linux-kernel - Re: [PATCH] media: dw9714: Fix powerup sequence

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Message-ID: <CANiDSCsiu5E0nmm9dAgMGZ4y26cjwr8XKB1KRu2wZSVgdP-Brw@mail.gmail.com>
Date: Mon, 15 Dec 2025 09:46:46 +0100
From: Ricardo Ribalda <ribalda@...omium.org>
To: johannes.goede@....qualcomm.com
Cc: Sakari Ailus <sakari.ailus@...ux.intel.com>, 
	Mauro Carvalho Chehab <mchehab@...nel.org>, Ondrej Jirman <megi@....cz>, Hans Verkuil <hverkuil@...nel.org>, 
	linux-media@...r.kernel.org, linux-kernel@...r.kernel.org, 
	neil.sun@...uturecenter.com, naomi.huang@...uturecenter.com
Subject: Re: [PATCH] media: dw9714: Fix powerup sequence

Hi Hans

On Wed, 10 Dec 2025 at 09:21, <johannes.goede@....qualcomm.com> wrote:
>
> Hi,
>
> On 10-Dec-25 8:53 AM, Ricardo Ribalda wrote:
> > We have experienced seen multiple I2C errors while doing stress test on
> > the module:
> >
> > dw9714 i2c-PRP0001:01: dw9714_vcm_resume I2C failure: -5
> > dw9714 i2c-PRP0001:01: I2C write fail
> >
> > Inspecting the powerup sequence we found that it does not match the
> > documentation at:
> > https://blog.arducam.com/downloads/DW9714A-DONGWOON(Autofocus_motor_manual).pdf
> >
> > """
> > (2) DW9714A requires waiting time of 12ms after power on. During this
> > waiting time, the offset calibration of internal amplifier is
> > operating for minimization of output offset current .
> > """
> >
> > This patch increases the powerup delay to follow the documentation.
> >
> > Fixes: 9d00ccabfbb5 ("media: i2c: dw9714: Fix occasional probe errors")
> > Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>
>
> Thanks, patch looks good to me:
>
> Reviewed-by: Hans de Goede <johannes.goede@....qualcomm.com>

Some tags for the record

Tested-by: Neil Sun <neil.sun@...uturecenter.com>
Co-developed-by: Naomi Huang <naomi.huang@...uturecenter.com>


>
> Regards,
>
> Hans
>
>
>
>
> > ---
> >  drivers/media/i2c/dw9714.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/i2c/dw9714.c b/drivers/media/i2c/dw9714.c
> > index 1e7ad355a388cfc37253bd764ec8df98f59beeea..3288de539452ebae41daa0988b2d52f27a790da7 100644
> > --- a/drivers/media/i2c/dw9714.c
> > +++ b/drivers/media/i2c/dw9714.c
> > @@ -149,7 +149,7 @@ static int dw9714_power_up(struct dw9714_device *dw9714_dev)
> >
> >       gpiod_set_value_cansleep(dw9714_dev->powerdown_gpio, 0);
> >
> > -     usleep_range(1000, 2000);
> > +     usleep_range(12000, 14000);
> >
> >       return 0;
> >  }
> >
> > ---
> > base-commit: f7231cff1f3ff8259bef02dc4999bc132abf29cf
> > change-id: 20251210-dw9174-timing-9e58903399c9
> >
> > Best regards,
>


-- 
Ricardo Ribalda