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From: Jacopo Mondi <jacopo@jmondi.org>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Jacopo Mondi <jacopo+renesas@jmondi.org>,
	kieran.bingham+renesas@ideasonboard.com,
	niklas.soderlund+renesas@ragnatech.se, geert@linux-m68k.org,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 09/16] media: i2c: rdacm21: Re-work OV10640 initialization
Date: Mon, 22 Feb 2021 16:19:13 +0100	[thread overview]
Message-ID: <20210222151913.a4teevpafzxi2xlz@uno.localdomain> (raw)
In-Reply-To: <YDMIfTtc7ottA6Ir@pendragon.ideasonboard.com>

Hi

On Mon, Feb 22, 2021 at 03:27:25AM +0200, Laurent Pinchart wrote:
> Hi Jacopo,
>
> Thank you for the patch.
>
> On Tue, Feb 16, 2021 at 06:41:39PM +0100, Jacopo Mondi wrote:
> > The OV10640 image sensor reset and powerdown on signals are controlled
>
> s/ on//
>
> > by the embedded OV490 ISP. The current reset procedure does not respect
> > the 1 millisecond power-up delay and releases the reset signal before
> > the powerdown one.
> >
> > Fix the OV10640 power up sequence by releasing the powerdown signal,
> > waiting the mandatory 1 millisecond power up delay and then releasing
> > the reset signal. The reset delay is not characterized in the chip
> > manual if not as "255 XVCLK + initialization". Wait for at least 3
> > milliseconds to guarantee the SCCB bus is available.
> >
> > This commit fixes a sporadic start-up error triggered by a failure to
> > read the OV10640 chip ID:
> > rdacm21 8-0054: OV10640 ID mismatch: (0x01)
> >
> > Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> > ---
> >  drivers/media/i2c/rdacm21.c | 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/media/i2c/rdacm21.c b/drivers/media/i2c/rdacm21.c
> > index b22a2ca5340b..c420a6b96879 100644
> > --- a/drivers/media/i2c/rdacm21.c
> > +++ b/drivers/media/i2c/rdacm21.c
> > @@ -333,13 +333,15 @@ static int ov10640_initialize(struct rdacm21_device *dev)
> >  {
> >  	u8 val;
> >
> > -	/* Power-up OV10640 by setting RESETB and PWDNB pins high. */
> > +	/* Power-up OV10640 by setting PWDNB and RESETB pins high. */
> >  	ov490_write_reg(dev, OV490_GPIO_SEL0, OV490_GPIO0);
> >  	ov490_write_reg(dev, OV490_GPIO_SEL1, OV490_SPWDN0);
> >  	ov490_write_reg(dev, OV490_GPIO_DIRECTION0, OV490_GPIO0);
> >  	ov490_write_reg(dev, OV490_GPIO_DIRECTION1, OV490_SPWDN0);
> > -	ov490_write_reg(dev, OV490_GPIO_OUTPUT_VALUE0, OV490_GPIO0);
> > +
> >  	ov490_write_reg(dev, OV490_GPIO_OUTPUT_VALUE0, OV490_SPWDN0);
>
> Shouldn't this be OV490_GPIO_OUTPUT_VALUE1 ?
>

Ouch, yes it should

> > +	usleep_range(1500, 3000);
> > +	ov490_write_reg(dev, OV490_GPIO_OUTPUT_VALUE0, OV490_GPIO0);
>
> I'm a bit puzzled by why this patch would improve the ID read issue,
> given that it sets GPIO0 to 1, then sets GPIO0 to 1, compared to
> previously setting GPIO0 to 1 following by setting GPIO0 to 1 :-) Maybe

:) it doesn't make things worse at least!

> it's the additional delay ? In any case, it would probably be a good
> idea to perform additional tests after fixing this.

I think the additional delay plays indeed a role, as it's a
requirement in the datasheet that was not respected, but now I'm dead
scared to fix this and find out I've opened another can of worms..

>
> >  	usleep_range(3000, 5000);
> >
> >  	/* Read OV10640 ID to test communications. */
>
> --
> Regards,
>
> Laurent Pinchart

  reply	other threads:[~2021-02-22 15:28 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-16 17:41 [PATCH 00/16] media: i2c: GMSL reliability improvements Jacopo Mondi
2021-02-16 17:41 ` [PATCH 01/16] media: i2c: rdacm20: Enable noise immunity Jacopo Mondi
2021-02-17 12:55   ` Kieran Bingham
2021-02-22  0:49     ` Laurent Pinchart
2021-02-22 14:59       ` Jacopo Mondi
2021-02-24 20:35         ` Laurent Pinchart
2021-02-16 17:41 ` [PATCH 02/16] media: i2c: rdacm20: Embedded 'serializer' field Jacopo Mondi
2021-02-17 12:56   ` Kieran Bingham
2021-02-22  0:58   ` Laurent Pinchart
2021-02-16 17:41 ` [PATCH 03/16] media: i2c: rdacm20: Replace goto with a loop Jacopo Mondi
2021-02-17 13:01   ` Kieran Bingham
2021-02-22  1:05     ` Laurent Pinchart
2021-02-22 15:06       ` Jacopo Mondi
2021-02-24 20:27         ` Laurent Pinchart
2021-02-25  8:56           ` Kieran Bingham
2021-02-16 17:41 ` [PATCH 04/16] media: i2c: rdacm20: Report camera module name Jacopo Mondi
2021-02-17 13:02   ` Kieran Bingham
2021-02-22  1:06   ` Laurent Pinchart
2021-02-16 17:41 ` [PATCH 05/16] media: i2c: rdacm20: Check return values Jacopo Mondi
2021-02-17 13:08   ` Kieran Bingham
2021-02-22  1:09   ` Laurent Pinchart
2021-02-22 15:08     ` Jacopo Mondi
2021-02-16 17:41 ` [PATCH 06/16] media: i2c: rdacm20: Re-work ov10635 reset Jacopo Mondi
2021-02-17 13:22   ` Kieran Bingham
2021-02-22  1:15   ` Laurent Pinchart
2021-02-16 17:41 ` [PATCH 07/16] media: i2c: rdacm2x: Fix wake up delay Jacopo Mondi
2021-02-17  8:02   ` Geert Uytterhoeven
2021-02-17 13:33   ` Kieran Bingham
2021-02-22  1:18     ` Laurent Pinchart
2021-02-22 15:11       ` Jacopo Mondi
2021-02-24 20:29         ` Laurent Pinchart
2021-02-16 17:41 ` [PATCH 08/16] media: i2c: max9286: Adjust parameters indent Jacopo Mondi
2021-02-17 13:36   ` Kieran Bingham
2021-02-22  1:20   ` Laurent Pinchart
2021-02-16 17:41 ` [PATCH 09/16] media: i2c: rdacm21: Re-work OV10640 initialization Jacopo Mondi
2021-02-17  8:06   ` Geert Uytterhoeven
2021-02-17 13:55   ` Kieran Bingham
2021-02-22  1:27   ` Laurent Pinchart
2021-02-22 15:19     ` Jacopo Mondi [this message]
2021-02-24 20:30       ` Laurent Pinchart
2021-02-16 17:41 ` [PATCH 10/16] media: i2c: max9286: Rename reverse_channel_mv Jacopo Mondi
2021-02-17  8:07   ` Geert Uytterhoeven
2021-02-18 15:06   ` Kieran Bingham
2021-02-22  1:29   ` Laurent Pinchart
2021-02-16 17:41 ` [PATCH 11/16] media: i2c: max9286: Cache channel amplitude Jacopo Mondi
2021-02-17  8:08   ` Geert Uytterhoeven
2021-02-18 15:39   ` Kieran Bingham
2021-02-22  1:33   ` Laurent Pinchart
2021-02-16 17:41 ` [PATCH 12/16] media: i2c: max9286: Define high " Jacopo Mondi
2021-02-18 15:39   ` Kieran Bingham
2021-02-22  1:35   ` Laurent Pinchart
2021-02-16 17:41 ` [PATCH 13/16] media: i2c: rdacm2x: Implement .init() subdev op Jacopo Mondi
2021-02-17  8:17   ` Geert Uytterhoeven
2021-02-18 16:13   ` Kieran Bingham
2021-02-22  1:52     ` Laurent Pinchart
2021-02-16 17:41 ` [PATCH 14/16] media: i2c: max9286: Initialize remotes when bound Jacopo Mondi
2021-02-17  8:19   ` Geert Uytterhoeven
2021-02-18 16:00   ` Kieran Bingham
2021-02-22  2:03   ` Laurent Pinchart
2021-02-16 17:41 ` [PATCH 15/16] media: i2c: max9286: Rework comments in .bound() Jacopo Mondi
2021-02-18 16:03   ` Kieran Bingham
2021-02-16 17:41 ` [PATCH 16/16] media: i2c: gmsl: Use 339Kbps I2C bit-rate Jacopo Mondi
2021-02-17  8:19   ` Geert Uytterhoeven
2021-02-18 16:07   ` Kieran Bingham
2021-02-22  2:06     ` Laurent Pinchart

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