
> +             mutex_unlock(&data->lock);
> +             return ret;
> +     }
> +
> +     distance = __be16_to_cpu(buf);
> +     /* check for not returning misleading error codes */
> +     if (distance < 0) {
> +             dev_err(&client->dev, "distance=%d\n", distance);

mutex_unlock() missing, the unlock could be done right after 
i2c_master_recv()

> +             return -EINVAL;
> +     }
> +
> +     mutex_unlock(&data->lock);
> +
> +     return distance;
> +}
> +
> +static irqreturn_t mb12x2_trigger_handler(int irq, void *p)
> +{
> +     struct iio_poll_func *pf = p;
> +     struct iio_dev *indio_dev = pf->indio_dev;
> +     struct mb12x2_data *data = iio_priv(indio_dev);
> +     s16 sensor_data;
> +
> +     sensor_data = mb12x2_read_distance(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 mb12x2_read_raw(struct iio_dev *indio_dev,
> +                         struct iio_chan_spec const *channel, int *val,
> +                         int *val2, long mask)
> +{
> +     struct mb12x2_data *data = iio_priv(indio_dev);
> +     int ret;
> +
> +     if (channel->type != IIO_DISTANCE)
> +             return -EINVAL;
> +
> +     switch (mask) {
> +     case IIO_CHAN_INFO_RAW:
> +             ret = mb12x2_read_distance(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 const struct iio_chan_spec mb12x2_channels[] = {
> +     {
> +             .type = IIO_DISTANCE,
> +             .info_mask_separate =
> +                             BIT(IIO_CHAN_INFO_RAW) |
> +                             BIT(IIO_CHAN_INFO_SCALE),
> +             .scan_index = 0,
> +             .scan_type = {
> +                     .sign = 's',
> +                     .realbits = 16,
> +                     .storagebits = 16,
> +                     .endianness = IIO_CPU,
> +             },
> +     },
> +     IIO_CHAN_SOFT_TIMESTAMP(1),
> +};
> +
> +static const struct iio_info mb12x2_info = {
> +     .read_raw = mb12x2_read_raw,
> +};
> +
> +static int mb12x2_probe(struct i2c_client *client,
> +                                      const struct i2c_device_id *id)
> +{
> +     struct iio_dev *indio_dev;
> +     struct mb12x2_data *data;
> +     int ret;
> +     struct device *dev = &client->dev;
> +
> +     if (!i2c_check_functionality(client->adapter,
> +                                     I2C_FUNC_SMBUS_READ_BYTE |
> +                                     I2C_FUNC_SMBUS_WRITE_BYTE))
> +             return -ENODEV;
> +
> +     indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
> +     if (!indio_dev)
> +             return -ENOMEM;
> +
> +     data = iio_priv(indio_dev);
> +     i2c_set_clientdata(client, indio_dev);
> +     data->client = client;
> +
> +     indio_dev->info = &mb12x2_info;
> +     indio_dev->name = id->name;
> +     indio_dev->dev.parent = dev;
> +     indio_dev->modes = INDIO_DIRECT_MODE;
> +     indio_dev->channels = mb12x2_channels;
> +     indio_dev->num_channels = ARRAY_SIZE(mb12x2_channels);
> +
> +     mutex_init(&data->lock);
> +
> +     init_completion(&data->ranging);
> +
> +     data->gpiod_status = devm_gpiod_get(dev, "status", GPIOD_IN);
> +     if (IS_ERR(data->gpiod_status)) {
> +             if (PTR_ERR(data->gpiod_status) == -ENOENT) {
> +                     dev_warn(dev, "no status gpio --> use sleep instead\n");
> +                     data->gpiod_status = NULL;
> +             } else {
> +                     dev_err(dev, "cannot setup gpio; err=%ld\n",
> +                                     PTR_ERR(data->gpiod_status));
> +                     return PTR_ERR(data->gpiod_status);
> +             }
> +     }
> +
> +     if (data->gpiod_status) {
> +             data->irqnr = gpiod_to_irq(data->gpiod_status);
> +             if (data->irqnr < 0) {
> +                     dev_err(dev, "gpiod_to_irq: %d\n", data->irqnr);
> +                     return data->irqnr;
> +             }
> +
> +             ret = devm_request_irq(dev, data->irqnr, mb12x2_handle_irq,
> +                             IRQF_TRIGGER_FALLING, id->name, indio_dev);
> +             if (ret < 0) {
> +                     dev_err(dev, "request_irq: %d\n", ret);
> +                     return ret;
> +             }
> +     }
> +
> +     ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
> +                     iio_pollfunc_store_time, mb12x2_trigger_handler, NULL);
> +     if (ret < 0) {
> +             dev_err(dev, "setup of iio triggered buffer failed\n");
> +             return ret;
> +     }
> +
> +     return devm_iio_device_register(dev, indio_dev);
> +}
> +
> +static const struct of_device_id of_mb12x2_match[] = {
> +     { .compatible = "maxbotix,i2cxl", },
> +     {},
> +};
> +
> +MODULE_DEVICE_TABLE(of, of_mb12x2_match);
> +
> +static const struct i2c_device_id mb12x2_id[] = {
> +     { "maxbotix-i2cxl", },
> +     { }
> +};
> +MODULE_DEVICE_TABLE(i2c, mb12x2_id);
> +
> +static struct i2c_driver mb12x2_driver = {
> +     .driver = {
> +             .name   = "maxbotix-i2cxl",
> +             .of_match_table = of_mb12x2_match,
> +     },
> +     .probe = mb12x2_probe,
> +     .id_table = mb12x2_id,
> +};
> +module_i2c_driver(mb12x2_driver);
> +
> +MODULE_AUTHOR("Andreas Klinger <a...@it-klinger.de>");
> +MODULE_DESCRIPTION("Maxbotix I2CXL-MaxSonar i2c ultrasonic ranger driver");
> +MODULE_LICENSE("GPL");
> 

-- 

Peter Meerwald-Stadler
Mobile: +43 664 24 44 418

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