Re: LSM9DS1 testing with st_lsm6dsx driver

[Bobby Jones <rjones@gateworks.com>]

> > > LSM9DS1 does not support hw FIFO for the moment. Are you trying to enable
> > > buffered reading?
> >
> > I am not manually interacting with the device at all when this
> > exception occurs. This happens during the driver probe.
> >
> > > Could you please try if the following patch helps? (just compiled)
> >
> > I no longer receive the exception with this patch and it makes sense, thanks.
>
> Hi Bobby,
>
> thx a lot for testing. Could you please try to drop the previous patch and
> apply the following one? Does it fix the issue as well?

No problem, happy to help. I just tested, and unfortunately the issue
is still present with this patch.
I gave the datasheet and the hardware reference manual of the
connected CPU a closer look and suspected a problem with my pin
config. However even after various combinations of pull ups/downs and
IRQ_TYPE_LEVEL_LOW/IRQ_TYPE_LEVEL_HIGH the same exception occurs, so I
don't think that there's an issue with pin config stopping the
interrupt line from being deasserted.

>
> iio: imu: st_lsm6dsx: check read_fifo pointer in st_lsm6dsx_handler_thread
>
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> ---
>  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c
> index b0f3da1976e4..f4fd4842bd79 100644
> --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c
> +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c
> @@ -666,6 +666,9 @@ static irqreturn_t st_lsm6dsx_handler_thread(int irq, void *private)
>         struct st_lsm6dsx_hw *hw = private;
>         int count;
>
> +       if (!hw->settings->fifo_ops.read_fifo)
> +               return IRQ_NONE;
> +
>         mutex_lock(&hw->fifo_lock);
>         count = hw->settings->fifo_ops.read_fifo(hw);
>         mutex_unlock(&hw->fifo_lock);
> --
> 2.21.0
>
> >
> > For context I'm working with a board that has every data ready and
> > interrupt signal connected to the LSM9DS1. Could you clarify what the
> > proper usage of the "st,drdy-int-pin" would be in this case and
> > whether or not I need more than one interrupt called out in my device
> > tree node?
> > I'm not really understanding how they're currently being utilized for
> > this device in the driver.
>
> For the moment irq line in lsm9ds1 (acc/gyro) is not used at all,
> so you can omit the "st,drdy-int-pin" property
>
> >
> > Also, I know support for this device was added recently and the combo
> > device hardware FIFO is complex, but is support for this something
> > that's currently being worked on?
>
> It is actually in my ToDo list but I have no this device at the moment, so
> patches are welcome :)
>
> Regards,
> Lorenzo
>
> >
> > Thanks,
> > Bobby Jones
> >
> > > Regards,
> > > Lorenzo
> > >
> > > iio: imu: st_lsm6dsx: do not configure the fifo if not supported
> > >
> > > Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> > > ---
> > >  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> > > index b65a6ca775e0..90a0e5ce44e5 100644
> > > --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> > > +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> > > @@ -1572,7 +1572,7 @@ int st_lsm6dsx_probe(struct device *dev, int irq, int hw_id,
> > >                         return err;
> > >         }
> > >
> > > -       if (hw->irq > 0) {
> > > +       if (hw->irq > 0 && hw->settings->fifo_ops.update_fifo) {
> > >                 err = st_lsm6dsx_fifo_setup(hw);
> > >                 if (err < 0)
> > >                         return err;
> > > --
> > > 2.21.0
> > >
> > >