Hi Sakari,
On Mon, Jun 15, 2020 at 11:34:06AM +0300, Sakari Ailus wrote:
> Hi Jacopo,
>
> On Thu, Jun 11, 2020 at 06:16:51PM +0200, Jacopo Mondi wrote:
> > Use the newly introduced get_mbus_config() subdevice pad operation to
> > retrieve the remote subdevice MIPI CSI-2 bus configuration and configure
> > the number of active data lanes accordingly.
> >
> > In order to be able to call the remote subdevice operation cache the
> > index of the remote pad connected to the single CSI-2 input port.
> >
> > Signed-off-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
> > ---
> > drivers/media/platform/rcar-vin/rcar-csi2.c | 61 ++++++++++++++++++++-
> > 1 file changed, 58 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c b/drivers/media/platform/rcar-vin/rcar-csi2.c
> > index 151e6a90c5fb..11769f004fd8 100644
> > --- a/drivers/media/platform/rcar-vin/rcar-csi2.c
> > +++ b/drivers/media/platform/rcar-vin/rcar-csi2.c
> > @@ -363,6 +363,7 @@ struct rcar_csi2 {
> > struct v4l2_async_notifier notifier;
> > struct v4l2_async_subdev asd;
> > struct v4l2_subdev *remote;
> > + unsigned int remote_pad;
> >
> > struct v4l2_mbus_framefmt mf;
> >
> > @@ -371,6 +372,7 @@ struct rcar_csi2 {
> >
> > unsigned short lanes;
> > unsigned char lane_swap[4];
> > + unsigned short active_lanes;
>
> Do you need this? I.e. should you not always request this from the
> transmitter device?
It's actually the other way around. The receiver queries the
transmitter to know how many data lanes it intends to use and adjusts
its configuration to accommodate it.
>
> > };
> >
> > static inline struct rcar_csi2 *sd_to_csi2(struct v4l2_subdev *sd)
> > @@ -414,7 +416,7 @@ static int rcsi2_wait_phy_start(struct rcar_csi2 *priv)
> >
> > /* Wait for the clock and data lanes to enter LP-11 state. */
> > for (timeout = 0; timeout <= 20; timeout++) {
> > - const u32 lane_mask = (1 << priv->lanes) - 1;
> > + const u32 lane_mask = (1 << priv->active_lanes) - 1;
> >
> > if ((rcsi2_read(priv, PHCLM_REG) & PHCLM_STOPSTATECKL) &&
> > (rcsi2_read(priv, PHDLM_REG) & lane_mask) == lane_mask)
> > @@ -471,11 +473,57 @@ static int rcsi2_calc_mbps(struct rcar_csi2 *priv, unsigned int bpp)
> > * bps = link_freq * 2
> > */
> > mbps = v4l2_ctrl_g_ctrl_int64(ctrl) * bpp;
> > - do_div(mbps, priv->lanes * 1000000);
> > + do_div(mbps, priv->active_lanes * 1000000);
> >
> > return mbps;
> > }
> >
> > +static int rcsi2_config_active_lanes(struct rcar_csi2 *priv)
> > +{
> > + struct v4l2_mbus_config mbus_config = { 0 };
> > + unsigned int num_lanes = (-1U);
> > + int ret;
> > +
> > + priv->active_lanes = priv->lanes;
> > + ret = v4l2_subdev_call(priv->remote, pad, get_mbus_config,
> > + priv->remote_pad, &mbus_config);
> > + if (ret == -ENOIOCTLCMD) {
> > + dev_dbg(priv->dev, "No remote mbus configuration available\n");
> > + return 0;
> > + }
> > +
> > + if (ret) {
> > + dev_err(priv->dev, "Failed to get remote mbus configuration\n");
> > + return ret;
> > + }
> > +
> > + if (mbus_config.type != V4L2_MBUS_CSI2_DPHY) {
> > + dev_err(priv->dev, "Unsupported media bus type %u\n",
> > + mbus_config.type);
> > + return -EINVAL;
> > + }
> > +
> > + if (mbus_config.flags & V4L2_MBUS_CSI2_1_LANE)
> > + num_lanes = 1;
> > + else if (mbus_config.flags & V4L2_MBUS_CSI2_2_LANE)
> > + num_lanes = 2;
> > + else if (mbus_config.flags & V4L2_MBUS_CSI2_3_LANE)
> > + num_lanes = 3;
> > + else if (mbus_config.flags & V4L2_MBUS_CSI2_4_LANE)
> > + num_lanes = 4;
>
> This is the downside of using flags... Anyway, I guess this is certainly
> fine now.
>
Let's change this on top, if we like to (and I would like to :)
Thanks
j
> > +
> > + if (num_lanes > priv->lanes) {
> > + dev_err(priv->dev,
> > + "Unsupported mbus config: too many data lanes %u\n",
> > + num_lanes);
> > + return -EINVAL;
> > + }
> > +
> > + priv->active_lanes = num_lanes;
> > +
> > + return 0;
> > +}
> > +
> > static int rcsi2_start_receiver(struct rcar_csi2 *priv)
> > {
> > const struct rcar_csi2_format *format;
> > @@ -490,6 +538,11 @@ static int rcsi2_start_receiver(struct rcar_csi2 *priv)
> > /* Code is validated in set_fmt. */
> > format = rcsi2_code_to_fmt(priv->mf.code);
> >
> > + /* Get the remote mbus config to get the number of enabled lanes. */
> > + ret = rcsi2_config_active_lanes(priv);
> > + if (ret)
> > + return ret;
> > +
> > /*
> > * Enable all supported CSI-2 channels with virtual channel and
> > * data type matching.
> > @@ -522,7 +575,7 @@ static int rcsi2_start_receiver(struct rcar_csi2 *priv)
> > }
> >
> > phycnt = PHYCNT_ENABLECLK;
> > - phycnt |= (1 << priv->lanes) - 1;
> > + phycnt |= (1 << priv->active_lanes) - 1;
> >
> > mbps = rcsi2_calc_mbps(priv, format->bpp);
> > if (mbps < 0)
> > @@ -748,6 +801,7 @@ static int rcsi2_notify_bound(struct v4l2_async_notifier *notifier,
> > }
> >
> > priv->remote = subdev;
> > + priv->remote_pad = pad;
> >
> > dev_dbg(priv->dev, "Bound %s pad: %d\n", subdev->name, pad);
> >
> > @@ -793,6 +847,7 @@ static int rcsi2_parse_v4l2(struct rcar_csi2 *priv,
> > priv->lanes);
> > return -EINVAL;
> > }
> > + priv->active_lanes = priv->lanes;
> >
> > for (i = 0; i < ARRAY_SIZE(priv->lane_swap); i++) {
> > priv->lane_swap[i] = i < priv->lanes ?
>
> --
> Kind regards,
>
> Sakari Ailus
