On Sat, 5 Dec 2020 11:10:41 +0100
Lorenzo Bianconi <lorenzo@xxxxxxxxxx> wrote:
> Return a boolean value in st_sensors_new_samples_available routine in
> order to avoid an infinite loop in st_sensors_irq_thread if
> stat_drdy.addr is not defined or stat_drdy read fails
>
> Fixes: 90efe05562921 ("iio: st_sensors: harden interrupt handling")
> Reported-by: Jonathan Cameron <jic23@xxxxxxxxxx>
> Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
Oops. I should not noticed this and replied here.
See reply to previous version. I think this will create an infinite
loop in the obscure case of no status register + an edge interrupt.
My gut feeling is we can't support that combination so should fail
at probe time if it is specified. It's broken hardware / dt.
Jonathan
> ---
> Changes since v1:
> - return true if the sensor does not have stat_drdy register
> ---
> .../common/st_sensors/st_sensors_trigger.c | 20 ++++++++-----------
> 1 file changed, 8 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/iio/common/st_sensors/st_sensors_trigger.c b/drivers/iio/common/st_sensors/st_sensors_trigger.c
> index 0507283bd4c1..d3f047e9d778 100644
> --- a/drivers/iio/common/st_sensors/st_sensors_trigger.c
> +++ b/drivers/iio/common/st_sensors/st_sensors_trigger.c
> @@ -23,35 +23,31 @@
> * @sdata: Sensor data.
> *
> * returns:
> - * 0 - no new samples available
> - * 1 - new samples available
> - * negative - error or unknown
> + * false - no new samples available or read error
> + * true - new samples available
> */
> -static int st_sensors_new_samples_available(struct iio_dev *indio_dev,
> - struct st_sensor_data *sdata)
> +static bool st_sensors_new_samples_available(struct iio_dev *indio_dev,
> + struct st_sensor_data *sdata)
> {
> int ret, status;
>
> /* How would I know if I can't check it? */
> if (!sdata->sensor_settings->drdy_irq.stat_drdy.addr)
> - return -EINVAL;
> + return true;
>
> /* No scan mask, no interrupt */
> if (!indio_dev->active_scan_mask)
> - return 0;
> + return false;
>
> ret = regmap_read(sdata->regmap,
> sdata->sensor_settings->drdy_irq.stat_drdy.addr,
> &status);
> if (ret < 0) {
> dev_err(sdata->dev, "error checking samples available\n");
> - return ret;
> + return false;
> }
>
> - if (status & sdata->sensor_settings->drdy_irq.stat_drdy.mask)
> - return 1;
> -
> - return 0;
> + return !!(status & sdata->sensor_settings->drdy_irq.stat_drdy.mask);
> }
>
> /**
