[PATCH v2 0/7] drm/exynos: add pm runtime support
Inki Dae
inki.dae at samsung.com
Mon Nov 23 08:47:50 PST 2015
2015-11-23 21:25 GMT+09:00 Javier Martinez Canillas <javier at osg.samsung.com>:
> Hello,
>
> On 11/21/2015 11:59 AM, Inki Dae wrote:
>> Hi Daniel,
>>
>>
>> 2015-11-21 22:40 GMT+09:00 Daniel Stone <daniel at fooishbar.org>:
>>> Hi Inki,
>>>
>>> On 21 November 2015 at 09:38, Inki Dae <daeinki at gmail.com> wrote:
>>>> 2015-11-21 1:44 GMT+09:00 Javier Martinez Canillas <javier at osg.samsung.com>:
>>>>> On 11/20/2015 08:13 AM, Inki Dae wrote:
>>>>>> The boot log says,
>>>>>> [ 5.754493] vdd_ldo9: supplied by vdd_2v
>>>>>> [ 5.765510] of_graph_get_next_endpoint(): no port node found in /dp-controller at 145B0000
>>>>>>
>>>>>
>>>>> This message is a red herring for the reported issue, the message is also
>>>>> present when the machine boots and the display is brought correctly.
>>>>>
>>>>>> Seems this error is because exynos5800-peach-pit.dts file doesn't have 'ports' node in dp node.
>>>>>>
>>>>>> Below is dp node description of exynos5420-peach-pit.dts file.
>>>>>> &dp {
>>>>>> status = "okay";
>>>>>> pinctrl-names = "default";
>>>>>> pinctrl-0 = <&dp_hpd_gpio>;
>>>>>> samsung,color-space = <0>;
>>>>>> samsung,dynamic-range = <0>;
>>>>>> samsung,ycbcr-coeff = <0>;
>>>>>> samsung,color-depth = <1>;
>>>>>> samsung,link-rate = <0x06>;
>>>>>> samsung,lane-count = <2>;
>>>>>> samsung,hpd-gpio = <&gpx2 6 GPIO_ACTIVE_HIGH>;
>>>>>>
>>>>>> ports {
>>>>>> port at 0 {
>>>>>> dp_out: endpoint {
>>>>>> remote-endpoint = <&bridge_in>;
>>>>>> };
>>>>>> };
>>>>>> };
>>>>>> };
>>>>>>
>>>>>> And below is for exynos5800-peash-pit.dts,
>>>>>> &dp {
>>>>>> status = "okay";
>>>>>> pinctrl-names = "default";
>>>>>> pinctrl-0 = <&dp_hpd_gpio>;
>>>>>> samsung,color-space = <0>;
>>>>>> samsung,dynamic-range = <0>;
>>>>>> samsung,ycbcr-coeff = <0>;
>>>>>> samsung,color-depth = <1>;
>>>>>> samsung,link-rate = <0x0a>;
>>>>>> samsung,lane-count = <2>;
>>>>>> samsung,hpd-gpio = <&gpx2 6 GPIO_ACTIVE_HIGH>;
>>>>>> panel = <&panel>;
>>>>>> };
>>>>>>
>>>>>
>>>>> The difference is because the Exynos5420 Peach Pit Display Port is not
>>>>> attached directly to the display panel, there is an eDP/LVDS bridge chip
>>>>> in the middle (PS8622) while the Exynos5800 Peach Pi doesn't have that.
>>>>>
>>>>> The Exynos DP driver lookups for either a panel phandle or an OF graph
>>>>> endpoint that points to a bridge chip and the bridge enpoint has a port
>>>>> that points to the panel.
>>>>>
>>>>> So the DT is correct but of_graph_get_next_endpoint() always prints an
>>>>
>>>> Then, the DT is really incorrect. As you mentioned, if the Exynos5800 Peach PI
>>>> board doesn't use eDP, then the dp node __should be removed__ from
>>>> exynos5800-peach-pit.dts.
>>>>
>>>> From a common-sense standpoint, there is no any reason to build
>>>> and probe dp driver if the board doesn't use dp hardware.
>>>
>>> I agree with what you say, but unfortunately you've slightly misread
>>> what Javier has said. :) exynos5420-peach-pit has an LVDS panel, with
>>> the eDP -> LVDS bridge in between (ps8622). exynos5800-peach-pi (from
>>> which I am writing this) has an eDP panel directly connected. The DT
>
> Thanks a lot Daniel for clarifying my comments to Inki :)
>
>>> describes both the eDP connector from FIMD and the eDP panel, except
>>> that there is no connection between the DT nodes.
>
> There *is* a connection between the FIMD eDP connector and the eDP panel
> nodes but these are connected using a phandle while the connection for
> the FIMD eDP connector and the eDP/LVDS bridge is using the OF graph DT
> bindings (Documentation/devicetree/bindings/graph.txt).
>
> And also the connection between the eDP/LVDS bridge and the LVDS panel
> is using an OF graph node, so what I meant is that it would be much more
> consistent if both the eDP -> panel and eDP -> eDP/LVDS bridge -> panel
> connections used the OF graph DT bindings.
>
>>
>> Right. I misread what Javier said. :)
>>
>>>
>>>>> error if the port so OF graph endpoints it seems can't be optional as
>>>>> used in this driver. Maybe that message should be change to debug then?
>>>>>
>>>>> Another option is to extend the DP driver DT binding to be more generic
>>>>> supporting having a port to a panel besides a bridge, so we could have
>>>>> something like this for Exynos5800 Peach and be consistent in both cases:
>>>>
>>>> It's really not good. This would make it more complex. The best
>>>> solution is just to
>>>> remove the dt node from the device tree file.
>>>
>>> Given the above, not really. Javier's patch seems correct to me - as
>>> you can see, there is a panel node, and that is the panel that's
>>> really connected.
>>
>> Indeed. Javier's patch will correct it.
>>
>
> Just to be clear, my patch is not correct since the Exynos DP driver and
> its DT binding does not support to connect an FIMD eDP connector to an
> eDP panel directly using OF graph ports / endpoints (only a phandle). But
> is an example of how the DT will look like if we extend to support that.
Yes, you added just a port node for the panel device and removed a panel
property from the device tree file so now dp driver cannot get a device node
object of panel node because now dp driver isn't considered for it yet.
I think there are two ways to correct it. One is,
1. Add a port node for the panel device to the device tree file.
2. Add of_graph dt bindings support for getting the panel node to dp driver
and remove existing of_parse_phandle function call for getting a device
node object for the panel device.
Other is,
1. Revive a panel property and remove the port node you added.
In addition, it seems that existing bridge of_graph dt bindings codes of now
dp driver should be modified like below,
endpoint = of_graph_get_next_endpoint(dev->of_node, panel_endpoint_node);
if (endpoint) {
bridge_node = of_graph_get_remote_port_parent(endpoint);
if (bridge_node) {
dp->bridge = of_drm_find_bridge(bridge_node);
of_node_put(bridge_node);
if (!dp->bridge)
return -EPROBE_DEFER;
} else {
DRM_ERROR("has no port node for the bridge deivce");
return -ENXIO;
}
}
If some board has a bridge device then of_graph_get_remote_port_parent(endpoint)
shouldn't be NULL.
The former looks more reasonable to me.
>
> IIRC at the beginning only eDP -> panel was supported and the phandle
> was used and later when the eDP -> eDP/LVDS bridge -> LVDS panel use
> case was needed, then a bridge phandle was added but Ajay was asked to
> use OF graph instead a phandle and we ended with different approaches
> to connect components depending if a bridge is used or not.
Well, wouldn't it be enough to remove the panel phandle relevant codes
from dp driver and add of_graph dt bindings support for the panel device
to the dp driver instead?
Thanks,
Inki Dae
>
>> Thanks,
>> Inki Dae
>>
>>>
>>>>> --- a/arch/arm/boot/dts/exynos5800-peach-pi.dts
>>>>> +++ b/arch/arm/boot/dts/exynos5800-peach-pi.dts
>>>>> @@ -122,6 +122,12 @@
>>>>> compatible = "auo,b133htn01";
>>>>> power-supply = <&tps65090_fet6>;
>>>>> backlight = <&backlight>;
>>>>> +
>>>>> + port {
>>>>> + panel_in: endpoint {
>>>>> + remote-endpoint = <&dp_out>;
>>>>> + };
>>>>> + };
>>>>> };
>>>>>
>>>>> mmc1_pwrseq: mmc1_pwrseq {
>>>>> @@ -148,7 +154,14 @@
>>>>> samsung,link-rate = <0x0a>;
>>>>> samsung,lane-count = <2>;
>>>>> samsung,hpd-gpio = <&gpx2 6 GPIO_ACTIVE_HIGH>;
>>>>> - panel = <&panel>;
>>>>> +
>>>>> + ports {
>>>>> + port at 0 {
>>>>> + dp_out: endpoint {
>>>>> + remote-endpoint = <&panel_in>;
>>>>> + };
>>>>> + };
>>>>> + };
>>>>> };
>>>
>>> Cheers,
>>> Daniel
>> --
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>>
>
> Best regards,
> --
> Javier Martinez Canillas
> Open Source Group
> Samsung Research America
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