[V7,03/12] drm/bridge: Add helper functions for drm_bridge

Commit Message

Russell King - ARM Linux Oct. 27, 2014, 11:57 p.m. UTC

On Mon, Oct 27, 2014 at 11:26:30PM +0100, Daniel Vetter wrote:
> Looking at the of_drm_find_panel function I actually wonder how that
> works - the drm_panel doesn't really need to stick around afaics.
> After all panel_list is global so some other driver can unload.
> Russell's of support for possible_crtcs code works differently since
> it only looks at per-drm_device lists.
> 
> This bridge code here though suffers from the same. So to me this
> looks rather fishy.
> 
> It doesn't help that we have drm_of.[hc] around but not all the of
> code is in there. Adding Russell too.

I rather dropped the ball with imx-drm when things became difficult with
asking Greg to pull my git tree - and as a result, I decided that I would
no longer be helping with patch submission for imx-drm, nor trying to get
it out of the staging tree anymore.

I do still have the patch (dated from July) in my git tree which adds it
to imx-drm - see below.  Rebased to 3.18-rc2 today.

I also have a patch (from April) which creates a generic OF DDC connector
helper, but that remains unfinished, in the sense that it lives beside
imx-drm, pulling the DDC specific code out of imx-hdmi and imx-tve, even
though there's nothing imx-drm specific about it.

8<====
From: Russell King <[e-mail]>
Subject: [PATCH] imx-drm: convert imx-drm to use the generic DRM OF helper

Use the generic DRM OF helper to locate the possible CRTCs for the
encoder, thereby shrinking the imx-drm driver some more.

Acked-by: Philipp Zabel <[e-mail]>
Signed-off-by: Russell King <[e-mail]>
---
 drivers/staging/imx-drm/imx-drm-core.c | 72 ++++++----------------------------
 1 file changed, 13 insertions(+), 59 deletions(-)

Comments

Philipp Zabel Nov. 4, 2014, 9:22 a.m. UTC | #1

Hi Russell,

Am Montag, den 27.10.2014, 23:57 +0000 schrieb Russell King - ARM Linux:
> On Mon, Oct 27, 2014 at 11:26:30PM +0100, Daniel Vetter wrote:
> > Looking at the of_drm_find_panel function I actually wonder how that
> > works - the drm_panel doesn't really need to stick around afaics.
> > After all panel_list is global so some other driver can unload.
> > Russell's of support for possible_crtcs code works differently since
> > it only looks at per-drm_device lists.
> > 
> > This bridge code here though suffers from the same. So to me this
> > looks rather fishy.
> > 
> > It doesn't help that we have drm_of.[hc] around but not all the of
> > code is in there. Adding Russell too.
> 
> I rather dropped the ball with imx-drm when things became difficult with
> asking Greg to pull my git tree - and as a result, I decided that I would
> no longer be helping with patch submission for imx-drm, nor trying to get
> it out of the staging tree anymore.

In that case I'd like to take up the ball.

In my opinion the driver is now in a state in which it could be moved to
gpu/drm first and then fixed up there (all the blockers in
drivers/staging/imx-drm/TODO are gone). That would also give us a single
path for all imx-drm/ipu-v3 related patches again. My main motivation to
put it into staging in the first place was that the device tree bindings
had to be worked out, but now it only results in a coordination
nightmare.

regards
Philipp

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Patch

diff --git a/drivers/staging/imx-drm/imx-drm-core.c b/drivers/staging/imx-drm/imx-drm-core.c
index 9cb222e2996f..5e2c1f4b9165 100644
--- a/drivers/staging/imx-drm/imx-drm-core.c
+++ b/drivers/staging/imx-drm/imx-drm-core.c
@@ -24,6 +24,7 @@ 
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_gem_cma_helper.h>
 #include <drm/drm_fb_cma_helper.h>
+#include <drm/drm_of.h>
 
 #include "imx-drm.h"
 
@@ -47,7 +48,6 @@  struct imx_drm_crtc {
 	struct drm_crtc				*crtc;
 	int					pipe;
 	struct imx_drm_crtc_helper_funcs	imx_drm_helper_funcs;
-	struct device_node			*port;
 };
 
 static int legacyfb_depth = 16;
@@ -366,9 +366,10 @@  int imx_drm_add_crtc(struct drm_device *drm, struct drm_crtc *crtc,
 
 	imx_drm_crtc->imx_drm_helper_funcs = *imx_drm_helper_funcs;
 	imx_drm_crtc->pipe = imxdrm->pipes++;
-	imx_drm_crtc->port = port;
 	imx_drm_crtc->crtc = crtc;
 
+	crtc->port = port;
+
 	imxdrm->crtc[imx_drm_crtc->pipe] = imx_drm_crtc;
 
 	*new_crtc = imx_drm_crtc;
@@ -409,34 +410,6 @@  int imx_drm_remove_crtc(struct imx_drm_crtc *imx_drm_crtc)
 }
 EXPORT_SYMBOL_GPL(imx_drm_remove_crtc);
 
-/*
- * Find the DRM CRTC possible mask for the connected endpoint.
- *
- * The encoder possible masks are defined by their position in the
- * mode_config crtc_list.  This means that CRTCs must not be added
- * or removed once the DRM device has been fully initialised.
- */
-static uint32_t imx_drm_find_crtc_mask(struct imx_drm_device *imxdrm,
-	struct device_node *endpoint)
-{
-	struct device_node *port;
-	unsigned i;
-
-	port = of_graph_get_remote_port(endpoint);
-	if (!port)
-		return 0;
-	of_node_put(port);
-
-	for (i = 0; i < MAX_CRTC; i++) {
-		struct imx_drm_crtc *imx_drm_crtc = imxdrm->crtc[i];
-
-		if (imx_drm_crtc && imx_drm_crtc->port == port)
-			return drm_crtc_mask(imx_drm_crtc->crtc);
-	}
-
-	return 0;
-}
-
 static struct device_node *imx_drm_of_get_next_endpoint(
 		const struct device_node *parent, struct device_node *prev)
 {
@@ -449,35 +422,16 @@  static struct device_node *imx_drm_of_get_next_endpoint(
 int imx_drm_encoder_parse_of(struct drm_device *drm,
 	struct drm_encoder *encoder, struct device_node *np)
 {
-	struct imx_drm_device *imxdrm = drm->dev_private;
-	struct device_node *ep = NULL;
-	uint32_t crtc_mask = 0;
-	int i;
+	uint32_t crtc_mask = drm_of_find_possible_crtcs(drm, np);
 
-	for (i = 0; ; i++) {
-		u32 mask;
-
-		ep = imx_drm_of_get_next_endpoint(np, ep);
-		if (!ep)
-			break;
-
-		mask = imx_drm_find_crtc_mask(imxdrm, ep);
-
-		/*
-		 * If we failed to find the CRTC(s) which this encoder is
-		 * supposed to be connected to, it's because the CRTC has
-		 * not been registered yet.  Defer probing, and hope that
-		 * the required CRTC is added later.
-		 */
-		if (mask == 0)
-			return -EPROBE_DEFER;
-
-		crtc_mask |= mask;
-	}
-
-	of_node_put(ep);
-	if (i == 0)
-		return -ENOENT;
+	/*
+	 * If we failed to find the CRTC(s) which this encoder is
+	 * supposed to be connected to, it's because the CRTC has
+	 * not been registered yet.  Defer probing, and hope that
+	 * the required CRTC is added later.
+	 */
+	if (crtc_mask == 0)
+		return -EPROBE_DEFER;
 
 	encoder->possible_crtcs = crtc_mask;
 
@@ -511,7 +465,7 @@  int imx_drm_encoder_get_mux_id(struct device_node *node,
 
 		port = of_graph_get_remote_port(ep);
 		of_node_put(port);
-		if (port == imx_crtc->port) {
+		if (port == imx_crtc->crtc->port) {
 			ret = of_graph_parse_endpoint(ep, &endpoint);
 			return ret ? ret : endpoint.port;
 		}