Hi Song,

On Tue, Sep 11, 2018 at 03:53:57PM +0800, Song Qiang wrote:
> This driver was originally written by ST in 2016 as a misc input device
> driver, and hasn't been maintained for a long time. I grabbed some code
> from it's API and reformed it into a iio proximity device driver.
> This version of driver uses i2c bus to talk to the sensor and
> polling for measuring completes, so no irq line is needed.
> This version of driver supports only one-shot mode, and it can be
> tested with reading from
> /sys/bus/iio/devices/iio:deviceX/in_distance_raw
> 
> Signed-off-by: Song Qiang <songqiang.1304...@gmail.com>
> ---
>  .../bindings/iio/proximity/vl53l0x.txt        |  12 ++
>  drivers/iio/proximity/Kconfig                 |  11 +
>  drivers/iio/proximity/Makefile                |   2 +
>  drivers/iio/proximity/vl53l0x-i2c.c           | 196 ++++++++++++++++++
>  4 files changed, 221 insertions(+)
>  create mode 100644 
> Documentation/devicetree/bindings/iio/proximity/vl53l0x.txt
>  create mode 100644 drivers/iio/proximity/vl53l0x-i2c.c
> 
> diff --git a/Documentation/devicetree/bindings/iio/proximity/vl53l0x.txt 
> b/Documentation/devicetree/bindings/iio/proximity/vl53l0x.txt
> new file mode 100644
> index 000000000000..64b69442f08e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/proximity/vl53l0x.txt
> @@ -0,0 +1,12 @@
> +ST's VL53L0X ToF ranging sensor
> +
> +Required properties:
> +     - compatible: must be "st,vl53l0x-i2c"
> +     - reg: i2c address where to find the device
> +
> +Example:
> +
> +vl53l0x@29 {
> +     compatible = "st,vl53l0x-i2c";
> +     reg = <0x29>;
> +};
> diff --git a/drivers/iio/proximity/Kconfig b/drivers/iio/proximity/Kconfig
> index f726f9427602..5f421cbd37f3 100644
> --- a/drivers/iio/proximity/Kconfig
> +++ b/drivers/iio/proximity/Kconfig
> @@ -79,4 +79,15 @@ config SRF08
>         To compile this driver as a module, choose M here: the
>         module will be called srf08.
>  
> +config VL53L0X_I2C
> +     tristate "STMicroelectronics VL53L0X ToF ranger sensor (I2C)"
> +     depends on I2C
> +     help
> +       Say Y here to build a driver for STMicroelectronics VL53L0X
> +       ToF ranger sensors with i2c interface.
> +       This driver can be used to measure the distance of objects.
> +
> +       To compile this driver as a module, choose M here: the
> +       module will be called vl53l0x-i2c.
> +
>  endmenu
> diff --git a/drivers/iio/proximity/Makefile b/drivers/iio/proximity/Makefile
> index 4f4ed45e87ef..dedfb5bf3475 100644
> --- a/drivers/iio/proximity/Makefile
> +++ b/drivers/iio/proximity/Makefile
> @@ -10,3 +10,5 @@ obj-$(CONFIG_RFD77402)              += rfd77402.o
>  obj-$(CONFIG_SRF04)          += srf04.o
>  obj-$(CONFIG_SRF08)          += srf08.o
>  obj-$(CONFIG_SX9500)         += sx9500.o
> +obj-$(CONFIG_VL53L0X_I2C)    += vl53l0x-i2c.o
> +
> diff --git a/drivers/iio/proximity/vl53l0x-i2c.c 
> b/drivers/iio/proximity/vl53l0x-i2c.c
> new file mode 100644
> index 000000000000..4eac40353494
> --- /dev/null
> +++ b/drivers/iio/proximity/vl53l0x-i2c.c
> @@ -0,0 +1,196 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + *  Support for ST's VL53L0X FlightSense ToF Ranger Sensor on a i2c bus.
> + *
> + *  Copyright (C) 2018 Song Qiang <songqiang.1304...@gmail.com>
> + *

Andy suggested to remove this emty line and not ST copyright.

So, be careful or .... "Better Call Saul" ;)

> +
> +#include <linux/delay.h>
> +#include <linux/i2c.h>
> +#include <linux/iio/iio.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +
> +#define VL53L0X_DRV_NAME                             "vl53l0x-i2c"
> +
> +#define VL_REG_SYSRANGE_START                                0x00
> +#define VL_REG_SYSRANGE_MODE_MASK                    GENMASK(3, 0)
> +#define VL_REG_SYSRANGE_MODE_START_STOP                      BIT(0)
> +#define VL_REG_SYSRANGE_MODE_SINGLESHOT                      0x00
> +#define VL_REG_SYSRANGE_MODE_BACKTOBACK                      BIT(1)
> +#define VL_REG_SYSRANGE_MODE_TIMED                   BIT(2)
> +#define VL_REG_SYSRANGE_MODE_HISTOGRAM                       BIT(3)
> +
> +#define VL_REG_SYS_SEQUENCE_CFG                              BIT(0)
> +#define VL_REG_SYS_RANGE_CFG                         0x09
> +#define VL_REG_SYS_INTERMEASUREMENT_PERIOD           BIT(2)
> +
> +#define VL_REG_SYS_INT_CFG_GPIO                              0x0A
> +#define VL_REG_SYS_INT_GPIO_DISABLED                 0x00
> +#define VL_REG_SYS_INT_GPIO_LEVEL_LOW                        BIT(0)
> +#define VL_REG_SYS_INT_GPIO_LEVEL_HIGH                       BIT(1)
> +#define VL_REG_SYS_INT_GPIO_NEW_SAMPLE_READY         BIT(2)
> +#define VL_REG_SYS_INT_GPIO_OUT_OF_WINDOW            0x03
> +#define VL_REG_GPIO_HV_MUX_ACTIVE_HIGH                       0x84
> +#define VL_REG_SYS_INT_CLEAR                         0x0B
> +
> +#define VL_REG_RESULT_INT_STATUS                     0x13
> +#define VL_REG_RESULT_RANGE_STATUS                   0x14
> +#define VL_REG_RESULT_RANGE_SATTUS_COMPLETE          BIT(0)
> +
> +#define VL_REG_I2C_SLAVE_DEVICE_ADDRESS                      0x8a
> +
> +#define VL_REG_IDENTIFICATION_MODEL_ID                       0xc0
> +#define VL_REG_IDENTIFICATION_REVISION_ID            0xc2
> +
> +struct vl53l0x_data {
> +     struct i2c_client *client;
> +     struct iio_dev *indio_dev;

This is not required in this private struct.
Not sure though...

> +};
> +
> +static int vl53l0x_read_proximity(struct vl53l0x_data *data,
> +                               const struct iio_chan_spec *chan,
> +                               int *val)
> +{
> +     u8 write_command = VL_REG_RESULT_RANGE_STATUS;
> +     struct i2c_client *client = data->client;
> +     unsigned int tries = 20;
> +     struct i2c_msg msg[2];
> +     u8 buffer[12];
> +     int ret;
> +
> +     ret = i2c_smbus_write_byte_data(data->client,
> +                                     VL_REG_SYSRANGE_START, 1);
> +     if (ret < 0)
> +             return ret;
> +
> +     do {
> +             ret = i2c_smbus_read_byte_data(data->client,
> +                                            VL_REG_RESULT_RANGE_STATUS);
> +             if (ret < 0)
> +                     return ret;
> +
> +             if (ret & VL_REG_RESULT_RANGE_SATTUS_COMPLETE)
> +                     break;
> +
> +             usleep_range(1000, 5000);
> +     } while (tries--);
> +     if (!tries)
> +             return -ETIMEDOUT;
> +
> +     msg[0].addr = client->addr;
> +     msg[0].buf = &write_command;
> +     msg[0].len = 1;
> +     msg[0].flags = client->flags | I2C_M_STOP;
> +
> +     msg[1].addr = client->addr;
> +     msg[1].buf = buffer;
> +     msg[1].len = 12;
> +     msg[1].flags = client->flags | I2C_M_RD;
> +
> +     ret = i2c_transfer(client->adapter, msg, 2);
> +     if (ret < 0)
> +             return ret;
> +     else if (ret != 2)
> +             dev_err(&data->client->dev, "vl53l0x: consecutively read error. 
> ");
> +
> +     *val = __le16_to_cpu((buffer[10] << 8) + buffer[11]);

IIRC  __le/be _* shouldn't be directly used and instead use
le16_to_cpu(). Let it decide the byte order unwrapping to
be done.

> +     return 0;
> +}
> +
> +static const struct iio_chan_spec vl53l0x_channels[] = {
> +     {
> +             .type = IIO_DISTANCE,
> +             .info_mask_separate = BIT(IIO_CHAN_INFO_RAW)
> +     },
> +     IIO_CHAN_SOFT_TIMESTAMP(1),
> +};
> +
> +static int vl53l0x_read_raw(struct iio_dev *indio_dev,
> +                         const struct iio_chan_spec *chan,
> +                         int *val, int *val2, long mask)
> +{
> +     struct vl53l0x_data *data = iio_priv(indio_dev);
> +     int ret;
> +
> +     if (chan->type != IIO_DISTANCE) {
> +             dev_err(&data->client->dev, "vl53l0x: iio type error");
> +             return -EINVAL;
> +     }
> +
> +     switch (mask) {
> +     case IIO_CHAN_INFO_RAW:
> +             ret = iio_device_claim_direct_mode(indio_dev);

You don't have any other buffer/trigger support for now and I believe
there is no need to claim direct mode.

> +             if (ret)
> +                     return ret;
> +             ret = vl53l0x_read_proximity(data, chan, val);
> +             if (ret < 0)
> +                     dev_err(&data->client->dev,
> +                             "vl53l0x: raw value read error with %d", ret);
> +
> +             ret = IIO_VAL_INT;
> +             iio_device_release_direct_mode(indio_dev);
> +             return ret;
> +     default:
> +             dev_err(&data->client->dev, "vl53l0x: IIO_CHAN_* not 
> recognzed.");
> +             return -EINVAL;
> +     }
> +}
> +
> +static const struct iio_info vl53l0x_info = {
> +     .read_raw = vl53l0x_read_raw,
> +};
> +
> +static int vl53l0x_probe(struct i2c_client *client)
> +{
> +     struct vl53l0x_data *data;
> +     struct iio_dev *indio_dev;
> +     int ret;
> +
> +     indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
> +     if (!indio_dev)
> +             return -ENOMEM;
> +
> +     data = iio_priv(indio_dev);
> +     data->client = client;
> +     data->indio_dev = indio_dev;

Is this required ?

> +     i2c_set_clientdata(client, indio_dev);
> +
> +     if (!i2c_check_functionality(client->adapter,
> +                                  I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_I2C))
> +             return -EOPNOTSUPP;
> +
> +     indio_dev->dev.parent = &client->dev;
> +     indio_dev->name = VL53L0X_DRV_NAME;
> +     indio_dev->info = &vl53l0x_info;
> +     indio_dev->channels = vl53l0x_channels;
> +     indio_dev->num_channels = ARRAY_SIZE(vl53l0x_channels);
> +     indio_dev->modes = INDIO_DIRECT_MODE;
> +
> +     ret = devm_iio_device_register(&client->dev, indio_dev);

        return devm_iio_device_register(&client->dev, indio_dev);

> +     if (ret)
> +             return ret;
> +
> +     return 0;
> +}

Do you have the sensor and are these patches tested ?
Just curious!

Thanks
-- 
Himanshu Jha
Undergraduate Student
Department of Electronics & Communication
Guru Tegh Bahadur Institute of Technology

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