Re: [PATCH 1/2] iio: imu: inv-mpu9150: fix irq ack preventing irq storms

[Jonathan Cameron <jic23@kernel.org>]

On Fri, 30 Jan 2026 16:17:58 +0000
Jean-Baptiste Maneyrol <Jean-Baptiste.Maneyrol@tdk.com> wrote:

> >
> >________________________________________
> >From: Jonathan Cameron <jic23@kernel.org>
> >Sent: Sunday, January 11, 2026 13:30
> >To: akemnade@kernel.org <akemnade@kernel.org>
> >Cc: Jean-Baptiste Maneyrol <Jean-Baptiste.Maneyrol@tdk.com>; David Lechner <dlechner@baylibre.com>; Nuno Sá <nuno.sa@analog.com>; Andy Shevchenko <andy@kernel.org>; Aaro Koskinen <aaro.koskinen@iki.fi>; Andreas Kemnade <andreas@kemnade.info>; Kevin Hilman <khilman@baylibre.com>; Roger Quadros <rogerq@kernel.org>; Tony Lindgren <tony@atomide.com>; Rob Herring <robh@kernel.org>; Krzysztof Kozlowski <krzk+dt@kernel.org>; Conor Dooley <conor+dt@kernel.org>; Jonathan Cameron <Jonathan.Cameron@huawei.com>; linux-iio@vger.kernel.org <linux-iio@vger.kernel.org>; linux-kernel@vger.kernel.org <linux-kernel@vger.kernel.org>; linux-omap@vger.kernel.org <linux-omap@vger.kernel.org>; devicetree@vger.kernel.org <devicetree@vger.kernel.org>
> >Subject: Re: [PATCH 1/2] iio: imu: inv-mpu9150: fix irq ack preventing irq storms
> > 
> >On Wed, 31 Dec 2025 22: 14: 16 +0100 akemnade@ kernel. org wrote: > From: Andreas Kemnade <andreas@ kemnade. info> > > IRQ needs to be acked. for some odd reasons, reading from irq status does > not reliable help, enable acking from
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> >On Wed, 31 Dec 2025 22:14:16 +0100
> >akemnade@kernel.org wrote:
> >  
> >> From: Andreas Kemnade <andreas@kemnade.info>
> >> 
> >> IRQ needs to be acked. for some odd reasons, reading from irq status does
> >> not reliable help, enable acking from any register to be on the safe side
> >> and read the irq status register. Comments in the code indicate a known
> >> unreliability with that register.
> >> The blamed commit was tested with mpu6050 in lg,p895 and lg,p880 according
> >> to Tested-bys. But with the MPU9150 in the Epson Moverio BT-200 this leads
> >> to irq storms without properly acking the irq.
> >> 
> >> Fixes: 0a3b517c8089 ("iio: imu: inv_mpu6050: fix interrupt status read for old buggy chips")
> >> Signed-off-by: Andreas Kemnade <andreas@kemnade.info>  
> >Jean-Baptiste,
> >
> >If you have time to look at this that would be great.
> >
> >Whilst here I'll note the defines in this driver could really do with consistency
> >improvements.  I'd like to see GENMASK() and BIT() used everywhere.
> >Currently it's mostly the style used in this patch with a few fields in
> >the newer style.  
> >
> >Thanks
> >
> >Jonathan  
> 
> Hello Jonathan,
> 
> sorry for the late response. This is a very old chip, I'm sorry I won't be
> able to check the modification on my side.
> 
> By looking at it, it seems correct if it is indeed fixing the issue. I'm
> giving my acknowledgement to the patch.
> 
> Acked-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
Good enough for me.
Applied to my local tree for now as we are close to the merge window
and I'll probably rebase before pushing these out.

Thanks,

Jonathan

> 
> Thanks,
> JB
> 
> >  
> >> ---
> >>  drivers/iio/imu/inv_mpu6050/inv_mpu_core.c    | 8 ++++++++
> >>  drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h     | 2 ++
> >>  drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c | 5 ++++-
> >>  3 files changed, 14 insertions(+), 1 deletion(-)
> >> 
> >> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
> >> index b2fa1f4957a5b..5796896d54cd8 100644
> >> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
> >> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
> >> @@ -1943,6 +1943,14 @@ int inv_mpu_core_probe(struct regmap *regmap, int irq, const char *name,
> >>  			irq_type);
> >>  		return -EINVAL;
> >>  	}
> >> +
> >> +	/*
> >> +	 * Acking interrupts by status register does not work reliably
> >> +	 * but seem to work when this bit is set.
> >> +	 */
> >> +	if (st->chip_type == INV_MPU9150)
> >> +		st->irq_mask |= INV_MPU6050_INT_RD_CLEAR;
> >> +
> >>  	device_set_wakeup_capable(dev, true);
> >>  
> >>  	st->vdd_supply = devm_regulator_get(dev, "vdd");
> >> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
> >> index 211901f8b8eb6..6239b1a803f77 100644
> >> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
> >> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
> >> @@ -390,6 +390,8 @@ struct inv_mpu6050_state {
> >>  /* enable level triggering */
> >>  #define INV_MPU6050_LATCH_INT_EN	0x20
> >>  #define INV_MPU6050_BIT_BYPASS_EN	0x2
> >> +/* allow acking interrupts by any register read */
> >> +#define INV_MPU6050_INT_RD_CLEAR	0x10
> >>  
> >>  /* Allowed timestamp period jitter in percent */
> >>  #define INV_MPU6050_TS_PERIOD_JITTER	4
> >> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c
> >> index 10a4733420759..22c1ce66f99ee 100644
> >> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c
> >> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c
> >> @@ -248,7 +248,6 @@ static irqreturn_t inv_mpu6050_interrupt_handle(int irq, void *p)
> >>  	switch (st->chip_type) {
> >>  	case INV_MPU6000:
> >>  	case INV_MPU6050:
> >> -	case INV_MPU9150:
> >>  		/*
> >>  		 * WoM is not supported and interrupt status read seems to be broken for
> >>  		 * some chips. Since data ready is the only interrupt, bypass interrupt
> >> @@ -257,6 +256,10 @@ static irqreturn_t inv_mpu6050_interrupt_handle(int irq, void *p)
> >>  		wom_bits = 0;
> >>  		int_status = INV_MPU6050_BIT_RAW_DATA_RDY_INT;
> >>  		goto data_ready_interrupt;
> >> +	case INV_MPU9150:
> >> +		/* IRQ needs to be acked */
> >> +		wom_bits = 0;
> >> +		break;
> >>  	case INV_MPU6500:
> >>  	case INV_MPU6515:
> >>  	case INV_MPU6880:
> >>   
> >
>