linux-kernel - Re: [RFC PATCH 03/11] drm: sun4i: ignore swapped mixer<->tcon connection for DE2

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Message-ID: <20170524081440.cbtjvvmj5okrri6z@flea.home>
Date:   Wed, 24 May 2017 10:14:40 +0200
From:   Maxime Ripard <maxime.ripard@...e-electrons.com>
To:     Icenowy Zheng <icenowy@...c.io>
Cc:     Rob Herring <robh+dt@...nel.org>, Chen-Yu Tsai <wens@...e.org>,
        dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-clk@...r.kernel.org, linux-sunxi@...glegroups.com
Subject: Re: [RFC PATCH 03/11] drm: sun4i: ignore swapped mixer<->tcon
 connection for DE2

On Sat, May 20, 2017 at 02:00:22AM +0800, Icenowy Zheng wrote:
> 
> 
> 于 2017年5月20日 GMT+08:00 上午1:57:53, Maxime Ripard <maxime.ripard@...e-electrons.com> 写到:
> >On Thu, May 18, 2017 at 12:43:46AM +0800, Icenowy Zheng wrote:
> >> Some SoC's DE2 has two mixers. Defaultly the mixer0 is connected to
> >> tcon0 and mixer1 is connected to tcon1; however by setting a bit
> >> the connection can be swapped.
> >> 
> >> As we now hardcode the default connection, ignore the bonus endpoint
> >for
> >> the mixer's output and the TCON's input, as they stands for the
> >swapped
> >> connection.
> >> 
> >> Signed-off-by: Icenowy Zheng <icenowy@...c.io>
> >> ---
> >>  drivers/gpu/drm/sun4i/sun4i_drv.c  | 27 ++++++++++++++++++++++++++
> >>  drivers/gpu/drm/sun4i/sun4i_tcon.c | 39
> >+++++++++++++++++++++++++++++---------
> >>  drivers/gpu/drm/sun4i/sun4i_tcon.h |  2 ++
> >>  3 files changed, 59 insertions(+), 9 deletions(-)
> >> 
> >> diff --git a/drivers/gpu/drm/sun4i/sun4i_drv.c
> >b/drivers/gpu/drm/sun4i/sun4i_drv.c
> >> index 1dd1948025d2..29bf1325ded6 100644
> >> --- a/drivers/gpu/drm/sun4i/sun4i_drv.c
> >> +++ b/drivers/gpu/drm/sun4i/sun4i_drv.c
> >> @@ -173,6 +173,13 @@ static bool sun4i_drv_node_is_frontend(struct
> >device_node *node)
> >>  		of_device_is_compatible(node,
> >"allwinner,sun8i-a33-display-frontend");
> >>  }
> >>  
> >> +static bool sun4i_drv_node_is_swappable_de2_mixer(struct device_node
> >*node)
> >> +{
> >> +	/* The V3s has only one mixer-tcon pair, so it's not listed here.
> >*/
> >> +	return of_device_is_compatible(node,
> >"allwinner,sun8i-h3-de2-mixer0") ||
> >> +		of_device_is_compatible(node, "allwinner,sun8i-h3-de2-mixer1");
> >> +}
> >> +
> >>  static bool sun4i_drv_node_is_tcon(struct device_node *node)
> >>  {
> >>  	return of_device_is_compatible(node, "allwinner,sun5i-a13-tcon") ||
> >> @@ -249,6 +256,26 @@ static int sun4i_drv_add_endpoints(struct device
> >*dev,
> >>  			}
> >>  		}
> >>  
> >> +		/*
> >> +		 * The second endpoint of the output of a swappable DE2 mixer
> >> +		 * is the TCON after connection swapping.
> >> +		 * Ignore it now, as we now hardcode mixer0->tcon0,
> >> +		 * mixer1->tcon1 connection.
> >> +		 */
> >> +		if (sun4i_drv_node_is_swappable_de2_mixer(node)) {
> >> +			struct of_endpoint endpoint;
> >> +
> >> +			if (of_graph_parse_endpoint(ep, &endpoint)) {
> >> +				DRM_DEBUG_DRIVER("Couldn't parse endpoint\n");
> >> +				continue;
> >> +			}
> >> +
> >> +			if (endpoint.id) {
> >> +				DRM_DEBUG_DRIVER("Endpoint is an unused connection for DE2
> >mixer... skipping\n");
> >> +				continue;
> >> +			}
> >> +		}
> >> +
> >>  		/* Walk down our tree */
> >>  		count += sun4i_drv_add_endpoints(dev, match, remote);
> >>  
> >> diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c
> >b/drivers/gpu/drm/sun4i/sun4i_tcon.c
> >> index f44a37a5993d..89a215ff2370 100644
> >> --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
> >> +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
> >> @@ -425,7 +425,8 @@ static int sun4i_tcon_init_regmap(struct device
> >*dev,
> >>   * requested via the get_id function of the engine.
> >>   */
> >>  static struct sunxi_engine *sun4i_tcon_find_engine(struct sun4i_drv
> >*drv,
> >> -						   struct device_node *node)
> >> +						   struct device_node *node,
> >> +						   bool skip_bonus_ep)
> >>  {
> >>  	struct device_node *port, *ep, *remote;
> >>  	struct sunxi_engine *engine;
> >> @@ -439,6 +440,20 @@ static struct sunxi_engine
> >*sun4i_tcon_find_engine(struct sun4i_drv *drv,
> >>  		if (!remote)
> >>  			continue;
> >>  
> >> +		if (skip_bonus_ep) {
> >> +			struct of_endpoint endpoint;
> >> +
> >> +			if (of_graph_parse_endpoint(ep, &endpoint)) {
> >> +				DRM_DEBUG_DRIVER("Couldn't parse endpoint\n");
> >> +				continue;
> >> +			}
> >> +
> >> +			if (endpoint.id) {
> >> +				DRM_DEBUG_DRIVER("Skipping bonus mixer->TCON connection when
> >searching engine\n");
> >> +				continue;
> >> +			}
> >> +		}
> >> +
> >
> >You don't list the mixers in the tcon's output, why do you need that
> >exactly?
> 
> Mixers are TCONs' input, not output...

Then why are they even parsed? The whole parsing logic in the driver
only searches for output nodes.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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