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

From: Jonathan Cameron
Date: Fri Jul 01 2022 - 12:36:35 EST


On Fri, 1 Jul 2022 02:30:30 +0000
LI Qingwu <Qing-wu.Li@xxxxxxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxxxxxxx>

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

> ---
> 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);