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From:   Puranjay Mohan <puranjay12@gmail.com>
Date:   Mon, 9 Aug 2021 13:16:58 +0530
Message-ID: <CANk7y0gXwMPqAXDTcB-w9MiM=fwjQrSWauXnw9G-V2QohF=CAg@mail.gmail.com>
Subject: Re: [PATCH v9 2/2] iio: accel: adxl355: Add triggered buffer support
To:     "Hennerich, Michael" <Michael.Hennerich@analog.com>,
        Jonathan Cameron <jic23@kernel.org>,
        devicetree <devicetree@vger.kernel.org>,
        linux-iio <linux-iio@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Lars-Peter Clausen <lars@metafoo.de>,
        "Bogdan, Dragos" <Dragos.Bogdan@analog.com>,
        "Berghe, Darius" <Darius.Berghe@analog.com>
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Please ignore this patch.
It was sent by mistake, it is not supposed to be a part of this series.

On Mon, Aug 9, 2021 at 1:15 PM Puranjay Mohan <puranjay12@gmail.com> wrote:
>
> Provide a way for continuous data capture by setting up buffer support. The
> data ready signal exposed at the DRDY pin of the ADXL355 is exploited as
> a hardware interrupt which triggers to fill the buffer.
>
> Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
> ---
>  drivers/iio/accel/Kconfig        |   4 ++
>  drivers/iio/accel/adxl355.h      |   2 +-
>  drivers/iio/accel/adxl355_core.c | 102 ++++++++++++++++++++++++++++++-
>  drivers/iio/accel/adxl355_i2c.c  |   3 +-
>  drivers/iio/accel/adxl355_spi.c  |   2 +-
>  5 files changed, 108 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
> index d0c45c809..9c16c1841 100644
> --- a/drivers/iio/accel/Kconfig
> +++ b/drivers/iio/accel/Kconfig
> @@ -69,6 +69,8 @@ config ADXL355_I2C
>         depends on I2C
>         select ADXL355
>         select REGMAP_I2C
> +       select IIO_BUFFER
> +       select IIO_TRIGGERED_BUFFER
>         help
>           Say Y here if you want to build i2c support for the Analog Devices
>           ADXL355 3-axis digital accelerometer.
> @@ -82,6 +84,8 @@ config ADXL355_SPI
>         depends on SPI
>         select ADXL355
>         select REGMAP_SPI
> +       select IIO_BUFFER
> +       select IIO_TRIGGERED_BUFFER
>         help
>           Say Y here if you want to build spi support for the Analog Devices
>           ADXL355 3-axis digital accelerometer.
> diff --git a/drivers/iio/accel/adxl355.h b/drivers/iio/accel/adxl355.h
> index 322b0abb8..f0a376e6d 100644
> --- a/drivers/iio/accel/adxl355.h
> +++ b/drivers/iio/accel/adxl355.h
> @@ -15,5 +15,5 @@ extern const struct regmap_access_table adxl355_readable_regs_tbl;
>  extern const struct regmap_access_table adxl355_writeable_regs_tbl;
>
>  int adxl355_core_probe(struct device *dev, struct regmap *regmap,
> -                      const char *name);
> +                      const char *name, int irq);
>  #endif /* _ADXL355_H_ */
> diff --git a/drivers/iio/accel/adxl355_core.c b/drivers/iio/accel/adxl355_core.c
> index d1163cde1..45397dcce 100644
> --- a/drivers/iio/accel/adxl355_core.c
> +++ b/drivers/iio/accel/adxl355_core.c
> @@ -9,6 +9,10 @@
>
>  #include <asm/unaligned.h>
>  #include <linux/bitfield.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/trigger.h>
> +#include <linux/iio/triggered_buffer.h>
> +#include <linux/iio/trigger_consumer.h>
>  #include <linux/iio/iio.h>
>  #include <linux/limits.h>
>  #include <linux/math64.h>
> @@ -153,6 +157,7 @@ static const struct adxl355_chan_info adxl355_chans[] = {
>  };
>
>  struct adxl355_data {
> +       int irq;
>         struct regmap *regmap;
>         struct device *dev;
>         struct mutex lock; /* lock to protect op_mode */
> @@ -162,6 +167,12 @@ struct adxl355_data {
>         int calibbias[3];
>         int adxl355_hpf_3db_table[7][2];
>         u8 transf_buf[3] ____cacheline_aligned;
> +       struct iio_trigger      *dready_trig;
> +       /* Ensure correct alignment of timestamp when present */
> +       struct {
> +               __be32 channels[3];
> +               s64 ts;
> +       } buffer ____cacheline_aligned;
>  };
>
>  static int adxl355_set_op_mode(struct adxl355_data *data,
> @@ -493,12 +504,46 @@ static int adxl355_read_avail(struct iio_dev *indio_dev,
>         }
>  }
>
> +static const unsigned long adxl355_avail_scan_masks[] = {
> +       GENMASK(3, 0),
> +       0
> +};
> +
>  static const struct iio_info adxl355_info = {
>         .read_raw       = adxl355_read_raw,
>         .write_raw      = adxl355_write_raw,
>         .read_avail     = &adxl355_read_avail
>  };
>
> +static const struct iio_trigger_ops adxl355_trigger_ops = {
> +       .validate_device = &iio_trigger_validate_own_device,
> +};
> +
> +static irqreturn_t adxl355_trigger_handler(int irq, void *p)
> +{
> +       struct iio_poll_func *pf = p;
> +       struct iio_dev *indio_dev = pf->indio_dev;
> +       struct adxl355_data *data = iio_priv(indio_dev);
> +       int ret;
> +
> +       mutex_lock(&data->lock);
> +
> +       ret = regmap_bulk_read(data->regmap, ADXL355_XDATA3_REG,
> +                              data->buffer.channels,
> +                              9);
> +       if (ret)
> +               goto out_unlock_notify;
> +
> +       iio_push_to_buffers_with_timestamp(indio_dev, &data->buffer,
> +                                          pf->timestamp);
> +
> +out_unlock_notify:
> +       mutex_unlock(&data->lock);
> +       iio_trigger_notify_done(indio_dev->trig);
> +
> +       return IRQ_HANDLED;
> +}
> +
>  #define ADXL355_ACCEL_CHANNEL(index, reg, axis) {                      \
>         .type = IIO_ACCEL,                                              \
>         .address = reg,                                                 \
> @@ -512,6 +557,7 @@ static const struct iio_info adxl355_info = {
>         .info_mask_shared_by_type_available =                           \
>                 BIT(IIO_CHAN_INFO_SAMP_FREQ) |                          \
>                 BIT(IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY),      \
> +       .scan_index = index,                                            \
>         .scan_type = {                                                  \
>                 .sign = 's',                                            \
>                 .realbits = 20,                                         \
> @@ -531,17 +577,56 @@ static const struct iio_chan_spec adxl355_channels[] = {
>                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
>                                       BIT(IIO_CHAN_INFO_SCALE) |
>                                       BIT(IIO_CHAN_INFO_OFFSET),
> +               .scan_index = 3,
>                 .scan_type = {
>                         .sign = 's',
>                         .realbits = 12,
>                         .storagebits = 16,
>                         .endianness = IIO_BE,
>                 },
> -       }
> +       },
> +       IIO_CHAN_SOFT_TIMESTAMP(4)
>  };
>
> +static int adxl355_probe_trigger(struct iio_dev *indio_dev)
> +{
> +       struct adxl355_data *data = iio_priv(indio_dev);
> +       int ret;
> +
> +       if (!data->irq) {
> +               dev_info(data->dev, "no irq, using polling\n");
> +               return 0;
> +       }
> +
> +       data->dready_trig = devm_iio_trigger_alloc(data->dev, "%s-dev%d",
> +                                                  indio_dev->name,
> +                                                  indio_dev->id);
> +       if (!data->dready_trig)
> +               return -ENOMEM;
> +
> +       data->dready_trig->ops = &adxl355_trigger_ops;
> +       iio_trigger_set_drvdata(data->dready_trig, indio_dev);
> +
> +       ret = devm_request_irq(data->dev, data->irq,
> +                              &iio_trigger_generic_data_rdy_poll,
> +                              IRQF_ONESHOT, "adxl355_irq", data->dready_trig);
> +       if (ret < 0)
> +               return dev_err_probe(data->dev, ret, "request irq %d failed\n",
> +                                    data->irq);
> +
> +       ret = devm_iio_trigger_register(data->dev, data->dready_trig);
> +       if (ret) {
> +               dev_err(data->dev, "iio trigger register failed\n");
> +               return ret;
> +       }
> +
> +       indio_dev->trig = iio_trigger_get(data->dready_trig);
> +
> +       return 0;
> +}
> +
>  int adxl355_core_probe(struct device *dev, struct regmap *regmap,
> -                      const char *name)
> +                      const char *name, int irq)
>  {
>         struct adxl355_data *data;
>         struct iio_dev *indio_dev;
> @@ -554,6 +639,7 @@ int adxl355_core_probe(struct device *dev, struct regmap *regmap,
>         data = iio_priv(indio_dev);
>         data->regmap = regmap;
>         data->dev = dev;
> +       data->irq = irq;
>         data->op_mode = ADXL355_STANDBY;
>         mutex_init(&data->lock);
>
> @@ -562,6 +648,7 @@ int adxl355_core_probe(struct device *dev, struct regmap *regmap,
>         indio_dev->modes = INDIO_DIRECT_MODE;
>         indio_dev->channels = adxl355_channels;
>         indio_dev->num_channels = ARRAY_SIZE(adxl355_channels);
> +       indio_dev->available_scan_masks = adxl355_avail_scan_masks;
>
>         ret = adxl355_setup(data);
>         if (ret < 0) {
> @@ -569,6 +656,17 @@ int adxl355_core_probe(struct device *dev, struct regmap *regmap,
>                 return ret;
>         }
>
> +       ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
> +                                             &iio_pollfunc_store_time,
> +                                             &adxl355_trigger_handler, NULL);
> +       if (ret < 0)
> +               return dev_err_probe(dev, ret,
> +                                    "iio triggered buffer setup failed\n");
> +
> +       ret = adxl355_probe_trigger(indio_dev);
> +       if (ret < 0)
> +               return ret;
> +
>         return devm_iio_device_register(dev, indio_dev);
>  }
>  EXPORT_SYMBOL_GPL(adxl355_core_probe);
> diff --git a/drivers/iio/accel/adxl355_i2c.c b/drivers/iio/accel/adxl355_i2c.c
> index e3070ee81..c18521819 100644
> --- a/drivers/iio/accel/adxl355_i2c.c
> +++ b/drivers/iio/accel/adxl355_i2c.c
> @@ -31,7 +31,8 @@ static int adxl355_i2c_probe(struct i2c_client *client)
>                 return PTR_ERR(regmap);
>         }
>
> -       return adxl355_core_probe(&client->dev, regmap, client->name);
> +       return adxl355_core_probe(&client->dev, regmap, client->name,
> +                                 client->irq);
>  }
>
>  static const struct i2c_device_id adxl355_i2c_id[] = {
> diff --git a/drivers/iio/accel/adxl355_spi.c b/drivers/iio/accel/adxl355_spi.c
> index a16bd1407..f9ba153f6 100644
> --- a/drivers/iio/accel/adxl355_spi.c
> +++ b/drivers/iio/accel/adxl355_spi.c
> @@ -34,7 +34,7 @@ static int adxl355_spi_probe(struct spi_device *spi)
>                 return PTR_ERR(regmap);
>         }
>
> -       return adxl355_core_probe(&spi->dev, regmap, id->name);
> +       return adxl355_core_probe(&spi->dev, regmap, id->name, spi->irq);
>  }
>
>  static const struct spi_device_id adxl355_spi_id[] = {
> --
> 2.30.1
>


-- 
Thanks and Regards

Yours Truly,

Puranjay Mohan