Hi Kieran,
On Tue, Dec 11, 2018 at 11:07:09PM +0000, Kieran Bingham wrote:
> Hi Jacopo,
>
> Thank you for the patch,
>
> On 11/12/2018 15:16, Jacopo Mondi wrote:
> > The ADV748x chip supports routing AFE output to either TXA or TXB.
> > In order to support run-time configuration of video stream path, create an
> > additional (not enabled) "AFE:8->TXA:0" link, and remove the IMMUTABLE flag
> > from existing ones.
> >
> > Signed-off-by: Jacopo Mondi <jacopo+rene...@jmondi.org>
> > ---
> > drivers/media/i2c/adv748x/adv748x-csi2.c | 48
> > ++++++++++++++++++++------------
> > 1 file changed, 30 insertions(+), 18 deletions(-)
> >
> > diff --git a/drivers/media/i2c/adv748x/adv748x-csi2.c
> > b/drivers/media/i2c/adv748x/adv748x-csi2.c
> > index 6ce21542ed48..4d1aefc2c8d0 100644
> > --- a/drivers/media/i2c/adv748x/adv748x-csi2.c
> > +++ b/drivers/media/i2c/adv748x/adv748x-csi2.c
> > @@ -27,6 +27,7 @@ static int adv748x_csi2_set_virtual_channel(struct
> > adv748x_csi2 *tx,
> > * @v4l2_dev: Video registration device
> > * @src: Source subdevice to establish link
> > * @src_pad: Pad number of source to link to this @tx
> > + * @flags: Flags for the newly created link
> > *
> > * Ensure that the subdevice is registered against the v4l2_device, and
> > link the
> > * source pad to the sink pad of the CSI2 bus entity.
> > @@ -34,17 +35,11 @@ static int adv748x_csi2_set_virtual_channel(struct
> > adv748x_csi2 *tx,
> > static int adv748x_csi2_register_link(struct adv748x_csi2 *tx,
> > struct v4l2_device *v4l2_dev,
> > struct v4l2_subdev *src,
> > - unsigned int src_pad)
> > + unsigned int src_pad,
> > + unsigned int flags)
> > {
> > - int enabled = MEDIA_LNK_FL_ENABLED;
> > int ret;
> >
> > - /*
> > - * Dynamic linking of the AFE is not supported.
> > - * Register the links as immutable.
> > - */
> > - enabled |= MEDIA_LNK_FL_IMMUTABLE;
> > -
>
> Yup - that part certainly needs to go ...
>
> > if (!src->v4l2_dev) {
> > ret = v4l2_device_register_subdev(v4l2_dev, src);
> > if (ret)
> > @@ -53,7 +48,7 @@ static int adv748x_csi2_register_link(struct adv748x_csi2
> > *tx,
> >
> > return media_create_pad_link(&src->entity, src_pad,
> > &tx->sd.entity, ADV748X_CSI2_SINK,
> > - enabled);
> > + flags);
> > }
> >
> > /*
> > -----------------------------------------------------------------------------
> > @@ -68,24 +63,41 @@ static int adv748x_csi2_registered(struct v4l2_subdev
> > *sd)
> > {
> > struct adv748x_csi2 *tx = adv748x_sd_to_csi2(sd);
> > struct adv748x_state *state = tx->state;
> > + int ret;
> >
> > adv_dbg(state, "Registered %s (%s)", is_txa(tx) ? "TXA":"TXB",
> > sd->name);
> >
> > /*
> > - * The adv748x hardware allows the AFE to route through the TXA, however
> > - * this is not currently supported in this driver.
> > + * Link TXA to HDMI and AFE, and TXB to AFE only as TXB cannot output
> > + * HDMI.
> > *
> > - * Link HDMI->TXA, and AFE->TXB directly.
> > + * The HDMI->TXA link is enabled by default, as the AFE->TXB is.
> > */
> > - if (is_txa(tx) && is_hdmi_enabled(state))
> > - return adv748x_csi2_register_link(tx, sd->v4l2_dev,
> > - &state->hdmi.sd,
> > - ADV748X_HDMI_SOURCE);
> > - if (!is_txa(tx) && is_afe_enabled(state))
> > + if (is_txa(tx)) {
> > + if (is_hdmi_enabled(state)) {
> > + ret = adv748x_csi2_register_link(tx, sd->v4l2_dev,
> > + &state->hdmi.sd,
> > + ADV748X_HDMI_SOURCE,
> > + MEDIA_LNK_FL_ENABLED);
> > + if (ret)
> > + return ret;
> > + }
> > +
> > + if (is_afe_enabled(state)) {
> > + ret = adv748x_csi2_register_link(tx, sd->v4l2_dev,
> > + &state->afe.sd,
> > + ADV748X_AFE_SOURCE,
> > + 0);
> > + if (ret)
> > + return ret;
> > + }
>
>
> > + } else if (is_afe_enabled(state))
>
> I believe when adding braces to one side of an if statement, we are
> supposed to add to the else clauses too ?
Correct
>
> > return adv748x_csi2_register_link(tx, sd->v4l2_dev,
> > &state->afe.sd,
> > - ADV748X_AFE_SOURCE);
> > + ADV748X_AFE_SOURCE,
> > + MEDIA_LNK_FL_ENABLED);
>
> Won't this enable the AFE link for both TXA and TXB ?
> Which one will win? Just the last one ? the first one ?
> Does it error?
>
> (It might not be a problem ... I can't recall what the behaviour is)
>
>
The AFE->TXA link is created as not enabled (see the 0 as last
argument in the adv748x_csi2_register_link() call above here, in the
'is_txa(tx)' case
> > +
>
> There are a lot of nested if's above, and I think we can simplify
> greatly if we move the logic for the flags inside
> adv748x_csi2_register_link(), and adjust the checks on is_xxx_enabled()
>
> What do you think about the following pseudo code?:
>
>
> int adv748x_csi2_register_link(struct adv748x_csi2 *tx,
> struct v4l2_device *v4l2_dev,
> struct v4l2_subdev *src,
> unsigned int src_pad,
> bool enable)
> {
>
> int flags = 0;
> int ret;
>
> if (!src->v4l2_dev) {
> ret = v4l2_device_register_subdev(v4l2_dev, src)
> if (ret) return ret;
> }
>
> if (enable)
> flags = MEDIA_LNK_FL_ENABLED;
>
> return media_create_pad_link(&src->entity, src_pad,
> &tx->sd.entity, ADV748X_CSI2_SINK,
> flags);
> }
>
> int adv748x_csi2_registered(struct v4l2_subdev *sd)
> {
> int ret;
>
> if (is_afe_enabled(state) {
> ret = adv748x_csi2_register_link(tx, sd->v4l2_dev, &state->afe.sd,
> ADV748X_AFE_SOURCE, !is_txa(tx));
> if (ret)
> return ret;
> }
>
> /* TX-B only supports AFE */
> if (!is_txa(tx) || !(is_hdmi_enabled(state))
> return 0;
>
> return adv748x_csi2_register_link(tx, sd->v4l2_dev, &state->hdmi.sd,
> ADV748X_HDMI_SOURCE, true);
> }
>
>
> The above will for TXA:
> register_link(..., AFE_SOURCE, enable = false );
> register_link(..., HDMI_SOURCE, enable = true );
>
> then TXB:
> register_link(..., AFE_SOURCE, enable = true );
>
> Does that meet our needs?
>
Yes it does, and it looks better. Thanks!
>
>
>
> > return 0;
> > }
> >
> > --
> > 2.7.4
> >
>
> --
> Regards
> --
> Kieran
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