On Thu, Apr 22, 2021 at 1:17 PM Nuno Sa <nuno.sa@xxxxxxxxxx> wrote:
>
> Typically, in burst mode, the device cannot operate at it's full spi
> speed. Hence, the spi transfers for burst mode have to take this into
> account. With this change we avoid a potential race with the spi core as
> drivers were 'hacking' the device 'max_speed_hz' directly in the
> trigger handler.
>
Reviewed-by: Alexandru Ardelean <ardeleanalex@xxxxxxxxx>
> Signed-off-by: Nuno Sa <nuno.sa@xxxxxxxxxx>
> ---
> drivers/iio/imu/adis_buffer.c | 4 ++++
> include/linux/iio/imu/adis.h | 2 ++
> 2 files changed, 6 insertions(+)
>
> diff --git a/drivers/iio/imu/adis_buffer.c b/drivers/iio/imu/adis_buffer.c
> index dda367071980..82239da2f441 100644
> --- a/drivers/iio/imu/adis_buffer.c
> +++ b/drivers/iio/imu/adis_buffer.c
> @@ -51,9 +51,13 @@ static int adis_update_scan_mode_burst(struct iio_dev *indio_dev,
> adis->xfer[0].tx_buf = tx;
> adis->xfer[0].bits_per_word = 8;
> adis->xfer[0].len = 2;
> + if (adis->data->burst_max_speed_hz)
> + adis->xfer[0].speed_hz = adis->data->burst_max_speed_hz;
> adis->xfer[1].rx_buf = adis->buffer;
> adis->xfer[1].bits_per_word = 8;
> adis->xfer[1].len = burst_length;
> + if (adis->data->burst_max_speed_hz)
> + adis->xfer[1].speed_hz = adis->data->burst_max_speed_hz;
>
> spi_message_init(&adis->msg);
> spi_message_add_tail(&adis->xfer[0], &adis->msg);
> diff --git a/include/linux/iio/imu/adis.h b/include/linux/iio/imu/adis.h
> index f9b728d490b1..cf49997d5903 100644
> --- a/include/linux/iio/imu/adis.h
> +++ b/include/linux/iio/imu/adis.h
> @@ -55,6 +55,7 @@ struct adis_timeout {
> * this should be the minimum size supported by the device.
> * @burst_max_len: Holds the maximum burst size when the device supports
> * more than one burst mode with different sizes
> + * @burst_max_speed_hz: Maximum spi speed that can be used in burst mode
> */
> struct adis_data {
> unsigned int read_delay;
> @@ -83,6 +84,7 @@ struct adis_data {
> unsigned int burst_reg_cmd;
> unsigned int burst_len;
> unsigned int burst_max_len;
> + unsigned int burst_max_speed_hz;
> };
>
> /**
> --
> 2.31.1
>
