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SubjectRe: [PATCH v2 3/4] mb12x2.c: add distance iio sensor with i2c
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 <ak@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 <ak@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 <ak@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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