Re: [PATCH v3 10/24] drm/sun4i: tcon: Generalize engine search algorithm

Maxime Ripard
2018-06-28T18:25:43Z

On Thu, Jun 28, 2018 at 06:48:50AM +0200, Jernej Škrabec wrote:
> Dne četrtek, 28. junij 2018 ob 04:06:52 CEST je Chen-Yu Tsai napisal(a):
> > On Mon, Jun 25, 2018 at 8:02 PM, Jernej Skrabec <jernej.skrabec@siol.net>
> wrote:
> > > Current "old" method to find engine worked pretty well for DE2. However,
> > > it doesn't work when TCON TOP is between mixer (engine) and TCON. TCON
> > > TOP has multiple input ports, but current engine search algorithm
> > > expects only one.
> > >
> > > This can be fixed by first looking for output port id and selecting
> > > matching input by subtracting 1 for the next round. This work even if
> > > there is only one input and output.
> > >
> > > Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
> > > ---
> > >
> > > drivers/gpu/drm/sun4i/sun4i_tcon.c | 22 ++++++++++++++++++----
> > > 1 file changed, 18 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c
> > > b/drivers/gpu/drm/sun4i/sun4i_tcon.c index 08747fc3ee71..264bcc43da11
> > > 100644
> > > --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
> > > +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
> > > @@ -791,12 +791,14 @@ static int sun4i_tcon_init_regmap(struct device
> > > *dev,
> > >
> > > */
> > >
> > > static struct sunxi_engine *
> > > sun4i_tcon_find_engine_traverse(struct sun4i_drv *drv,
> > >
> > > - struct device_node *node)
> > > + struct device_node *node,
> > > + u32 port_id)
> > >
> > > {
> > >
> > > struct device_node *port, *ep, *remote;
> > > struct sunxi_engine *engine = ERR_PTR(-EINVAL);
> > >
> > > + u32 reg = 0;
> > >
> > > - port = of_graph_get_port_by_id(node, 0);
> > > + port = of_graph_get_port_by_id(node, port_id);
> > >
> > > if (!port)
> > >
> > > return ERR_PTR(-EINVAL);
> > >
> > > @@ -826,8 +828,20 @@ sun4i_tcon_find_engine_traverse(struct sun4i_drv
> > > *drv,
> > >
> > > if (remote == engine->node)
> > >
> > > goto out_put_remote;
> > >
> > > + /*
> > > + * According to device tree binding input ports have even id
> > > + * number and output ports have odd id. Since component with
> > > + * more than one input and one output (TCON TOP) exits, correct
> > > + * remote input id has to be calculated by subtracting 1 from
> > > + * remote output id. If this for some reason can't be done, 0
> > > + * is used as input port id.
> > > + */
> >
> > You need to call
> >
> > of_node_put(port);
> >
> > to drop the reference to the original port.
>
> Thanks for noticing it. I guess I should send fix patch, since patches from
> drm-misc-next can't be dropped.

Yeah, please send additional patches for all the issues pointed out by
Chen-Yu.

Maxime

--
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com
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