Hi Kieran,
On Fri, Apr 10, 2020 at 08:51:21AM +0100, Kieran Bingham wrote:
> On 09/04/2020 17:29, Jacopo Mondi wrote:
> > Hi Kieran,
> >
> > On Thu, Apr 09, 2020 at 01:11:59PM +0100, Kieran Bingham wrote:
> >> Determine the (CSI2) pixel rate control by providing a control to read,
> >> and checking the rate from the upstream camera sensors, and their
> >> appropriate formats.
> >>
> >> Signed-off-by: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx>
> >> ---
> >> drivers/media/i2c/max9286.c | 44 ++++++++++++++++++++++++++++++++-----
> >> 1 file changed, 38 insertions(+), 6 deletions(-)
> >>
> >> diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c
> >> index 17830c362a50..008a93910300 100644
> >> --- a/drivers/media/i2c/max9286.c
> >> +++ b/drivers/media/i2c/max9286.c
> >> @@ -155,6 +155,7 @@ struct max9286_priv {
> >> bool mux_open;
> >>
> >> struct v4l2_ctrl_handler ctrls;
> >> + struct v4l2_ctrl *pixelrate;
> >>
> >> struct v4l2_mbus_framefmt fmt[MAX9286_N_SINKS];
> >>
> >> @@ -631,6 +632,16 @@ static int max9286_s_stream(struct v4l2_subdev *sd, int enable)
> >> return 0;
> >> }
> >>
> >> +static int max9286_set_pixelrate(struct max9286_priv *priv, s64 rate)
> >> +{
> >> + if (!priv->pixelrate)
> >> + return -EINVAL;
> >
> > Can this happen ?
>
> Hrm ... no because the control is registered when we register the V4L2
> device, - so there can't be an occasion where we don't have it :-)
>
> Removing and simplifying.
>
> >
> >> +
> >> + dev_err(&priv->client->dev, "Setting pixel rate to %lld\n", rate);
> >
> > Is this an error ?
>
>
> Oops - debug print failure :-)
>
> I can just drop this line.
>
>
> >> +
> >> + return v4l2_ctrl_s_ctrl_int64(priv->pixelrate, rate);
> >> +}
> >> +
> >> static int max9286_enum_mbus_code(struct v4l2_subdev *sd,
> >> struct v4l2_subdev_pad_config *cfg,
> >> struct v4l2_subdev_mbus_code_enum *code)
> >> @@ -664,6 +675,7 @@ static int max9286_set_fmt(struct v4l2_subdev *sd,
> >> {
> >> struct max9286_priv *priv = sd_to_max9286(sd);
> >> struct v4l2_mbus_framefmt *cfg_fmt;
> >> + s64 pixelrate;
> >>
> >> if (format->pad >= MAX9286_SRC_PAD)
> >> return -EINVAL;
> >> @@ -688,6 +700,12 @@ static int max9286_set_fmt(struct v4l2_subdev *sd,
> >> *cfg_fmt = format->format;
> >> mutex_unlock(&priv->mutex);
> >>
> >> + /* Update pixel rate for the CSI2 receiver */
> >> + pixelrate = cfg_fmt->width * cfg_fmt->height
> >> + * priv->nsources * 30 /*FPS*/;
> >> +
> >> + max9286_set_pixelrate(priv, pixelrate);
> >> +
> >> return 0;
> >> }
> >>
> >> @@ -756,6 +774,20 @@ static const struct v4l2_subdev_internal_ops max9286_subdev_internal_ops = {
> >> .open = max9286_open,
> >> };
> >>
> >> +static int max9286_s_ctrl(struct v4l2_ctrl *ctrl)
> >> +{
> >> + switch (ctrl->id) {
> >> + case V4L2_CID_PIXEL_RATE:
> >> + return 0;
> >> + default:
> >> + return -EINVAL;
> >> + }
> >> +}
> >> +
> >> +static const struct v4l2_ctrl_ops max9286_ctrl_ops = {
> >> + .s_ctrl = max9286_s_ctrl,
> >> +};
> >> +
> >
> > After -years- I still don't get controls fully... Where is get? that's
> > the whole point of calculating the pixel rate to report it to the
> > receiver... I would not allow setting this from the extern but just
> > retrieve it after it has been updated by a set_format().
> >
> > Am I getting controls wrong again ?
>
> The control framework handles get. The value is stored in the
> priv->pixelrate control structure or managed by the core.
Ok, I keep being confused on which part are handled by the core for
controls...
>
> The CSI2 receiver calls the get operation on this subdev to know what
> the rate is for the CSI2 link, see:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/kbingham/rcar.git/tree/drivers/media/platform/rcar-vin/rcar-csi2.c?h=gmsl/dev#n449
>
Yeah that part's clear!
Thanks for clarifying this
> >
> >> static int max9286_v4l2_register(struct max9286_priv *priv)
> >> {
> >> struct device *dev = &priv->client->dev;
> >> @@ -777,12 +809,12 @@ static int max9286_v4l2_register(struct max9286_priv *priv)
> >> priv->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> >>
> >> v4l2_ctrl_handler_init(&priv->ctrls, 1);
> >> - /*
> >> - * FIXME: Compute the real pixel rate. The 50 MP/s value comes from the
> >> - * hardcoded frequency in the BSP CSI-2 receiver driver.
> >> - */
> >> - v4l2_ctrl_new_std(&priv->ctrls, NULL, V4L2_CID_PIXEL_RATE,
> >> - 50000000, 50000000, 1, 50000000);
> >> +
> >> + priv->pixelrate = v4l2_ctrl_new_std(&priv->ctrls,
> >> + &max9286_ctrl_ops,
> >> + V4L2_CID_PIXEL_RATE,
> >> + 1, INT_MAX, 1, 50000000);
> >> +
> >> priv->sd.ctrl_handler = &priv->ctrls;
> >> ret = priv->ctrls.error;
> >> if (ret)
> >> --
> >> 2.20.1
> >>
>
