All of lore.kernel.org
 help / color / mirror / Atom feed
From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Jacopo Mondi <jacopo+renesas@jmondi.org>
Cc: Kieran Bingham <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 16/16] media: i2c: gmsl: Use 339Kbps I2C bit-rate
Date: Mon, 22 Feb 2021 04:06:48 +0200	[thread overview]
Message-ID: <YDMRuGL1HeKeYL18@pendragon.ideasonboard.com> (raw)
In-Reply-To: <aa7d8a9c-93a0-8c14-4fe4-b831e7b45d88@ideasonboard.com>

Hi Jacopo,

Thank you for the patch.

On Thu, Feb 18, 2021 at 04:07:30PM +0000, Kieran Bingham wrote:
> On 16/02/2021 17:41, Jacopo Mondi wrote:
> > With the camera modules initialization routines now running with
> > the noise immunity threshold enabled, it is possible to restore
> > the bit rate of the I2C transactions transported on the GMSL control
> > channel to 339 Kbps.
> > 
> > The 339 Kbps bit rate represents the default setting for the serializer
> > and the deserializer chips, and the setup/hold time and slave timeout
> > time in use are calibrate to support that rate.
> 
> s/calibrate/calibrated/
> 
> Does that mean the setup/hold time and timeouts should be adjusted based
> on the i2c speed? (which we have not been doing?)
> 
> With all of your other reliability improvements, does *this* change
> alone have any difference or impact on reliability?
> 
> I.e. if we go slower (stay at current speed) - would we be more reliable?
> 
> Is there a reliability improvement by making this speed faster?
> 
> I presume we don't have a way to convey the i2c bus speed between the
> max9286 and the max9271 currently? Seems a bit like a bus parameter....

There's a max bus speed DT parameter that we can use. And I think we
should, as, in theory at least, there's no guarantee that all the
devices behind the serializer can operate at 400kbps.

> > Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> > ---
> >  drivers/media/i2c/max9286.c | 2 +-
> >  drivers/media/i2c/rdacm20.c | 2 +-
> >  drivers/media/i2c/rdacm21.c | 2 +-
> >  3 files changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c
> > index aa01d5bb79ef..0b620f2f8c41 100644
> > --- a/drivers/media/i2c/max9286.c
> > +++ b/drivers/media/i2c/max9286.c
> > @@ -330,7 +330,7 @@ static int max9286_i2c_mux_init(struct max9286_priv *priv)
> >  static void max9286_configure_i2c(struct max9286_priv *priv, bool localack)
> >  {
> >  	u8 config = MAX9286_I2CSLVSH_469NS_234NS | MAX9286_I2CSLVTO_1024US |
> > -		    MAX9286_I2CMSTBT_105KBPS;
> > +		    MAX9286_I2CMSTBT_339KBPS;
> >  
> >  	if (localack)
> >  		config |= MAX9286_I2CLOCACK;
> > diff --git a/drivers/media/i2c/rdacm20.c b/drivers/media/i2c/rdacm20.c
> > index 0632ef98eea7..d45e8b0e52a0 100644
> > --- a/drivers/media/i2c/rdacm20.c
> > +++ b/drivers/media/i2c/rdacm20.c
> > @@ -450,7 +450,7 @@ static int rdacm20_init(struct v4l2_subdev *sd, unsigned int val)
> >  	ret = max9271_configure_i2c(&dev->serializer,
> >  				    MAX9271_I2CSLVSH_469NS_234NS |
> >  				    MAX9271_I2CSLVTO_1024US |
> > -				    MAX9271_I2CMSTBT_105KBPS);
> > +				    MAX9271_I2CMSTBT_339KBPS);
> >  	if (ret)
> >  		return ret;
> >  
> > diff --git a/drivers/media/i2c/rdacm21.c b/drivers/media/i2c/rdacm21.c
> > index 80b6f16f87a8..552985026458 100644
> > --- a/drivers/media/i2c/rdacm21.c
> > +++ b/drivers/media/i2c/rdacm21.c
> > @@ -442,7 +442,7 @@ static int rdacm21_init(struct v4l2_subdev *sd, unsigned int val)
> >  	ret = max9271_configure_i2c(&dev->serializer,
> >  				    MAX9271_I2CSLVSH_469NS_234NS |
> >  				    MAX9271_I2CSLVTO_1024US |
> > -				    MAX9271_I2CMSTBT_105KBPS);
> > +				    MAX9271_I2CMSTBT_339KBPS);
> >  	if (ret)
> >  		return ret;
> >  

-- 
Regards,

Laurent Pinchart

      reply	other threads:[~2021-02-22  2:08 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
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 [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=YDMRuGL1HeKeYL18@pendragon.ideasonboard.com \
    --to=laurent.pinchart@ideasonboard.com \
    --cc=geert@linux-m68k.org \
    --cc=jacopo+renesas@jmondi.org \
    --cc=kieran.bingham+renesas@ideasonboard.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-media@vger.kernel.org \
    --cc=linux-renesas-soc@vger.kernel.org \
    --cc=mchehab@kernel.org \
    --cc=niklas.soderlund+renesas@ragnatech.se \
    --subject='Re: [PATCH 16/16] media: i2c: gmsl: Use 339Kbps I2C bit-rate' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.