Hello,

this is a case that should never be happening since available scan mask only 
advertise Accel + Temp, Gyro + Temp, or Accel + Gyro + Temp.
More than that, temperature sensor is not working when MEMS engine is off. 
(it's only purpose it to measure temperature of the MEMS to do data temperature 
compensation).

So I think we can let this check as it is currently, since this is not a 
supported configuration.

Best regards,
JB


From: Andy Shevchenko <andy.shevche...@gmail.com>
Sent: Monday, August 10, 2020 10:02
To: t...@redhat.com <t...@redhat.com>
Cc: Jonathan Cameron <ji...@kernel.org>; Hartmut Knaack <knaac...@gmx.de>; 
Lars-Peter Clausen <l...@metafoo.de>; Peter Meerwald <pme...@pmeerw.net>; 
Jean-Baptiste Maneyrol <jmaney...@invensense.com>; Michał Mirosław 
<mirq-li...@rere.qmqm.pl>; Lee Jones <lee.jo...@linaro.org>; linux-iio 
<linux-...@vger.kernel.org>; Linux Kernel Mailing List 
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] iio: imu: inv_mpu6050: check for temp_fifo_enable 
 
 CAUTION: This email originated from outside of the organization. Please make 
sure the sender is who they say they are and do not click links or open 
attachments unless you recognize the sender and know the content is safe.

On Sun, Aug 9, 2020 at 7:00 PM <t...@redhat.com> wrote:
>
> From: Tom Rix <t...@redhat.com>
>
> clang static analysis reports this problem
>
> inv_mpu_ring.c:181:18: warning: Division by zero
>         nb = fifo_count / bytes_per_datum;
>              ~~~~~~~~~~~^~~~~~~~~~~~~~~~~
>
> This is a false positive.
> Dividing by 0 is protected by this check
>
>         if (!(st->chip_config.accl_fifo_enable |
>                 st->chip_config.gyro_fifo_enable |
>                 st->chip_config.magn_fifo_enable))
>                 goto end_session;
>         bytes_per_datum = 0;
>
> But there is another fifo, temp_fifo
>
>         if (st->chip_config.temp_fifo_enable)
>                 bytes_per_datum += INV_MPU6050_BYTES_PER_TEMP_SENSOR;
>
> Which would be skipped if it was the only enabled fifo.
> So add to the check.
>

> Fixes: 2e4c0a5e2576 ("iio: imu: inv_mpu6050: add fifo temperature data 
> support")
>
> Signed-off-by: Tom Rix <t...@redhat.com>

There shouldn't be a blank line in between.

Other than that,
Reviewed-by: Andy Shevchenko <andy.shevche...@gmail.com>



> ---
>  drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c 
> b/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c
> index b533fa2dad0a..5240a400dcb4 100644
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c
> @@ -141,6 +141,7 @@ irqreturn_t inv_mpu6050_read_fifo(int irq, void *p)
>
>         if (!(st->chip_config.accl_fifo_enable |
>                 st->chip_config.gyro_fifo_enable |
> +               st->chip_config.temp_fifo_enable |
>                 st->chip_config.magn_fifo_enable))
>                 goto end_session;
>         bytes_per_datum = 0;
> --
> 2.18.1
>


--
With Best Regards,
Andy Shevchenko

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