RE: [PATCH V1 1/1] iio: accel: sca3300: Extend the trigger buffer from 16 to 32 bytes

[LI Qingwu <qing-wu.li@leica-geosystems.com.cn>]

> -----Original Message-----
> From: Jonathan Cameron <jic23@kernel.org>
> Sent: Saturday, July 2, 2022 12:46 AM
> To: LI Qingwu <Qing-wu.Li@leica-geosystems.com.cn>
> Cc: lars@metafoo.de; tomas.melin@vaisala.com; nuno.sa@analog.com;
> linux-iio@vger.kernel.org; linux-kernel@vger.kernel.org;
> GEO-CHHER-bsp-development <bsp-development.geo@leica-geosystems.com>
> Subject: Re: [PATCH V1 1/1] iio: accel: sca3300: Extend the trigger buffer from
> 16 to 32 bytes
> 
> [Some people who received this message don't often get email from
> jic23@kernel.org. Learn why this is important at
> https://aka.ms/LearnAboutSenderIdentification ]
> 
> This email is not from Hexagon's Office 365 instance. Please be careful while
> clicking links, opening attachments, or replying to this email.
> 
> 
> On Fri,  1 Jul 2022 02:30:30 +0000
> LI Qingwu <Qing-wu.Li@leica-geosystems.com.cn> wrote:
> 
> > After added inclination angle channels, the trigger buffer size is
> > insufficient. Extend the buffer size from 16 to 32 bytes, and change
> > the trigger buffer from the struct to a u8 array to adapt the sensor
> > with/without inclination angles output.
> > New trigger buffer data:
> >   - SCA3300: 3 accel channels, temp, and timestamp.
> >   - SCL3300: 3 accel channels, temp, 3 incli channels, and timestamp.
> > Readjustment the scan index to make it consistent with the buffer data.
> >
> > Signed-off-by: LI Qingwu <Qing-wu.Li@leica-geosystems.com.cn>
> 
> Hi.
> 
> Looks good. A trivial suggestion inline to make the code a little more 'self
> documenting'.  It's a minor change so if you are happy with the suggestion I
> can tweak that whilst applying.
> 
> Thanks,
> 
> Jonathan
> 

Yes, sure, absolutely agree, Thank you!

LI Qingwu

> > ---
> >  drivers/iio/accel/sca3300.c | 29 ++++++++++++++++++-----------
> >  1 file changed, 18 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/iio/accel/sca3300.c b/drivers/iio/accel/sca3300.c
> > index 3c4827bfef53..820dfb635bf1 100644
> > --- a/drivers/iio/accel/sca3300.c
> > +++ b/drivers/iio/accel/sca3300.c
> > @@ -47,12 +47,20 @@
> >  #define SCL3300_REG_ANG_CTRL 0x0C
> >  #define SCL3300_ANG_ENABLE   0x1F
> >
> > +/*
> > + * Buffer size max case:
> > + * Three accel channels, two bytes per channel.
> > + * Temperature channel, two bytes.
> > + * Three incli channels, two bytes per channel.
> > + * Timestamp channel, eight bytes.
> > + */
> > +#define SCA3300_MAX_BUFFER_SIZE (ALIGN(2 * 7, sizeof(s64)) +
> > +sizeof(s64))
> 
> Instead of the 2 use sizeof(s16)
>  Also now you don't have timestamp in your enum sca3000_scan_indexes you
> could add a 'tail' element to the enum such as SCA3000_SCAN_MAX then use
> that instead of the 7 here.  Hopefully that would make this more self
> documenting.


> 
> > +
> >  enum sca3300_scan_indexes {
> >       SCA3300_ACC_X = 0,
> >       SCA3300_ACC_Y,
> >       SCA3300_ACC_Z,
> >       SCA3300_TEMP,
> > -     SCA3300_TIMESTAMP,
> >       SCA3300_INCLI_X,
> >       SCA3300_INCLI_Y,
> >       SCA3300_INCLI_Z,
> > @@ -140,10 +148,10 @@ static const struct iio_chan_spec scl3300_channels[]
> = {
> >       SCA3300_ACCEL_CHANNEL(SCA3300_ACC_Y, 0x2, Y),
> >       SCA3300_ACCEL_CHANNEL(SCA3300_ACC_Z, 0x3, Z),
> >       SCA3300_TEMP_CHANNEL(SCA3300_TEMP, 0x05),
> > -     IIO_CHAN_SOFT_TIMESTAMP(4),
> >       SCA3300_INCLI_CHANNEL(SCA3300_INCLI_X, 0x09, X),
> >       SCA3300_INCLI_CHANNEL(SCA3300_INCLI_Y, 0x0A, Y),
> >       SCA3300_INCLI_CHANNEL(SCA3300_INCLI_Z, 0x0B, Z),
> > +     IIO_CHAN_SOFT_TIMESTAMP(7),
> >  };
> >
> >  static const unsigned long sca3300_scan_masks[] = { @@ -184,7 +192,9
> > @@ struct sca3300_chip_info {
> >   * @spi: SPI device structure
> >   * @lock: Data buffer lock
> >   * @chip: Sensor chip specific information
> > - * @scan: Triggered buffer. Four channel 16-bit data + 64-bit
> > timestamp
> > + * @buffer: Triggered buffer:
> > + *          -SCA3300: 4 channel 16-bit data + 64-bit timestamp
> > + *          -SCL3300: 7 channel 16-bit data + 64-bit timestamp
> >   * @txbuf: Transmit buffer
> >   * @rxbuf: Receive buffer
> >   */
> > @@ -192,10 +202,7 @@ struct sca3300_data {
> >       struct spi_device *spi;
> >       struct mutex lock;
> >       const struct sca3300_chip_info *chip;
> > -     struct {
> > -             s16 channels[4];
> > -             s64 ts __aligned(sizeof(s64));
> > -     } scan;
> > +     u8 buffer[SCA3300_MAX_BUFFER_SIZE] __aligned(sizeof(s64));
> >       u8 txbuf[4] __aligned(IIO_DMA_MINALIGN);
> >       u8 rxbuf[4];
> >  };
> > @@ -484,21 +491,21 @@ static irqreturn_t sca3300_trigger_handler(int irq,
> void *p)
> >       struct iio_dev *indio_dev = pf->indio_dev;
> >       struct sca3300_data *data = iio_priv(indio_dev);
> >       int bit, ret, val, i = 0;
> > +     s16 *channels = (s16 *)data->buffer;
> >
> >       for_each_set_bit(bit, indio_dev->active_scan_mask,
> >                        indio_dev->masklength) {
> > -             ret = sca3300_read_reg(data,
> sca3300_channels[bit].address,
> > -                                    &val);
> > +             ret = sca3300_read_reg(data,
> > + indio_dev->channels[bit].address, &val);
> >               if (ret) {
> >                       dev_err_ratelimited(&data->spi->dev,
> >                               "failed to read register, error: %d\n",
> ret);
> >                       /* handled, but bailing out due to errors */
> >                       goto out;
> >               }
> > -             data->scan.channels[i++] = val;
> > +             channels[i++] = val;
> >       }
> >
> > -     iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
> > +     iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
> >
> iio_get_time_ns(indio_dev));
> >  out:
> >       iio_trigger_notify_done(indio_dev->trig);