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Date: Mon, 18 Dec 2023 12:58:18 +0100
From: Tommaso Merciai <tomm.merciai@gmail.com>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: linuxfancy@googlegroups.com, sakari.ailus@linux.intel.com,
	Martin Hecht <martin.hecht@avnet.eu>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] media: i2c: alvium: store frame interval in subdev
 state
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On Mon, Dec 18, 2023 at 01:44:37PM +0200, Laurent Pinchart wrote:
> On Mon, Dec 18, 2023 at 12:39:53PM +0100, Tommaso Merciai wrote:
> > On Mon, Dec 18, 2023 at 01:36:18PM +0200, Laurent Pinchart wrote:
> > > On Mon, Dec 18, 2023 at 12:19:36PM +0100, Tommaso Merciai wrote:
> > > > On Mon, Dec 18, 2023 at 01:03:31PM +0200, Laurent Pinchart wrote:
> > > > > On Mon, Dec 18, 2023 at 11:30:38AM +0100, Tommaso Merciai wrote:
> > > > > > On Mon, Dec 18, 2023 at 04:59:05AM +0200, Laurent Pinchart wrote:
> > > > > > > On Fri, Dec 15, 2023 at 09:24:52AM +0100, Tommaso Merciai wrote:
> > > > > > > > Use the newly added storage for frame interval in the subdev state to
> > > > > > > > simplify the driver.
> > > > > > > > 
> > > > > > > > Signed-off-by: Tommaso Merciai <tomm.merciai@gmail.com>
> > > > > > > > ---
> > > > > > > >  drivers/media/i2c/alvium-csi2.c | 40 ++++++++++-----------------------
> > > > > > > >  drivers/media/i2c/alvium-csi2.h |  2 --
> > > > > > > >  2 files changed, 12 insertions(+), 30 deletions(-)
> > > > > > > > 
> > > > > > > > diff --git a/drivers/media/i2c/alvium-csi2.c b/drivers/media/i2c/alvium-csi2.c
> > > > > > > > index fde456357be1..81f683b3c849 100644
> > > > > > > > --- a/drivers/media/i2c/alvium-csi2.c
> > > > > > > > +++ b/drivers/media/i2c/alvium-csi2.c
> > > > > > > > @@ -1643,25 +1643,6 @@ static int alvium_hw_init(struct alvium_dev *alvium)
> > > > > > > >  }
> > > > > > > >  
> > > > > > > >  /* --------------- Subdev Operations --------------- */
> > > > > > > > -
> > > > > > > > -static int alvium_g_frame_interval(struct v4l2_subdev *sd,
> > > > > > > > -				   struct v4l2_subdev_state *sd_state,
> > > > > > > > -				   struct v4l2_subdev_frame_interval *fi)
> > > > > > > > -{
> > > > > > > > -	struct alvium_dev *alvium = sd_to_alvium(sd);
> > > > > > > > -
> > > > > > > > -	/*
> > > > > > > > -	 * FIXME: Implement support for V4L2_SUBDEV_FORMAT_TRY, using the V4L2
> > > > > > > > -	 * subdev active state API.
> > > > > > > > -	 */
> > > > > > > > -	if (fi->which != V4L2_SUBDEV_FORMAT_ACTIVE)
> > > > > > > > -		return -EINVAL;
> > > > > > > > -
> > > > > > > > -	fi->interval = alvium->frame_interval;
> > > > > > > > -
> > > > > > > > -	return 0;
> > > > > > > > -}
> > > > > > > > -
> > > > > > > >  static int alvium_s_frame_interval(struct v4l2_subdev *sd,
> > > > > > > >  				   struct v4l2_subdev_state *sd_state,
> > > > > > > >  				   struct v4l2_subdev_frame_interval *fi)
> > > > > > > > @@ -1669,6 +1650,7 @@ static int alvium_s_frame_interval(struct v4l2_subdev *sd,
> > > > > > > >  	struct alvium_dev *alvium = sd_to_alvium(sd);
> > > > > > > >  	struct device *dev = &alvium->i2c_client->dev;
> > > > > > > >  	u64 req_fr, dft_fr, min_fr, max_fr;
> > > > > > > > +	struct v4l2_fract *interval;
> > > > > > > >  	int ret;
> > > > > > > >  
> > > > > > > >  	/*
> > > > > > > 
> > > > > > > You should drop the FIXME comment here and the ACTIVE check...
> > > > > > 
> > > > > > Oks, thanks.
> > > > > > 
> > > > > > > > @@ -1701,9 +1683,10 @@ static int alvium_s_frame_interval(struct v4l2_subdev *sd,
> > > > > > > >  	if (req_fr >= max_fr && req_fr <= min_fr)
> > > > > > > >  		req_fr = dft_fr;
> > > > > > > >  
> > > > > > > > -	alvium->fr = req_fr;
> > > > > > > > -	alvium->frame_interval.numerator = fi->interval.numerator;
> > > > > > > > -	alvium->frame_interval.denominator = fi->interval.denominator;
> > > > > > > > +	interval = v4l2_subdev_state_get_interval(sd_state, 0);
> > > > > > > > +
> > > > > > > > +	interval->numerator = fi->interval.numerator;
> > > > > > > > +	interval->denominator = fi->interval.denominator;
> > > > > > > >  
> > > > > > > 
> > > > > > > ... and here only call alvium_set_frame_rate() for the ACTIVE frame
> > > > > > > interval.
> > > > > > 
> > > > > > I don't completely got this comment, can you give me more details about
> > > > > > please. Thanks in advance!
> > > > > 
> > > > > alvium_s_frame_interval() can be called both for the TRY and ACTIVE
> > > > > status. The hardware registers should be written only for the ACTIVE
> > > > > state.
> > > > 
> > > > Do you think could be sufficient an if check like this?
> > > > 
> > > > -	return alvium_set_frame_rate(alvium, req_fr);
> > > > +	if (fi->which == V4L2_SUBDEV_FORMAT_ACTIVE)
> > > > +		return alvium_set_frame_rate(alvium, req_fr);
> > > > +
> > > > +	return ret;
> > > 
> > > That's the idea, yes. The "return ret" can become "return 0". Or you
> > > could write
> > > 
> > > 	if (fi->which != V4L2_SUBDEV_FORMAT_ACTIVE)
> > > 		return 0;
> > > 
> > > 	return alvium_set_frame_rate(alvium, req_fr);
> > > 
> > > >  }
> > 
> > (This is my personal idea eh :) )
> > 
> > Maybe better:
> > 
> > 	if (fi->which == V4L2_SUBDEV_FORMAT_ACTIVE)
> > 		ret = alvium_set_frame_rate(alvium, req_fr);
> > 
> > 	return ret;
> 
> Works fine too (assuming ret gets initialized properly).

Arg... good catch, thanks. :)
I will take your proposal then into v2.

Thanks again! :),
Tommaso

> 
> > > > > > > > @@ -1853,6 +1836,7 @@ static int alvium_init_state(struct v4l2_subdev *sd,
> > > > > > > >  {
> > > > > > > >  	struct alvium_dev *alvium = sd_to_alvium(sd);
> > > > > > > >  	struct alvium_mode *mode = &alvium->mode;
> > > > > > > > +	struct v4l2_fract *interval;
> > > > > > > >  	struct v4l2_subdev_format sd_fmt = {
> > > > > > > >  		.which = V4L2_SUBDEV_FORMAT_TRY,
> > > > > > > >  		.format = alvium_csi2_default_fmt,
> > > > > > > > @@ -1870,6 +1854,11 @@ static int alvium_init_state(struct v4l2_subdev *sd,
> > > > > > > >  	*v4l2_subdev_state_get_crop(state, 0) = sd_crop.rect;
> > > > > > > >  	*v4l2_subdev_state_get_format(state, 0) = sd_fmt.format;
> > > > > > > >  
> > > > > > > > +	/* Setup initial frame interval*/
> > > > > > > > +	interval = v4l2_subdev_state_get_interval(state, 0);
> > > > > > > > +	interval->numerator = 1;
> > > > > > > > +	interval->denominator = ALVIUM_DEFAULT_FR_HZ;
> > > > > > > > +
> > > > > > > >  	return 0;
> > > > > > > >  }
> > > > > > > >  
> > > > > > > > @@ -2239,7 +2228,7 @@ static const struct v4l2_subdev_pad_ops alvium_pad_ops = {
> > > > > > > >  	.set_fmt = alvium_set_fmt,
> > > > > > > >  	.get_selection = alvium_get_selection,
> > > > > > > >  	.set_selection = alvium_set_selection,
> > > > > > > > -	.get_frame_interval = alvium_g_frame_interval,
> > > > > > > > +	.get_frame_interval = v4l2_subdev_get_frame_interval,
> > > > > > > >  	.set_frame_interval = alvium_s_frame_interval,
> > > > > > > >  };
> > > > > > > >  
> > > > > > > > @@ -2260,11 +2249,6 @@ static int alvium_subdev_init(struct alvium_dev *alvium)
> > > > > > > >  	struct v4l2_subdev *sd = &alvium->sd;
> > > > > > > >  	int ret;
> > > > > > > >  
> > > > > > > > -	/* Setup initial frame interval*/
> > > > > > > > -	alvium->frame_interval.numerator = 1;
> > > > > > > > -	alvium->frame_interval.denominator = ALVIUM_DEFAULT_FR_HZ;
> > > > > > > > -	alvium->fr = ALVIUM_DEFAULT_FR_HZ;
> > > > > > > > -
> > > > > > > >  	/* Setup the initial mode */
> > > > > > > >  	alvium->mode.fmt = alvium_csi2_default_fmt;
> > > > > > > >  	alvium->mode.width = alvium_csi2_default_fmt.width;
> > > > > > > > diff --git a/drivers/media/i2c/alvium-csi2.h b/drivers/media/i2c/alvium-csi2.h
> > > > > > > > index a6529b28e7dd..f5e26257b042 100644
> > > > > > > > --- a/drivers/media/i2c/alvium-csi2.h
> > > > > > > > +++ b/drivers/media/i2c/alvium-csi2.h
> > > > > > > > @@ -442,8 +442,6 @@ struct alvium_dev {
> > > > > > > >  	s32 inc_sharp;
> > > > > > > >  
> > > > > > > >  	struct alvium_mode mode;
> > > > > > > > -	struct v4l2_fract frame_interval;
> > > > > > > > -	u64 fr;
> > > > > > > 
> > > > > > > The fr field should have been removed by a previous patch (the one that
> > > > > > > will go between 1/3 an 2/3, see my review of 1/3) as shown by the fact
> > > > > > > that this patch only removes two locations where the field is set but
> > > > > > > none where it's read.
> > > > > > > 
> > > > > > > >  
> > > > > > > >  	u8 h_sup_csi_lanes;
> > > > > > > >  	u64 link_freq;
> 
> -- 
> Regards,
> 
> Laurent Pinchart