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From:   Jean-Baptiste Maneyrol <JManeyrol@invensense.com>
To:     Andy Shevchenko <andy.shevchenko@gmail.com>,
        "trix@redhat.com" <trix@redhat.com>
CC:     Jonathan Cameron <jic23@kernel.org>,
        Hartmut Knaack <knaack.h@gmx.de>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Peter Meerwald <pmeerw@pmeerw.net>,
        =?iso-8859-2?Q?Micha=B3_Miros=B3aw?= <mirq-linux@rere.qmqm.pl>,
        Lee Jones <lee.jones@linaro.org>,
        linux-iio <linux-iio@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] iio: imu: inv_mpu6050: check for temp_fifo_enable
Thread-Topic: [PATCH] iio: imu: inv_mpu6050: check for temp_fifo_enable
Thread-Index: AQHWbmYc4AO8xECcpUKzCKFLtz5s/qkw/HaAgAS0usg=
Date:   Thu, 13 Aug 2020 08:04:06 +0000
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Hello,=0A=
=0A=
this is a case that should never be happening since available scan mask onl=
y advertise Accel + Temp, Gyro + Temp, or Accel + Gyro + Temp.=0A=
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 tempera=
ture compensation).=0A=
=0A=
So I think we can let this check as it is currently, since this is not a su=
pported configuration.=0A=
=0A=
Best regards,=0A=
JB=0A=
=0A=
=0A=
From: Andy Shevchenko <andy.shevchenko@gmail.com>=0A=
Sent: Monday, August 10, 2020 10:02=0A=
To: trix@redhat.com <trix@redhat.com>=0A=
Cc: Jonathan Cameron <jic23@kernel.org>; Hartmut Knaack <knaack.h@gmx.de>; =
Lars-Peter Clausen <lars@metafoo.de>; Peter Meerwald <pmeerw@pmeerw.net>; J=
ean-Baptiste Maneyrol <JManeyrol@invensense.com>; Micha=B3 Miros=B3aw <mirq=
-linux@rere.qmqm.pl>; Lee Jones <lee.jones@linaro.org>; linux-iio <linux-ii=
o@vger.kernel.org>; Linux Kernel Mailing List <linux-kernel@vger.kernel.org=
>=0A=
Subject: Re: [PATCH] iio: imu: inv_mpu6050: check for temp_fifo_enable =0A=
=A0=0A=
=A0CAUTION: 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 ope=
n attachments unless you recognize the sender and know the content is safe.=
=0A=
=0A=
On Sun, Aug 9, 2020 at 7:00 PM <trix@redhat.com> wrote:=0A=
>=0A=
> From: Tom Rix <trix@redhat.com>=0A=
>=0A=
> clang static analysis reports this problem=0A=
>=0A=
> inv_mpu_ring.c:181:18: warning: Division by zero=0A=
>=A0=A0=A0=A0=A0=A0=A0=A0 nb =3D fifo_count / bytes_per_datum;=0A=
>=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 ~~~~~~~~~~~^~~~~~~~~~~~~~~~~=0A=
>=0A=
> This is a false positive.=0A=
> Dividing by 0 is protected by this check=0A=
>=0A=
>=A0=A0=A0=A0=A0=A0=A0=A0 if (!(st->chip_config.accl_fifo_enable |=0A=
>=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 st->chip_config.gyro_fifo=
_enable |=0A=
>=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 st->chip_config.magn_fifo=
_enable))=0A=
>=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 goto end_session;=0A=
>=A0=A0=A0=A0=A0=A0=A0=A0 bytes_per_datum =3D 0;=0A=
>=0A=
> But there is another fifo, temp_fifo=0A=
>=0A=
>=A0=A0=A0=A0=A0=A0=A0=A0 if (st->chip_config.temp_fifo_enable)=0A=
>=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 bytes_per_datum +=3D INV_=
MPU6050_BYTES_PER_TEMP_SENSOR;=0A=
>=0A=
> Which would be skipped if it was the only enabled fifo.=0A=
> So add to the check.=0A=
>=0A=
=0A=
> Fixes: 2e4c0a5e2576 ("iio: imu: inv_mpu6050: add fifo temperature data su=
pport")=0A=
>=0A=
> Signed-off-by: Tom Rix <trix@redhat.com>=0A=
=0A=
There shouldn't be a blank line in between.=0A=
=0A=
Other than that,=0A=
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>=0A=
=0A=
=0A=
=0A=
> ---=0A=
>=A0 drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c | 1 +=0A=
>=A0 1 file changed, 1 insertion(+)=0A=
>=0A=
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c b/drivers/iio/imu=
/inv_mpu6050/inv_mpu_ring.c=0A=
> index b533fa2dad0a..5240a400dcb4 100644=0A=
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c=0A=
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c=0A=
> @@ -141,6 +141,7 @@ irqreturn_t inv_mpu6050_read_fifo(int irq, void *p)=
=0A=
>=0A=
>=A0=A0=A0=A0=A0=A0=A0=A0 if (!(st->chip_config.accl_fifo_enable |=0A=
>=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 st->chip_config.gyro_fifo=
_enable |=0A=
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 st->chip_config.temp_fifo_ena=
ble |=0A=
>=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 st->chip_config.magn_fifo=
_enable))=0A=
>=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 goto end_session;=0A=
>=A0=A0=A0=A0=A0=A0=A0=A0 bytes_per_datum =3D 0;=0A=
> --=0A=
> 2.18.1=0A=
>=0A=
=0A=
=0A=
--=0A=
With Best Regards,=0A=
Andy Shevchenko=