Hi Tomi,

On Wed, Dec 4, 2013 at 1:28 PM, Tomi Valkeinen [off-list ref] wrote:

Hi,

Here's a new version for DT support to OMAP Display Subsystem. See
http://article.gmane.org/gmane.linux.ports.arm.omap/102689 for the intro of the
previous version, which contains thoughts about the related problems.

The major change in this version is the use of V4L2 and CDF style port/endpoint
style in the DT data. However, note that even if the DT data contains proper
port & endpoint data, the drivers only use the first endpoint. This is to
simplify the patches, as adding full support for the ports and endpoints to the
drivers will be a big task. This approach still works with more or less all the
boards, as the only cases where the simpler model is an issue are the boards
with multiple display devices connected to a single output.

Laurent, I'd appreciate if you could have a look at the .dts changes, to see if
there's anything that's clearly not CDF compatible.

The patches can also be found from:
git://git.kernel.org/pub/scm/linux/kernel/git/tomba/linux.git work/dss-dt

I tested your branch on my DM3730 IGEPv2 board by cherry-picking the following
commits from latest Linus tree on top of your work/dss-dt branch:

d526daeb ("ARM: dts: omap3-igep0020: Add pinmux setup for i2c devices")
50592dc3 ("ARM: dts: omap3-igep0020: Add pinmuxing for DVI output")

And adding the display information using your DSS bindings to omap3-igep0020.dts
[0].

But it failed for me because of a probing order. The problem is that the probing
order is:

omap_i2c
pinctrl-single
OMAP DSS
connector-dvi
omapfb

Now DT good practices says that the pinmux setup needed for a device have to be
initialized in a pin control state for the device using these pins (i.e: i2c3)
instead of doing globally by being part of a pinctrl state of the pinmux device
(i.e: omap3_pmx_core).

But due this init order the omap_i2c probe is deferred due pinctrl-single not
being initialized yet:

[    0.565246] omap_i2c 48060000.i2c: could not find pctldev for node /ocp/pinmu


x@48002030/pinmux_i2c3_pins, deferring probe

This is ok since eventually the pinctrl-single driver will be initialized and
the next time the omap_i2c probe is called it will succeed. But before omap_i2c
has a chance to be probed again the connector-dvi driver is probed and fails due
the i2c bus not being initialized yet:

[    1.064300] OMAP DSS rev 2.0
[    1.073669] connector-dvi connector.12: failed to parse i2c-bus
[    1.073730] connector-dvi: probe of connector.12 failed with error -22
[    1.078216] omapfb omapfb: no displays
[    1.080871] omapfb omapfb: failed to setup omapfb
[    1.080932] platform omapfb: Driver omapfb requests probe deferral
..

Later the omap_i2c driver probe succees since the pinctrl-single driver was
initialized but by then it is already too late:

[    3.293914] omap_i2c 48070000.i2c: bus 0 rev4.4 at 2600 kHz
[    3.301940] omap_i2c 48072000.i2c: bus 1 rev4.4 at 400 kHz
[    3.310882] omap_i2c 48060000.i2c: bus 2 rev4.4 at 100 kHz
[    3.317565] omapfb omapfb: no displays
[    3.321716] omapfb omapfb: failed to setup omapfb
[    3.326751] platform omapfb: Driver omapfb requests probe deferral
..
[    3.694915] omapfb omapfb: no displays
[    3.699127] omapfb omapfb: failed to setup omapfb
[    3.704071] platform omapfb: Driver omapfb requests probe deferral
..

If I move the i2c3 pinmux definitions from the i2c3 device node to
omap3_pmx_core then the display works correctly.

So, I think that we should add deferred probing to drivers/video/omap2/*.c too
to avoid the scenario I described above.

Also, would you mind to include [0] on your patch-set so display continue
working for IGEPv2 after you remove the pdata-quirks and dss-common.c hacks?

Thanks a lot and best regards,
Javier

[0]:

From a9af54a3b63bccade241e056d153d8bf04a6a5d5 Mon Sep 17 00:00:00 2001

From: Javier Martinez Canillas <redacted>
Date: Fri, 6 Dec 2013 02:53:38 +0100
Subject: [PATCH 1/1] ARM: dts: omap3-igep0020: add display information

The IGEPv2 has a TFP410 DPI-to-DVI encoder attached
to OMAP's Display SubSystem (DSS). Add DeviceTree
nodes for these devices.

Signed-off-by: Javier Martinez Canillas <redacted>
---
 arch/arm/boot/dts/omap3-igep0020.dts | 51 ++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/arch/arm/boot/dts/omap3-igep0020.dts

b/arch/arm/boot/dts/omap3-igep0020.dts
index 76509de..2569d60 100644

--- a/arch/arm/boot/dts/omap3-igep0020.dts
+++ b/arch/arm/boot/dts/omap3-igep0020.dts

@@ -215,3 +215,54 @@
 &usbhsehci {
 	phys = <&hsusb1_phy>;
 };
+
+&dpi {
+	vdds_dsi-supply = <&vpll2>;
+
+	dpi_out: endpoint {
+		remote-endpoint = <&tfp410_in>;
+		data-lines = <24>;
+	};
+};
+
+
+/ {
+	aliases {
+		display0 = &dvi0;
+	};
+
+	tfp410: encoder@0 {
+		compatible = "ti,tfp410";
+		gpios = <&gpio6 10 GPIO_ACTIVE_HIGH>; /* 170, power-down */
+
+		ports {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			port@0 {
+				reg = <0>;
+
+				tfp410_in: endpoint@0 {
+					remote-endpoint = <&dpi_out>;
+				};
+			};
+
+			port@1 {
+				reg = <1>;
+
+				tfp410_out: endpoint@1 {
+					remote-endpoint = <&dvi_connector_in>;
+				};
+			};
+		};
+	};
+
+	dvi0: connector@0 {
+		compatible = "ti,dvi-connector";
+		i2c-bus = <&i2c3>;
+
+		dvi_connector_in: endpoint {
+			remote-endpoint = <&tfp410_out>;
+		};
+	};
+};

-- 
1.8.4.2