On Tuesday 29 March 2016 00:11:13, Stefan Agner wrote:

quoted

quoted

--- a/Documentation/devicetree/bindings/display/fsl,dcu.txt
+++ b/Documentation/devicetree/bindings/display/fsl,dcu.txt

@@ -14,6 +14,7 @@ Required properties:
 Optional properties:
 - clocks:		Second handle for pixel clock.
 - clock-names:		Second name "pix" for pixel clock.

+- fsl,tcon:		The phandle to the timing controller node.

Maybe a comment this is (currently) only for Vybrid, but not LS1021A.

IMHO, such references to SoCs in a peripheral binding is somewhat
misplaced. If we would start doing this, we would end up in lots of SoC
references, and nobody knows whether they are actually accurate and up
to date... And I think we should add tcon to LS1021a, more on that
below...

Well, I don't mind after all.

quoted

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--- /dev/null
+++ b/drivers/gpu/drm/fsl-dcu/fsl_tcon.c

[...]
+struct fsl_tcon *fsl_tcon_init(struct device *dev)
+{
+	struct fsl_tcon *tcon;
+	struct device_node *np;
+	int ret;
+
+	tcon = devm_kzalloc(dev, sizeof(*tcon), GFP_KERNEL);
+	if (!tcon)
+		return NULL;
+
+	np = of_parse_phandle(dev->of_node, "fsl,tcon", 0);
+	if (!np) {
+		dev_warn(dev, "Couldn't find the tcon node\n");
+		return NULL;
+	}

Maybe check for device tree node before allocating struct fsl_tcon? Also
this should not be a warning, as on LS1021A this is to be expected.

Agreed, definitely the smarter sequence.

Afact LS1021a has also a TCON. At least in Jianwei Wangs initial patches
it was part of the driver, see:
https://lkml.org/lkml/2015/7/13/242

Not sure how that driver can work without TCON support on LS1021a, maybe
the bootloader sets the TCON to bypass?

Since I do not have a LS1021a, I hesitated to just add it to the LS1021s
dt's, but it should be fairly straight forward.

Interesting, but in Patch 3 (https://lists.freedesktop.org/archives/dri-devel/2015-July/086381.html) no TCON node is added and using is still 
optional. Yet, I don't find any TCON hardware in the LS1021A reference manual, 
e.g. in the memory map. I hard guess is that it doesn't require/use one. 
Without memory address it would be pretty hard to add one.

Alexander